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[2620:137:e000::3:8]) by mx.google.com with ESMTPS id u5-20020a656705000000b005680cb68678si3357758pgf.446.2023.09.22.04.16.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 04:16:09 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=0GcVYMl7; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by fry.vger.email (Postfix) with ESMTP id 0DA1C837D487; Fri, 22 Sep 2023 01:09:38 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232271AbjIVIJE (ORCPT + 30 others); Fri, 22 Sep 2023 04:09:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231888AbjIVIJB (ORCPT ); Fri, 22 Sep 2023 04:09:01 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 769D2CC3 for ; Fri, 22 Sep 2023 01:08:55 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d81ff714678so2554890276.2 for ; Fri, 22 Sep 2023 01:08:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695370134; x=1695974934; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Elogy5+qJLTNkCkBSFtWFfKDNFj74CbHYILaVC5jihg=; b=0GcVYMl7twYtfjutYXgqAJSbiTT/vcDXiio2QOjMt5s0rtQ3gQng4zjEwjSAS1lfPA 0oxdCdF9bYNkdInjHy92YSIcRd0PqUyqqm+CmqjmLrUTB1OT3tQLk13a9Ipgee5iAu1t rIIDC5M3NN9RDkvcf6/chRf3ulgjiO8d/Wfqup3IGcJv1XkJ+YMeKck7yVsSdEqgsbYb HAs4iUsIqWA0wnpsepIiwayR86huK4R13RS0RUo7v80AaDvb4+mWyZvkukzzBytq5PON UlqojhBdbxpXr1aZHasBHeIZZVncw2C1RcUIf3X2skS6WDiyRYS7p1A7M3hpdHNba0IB M7xA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695370134; x=1695974934; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Elogy5+qJLTNkCkBSFtWFfKDNFj74CbHYILaVC5jihg=; b=IweEgGYVqYVJqGgcGK8O9kr+f+vD+3zG/5YKOuBgnfDU/DSB/zpzMYhLf2ylbFLcVs LKRYAEkKQxpUeMdmW6dFRyqVOlJQSBcqhZHeTZjG8LxvCsdpJliLd5+p4P/RVc7vJdn0 umWWEcwXgF0K1nwSCNFj9KW4ja0zmK5Q/Odp/l1W9VeoL/rWT+DIRFzKVd9l8XhBvA5t TWWZarl5dcu5DpwXsx8hftOA0QiloVrd2lmifi+qBjQYTHDDjfkEr3PHXhhX2mMiqals 2p07oALk1WUz6G3jeg3BOQQLsl2th3CrQns0p3PtvdoTdiP4Mk/ZAiKLKOmdyG6cvhEn 2/Rg== X-Gm-Message-State: AOJu0YxBL/K1XIdbT8zaqGt3+Dfr+vqzPW0zt4IsW/1QwVAhoWkaD7CR 65YV8nRS7ESogGW5G5U4gUJp5LkLpKM= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:4da0:80d4:9480:7d5c]) (user=glider job=sendgmr) by 2002:a25:f43:0:b0:d81:754a:7cbb with SMTP id 64-20020a250f43000000b00d81754a7cbbmr101892ybp.11.1695370134613; Fri, 22 Sep 2023 01:08:54 -0700 (PDT) Date: Fri, 22 Sep 2023 10:08:43 +0200 In-Reply-To: <20230922080848.1261487-1-glider@google.com> Mime-Version: 1.0 References: <20230922080848.1261487-1-glider@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230922080848.1261487-2-glider@google.com> Subject: [PATCH v5 1/5] lib/bitmap: add bitmap_{read,write}() From: Alexander Potapenko To: glider@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org, Arnd Bergmann X-Spam-Status: No, score=-8.4 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (fry.vger.email [0.0.0.0]); Fri, 22 Sep 2023 01:09:38 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777736214461254851 X-GMAIL-MSGID: 1777736214461254851 From: Syed Nayyar Waris The two new functions allow reading/writing values of length up to BITS_PER_LONG bits at arbitrary position in the bitmap. The code was taken from "bitops: Introduce the for_each_set_clump macro" by Syed Nayyar Waris with a number of changes and simplifications: - instead of using roundup(), which adds an unnecessary dependency on , we calculate space as BITS_PER_LONG-offset; - indentation is reduced by not using else-clauses (suggested by checkpatch for bitmap_get_value()); - bitmap_get_value()/bitmap_set_value() are renamed to bitmap_read() and bitmap_write(); - some redundant computations are omitted. Cc: Arnd Bergmann Signed-off-by: Syed Nayyar Waris Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/lkml/fe12eedf3666f4af5138de0e70b67a07c7f40338.1592224129.git.syednwaris@gmail.com/ Suggested-by: Yury Norov Co-developed-by: Alexander Potapenko Signed-off-by: Alexander Potapenko --- This patch was previously called "lib/bitmap: add bitmap_{set,get}_value()" (https://lore.kernel.org/lkml/20230720173956.3674987-2-glider@google.com/) v5: - Address comments by Yury Norov: - updated code comments and patch title/description - replace GENMASK(nbits - 1, 0) with BITMAP_LAST_WORD_MASK(nbits) - more compact bitmap_write() implementation v4: - Address comments by Andy Shevchenko and Yury Norov: - prevent passing values >= 64 to GENMASK() - fix commit authorship - change comments - check for unlikely(nbits==0) - drop unnecessary const declarations - fix kernel-doc comments - rename bitmap_{get,set}_value() to bitmap_{read,write}() --- include/linux/bitmap.h | 68 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 03644237e1efb..25998a3a4b2b9 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -76,7 +76,11 @@ struct device; * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst * bitmap_get_value8(map, start) Get 8bit value from map at start + * bitmap_read(map, start, nbits) Read an nbits-sized value from + * map at start * bitmap_set_value8(map, value, start) Set 8bit value to map at start + * bitmap_write(map, value, start, nbits) Write an nbits-sized value to + * map at start * * Note, bitmap_zero() and bitmap_fill() operate over the region of * unsigned longs, that is, bits behind bitmap till the unsigned long @@ -583,6 +587,33 @@ static inline unsigned long bitmap_get_value8(const unsigned long *map, return (map[index] >> offset) & 0xFF; } +/** + * bitmap_read - read a value of n-bits from the memory region + * @map: address to the bitmap memory region + * @start: bit offset of the n-bit value + * @nbits: size of value in bits, up to BITS_PER_LONG + * + * Returns: value of nbits located at the @start bit offset within the @map + * memory region. + */ +static inline unsigned long bitmap_read(const unsigned long *map, + unsigned long start, + unsigned long nbits) +{ + size_t index = BIT_WORD(start); + unsigned long offset = start % BITS_PER_LONG; + unsigned long space = BITS_PER_LONG - offset; + unsigned long value_low, value_high; + + if (unlikely(!nbits)) + return 0; + if (space >= nbits) + return (map[index] >> offset) & GENMASK(nbits - 1, 0); + value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); + value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); + return (value_low >> offset) | (value_high << space); +} + /** * bitmap_set_value8 - set an 8-bit value within a memory region * @map: address to the bitmap memory region @@ -599,6 +630,43 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value, map[index] |= value << offset; } +/** + * bitmap_write - write n-bit value within a memory region + * @map: address to the bitmap memory region + * @value: value to write, clamped to nbits + * @start: bit offset of the n-bit value + * @nbits: size of value in bits, up to BITS_PER_LONG. + * + * bitmap_write() behaves similarly to @nbits calls of assign_bit(), i.e. bits + * beyond @nbits are ignored: + * + * for (bit = 0; bit < nbits; bit++) + * assign_bit(start + bit, bitmap, val & BIT(bit)); + */ +static inline void bitmap_write(unsigned long *map, + unsigned long value, + unsigned long start, unsigned long nbits) +{ + size_t index = BIT_WORD(start); + unsigned long offset = start % BITS_PER_LONG; + unsigned long space = BITS_PER_LONG - offset; + unsigned long mask; + + if (unlikely(!nbits)) + return; + mask = BITMAP_LAST_WORD_MASK(nbits); + value &= mask; + if (space >= nbits) { + map[index] &= ~(mask << offset); + map[index] |= value << offset; + return; + } + map[index] &= ~BITMAP_FIRST_WORD_MASK(start); + map[index] |= value << offset; + map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits); + map[index + 1] |= (value >> space); +} + #endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ From patchwork Fri Sep 22 08:08:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 143317 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5448012vqi; 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[23.128.96.31]) by mx.google.com with ESMTPS id bg26-20020a056a02011a00b00563e283786esi1157389pgb.104.2023.09.22.03.05.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 03:05:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) client-ip=23.128.96.31; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=FipK+GnX; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.31 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by morse.vger.email (Postfix) with ESMTP id DBBD38099253; Fri, 22 Sep 2023 01:10:23 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232348AbjIVIJM (ORCPT + 30 others); Fri, 22 Sep 2023 04:09:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232224AbjIVIJJ (ORCPT ); Fri, 22 Sep 2023 04:09:09 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40E73CC4 for ; Fri, 22 Sep 2023 01:08:58 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-59bf252a83aso24311297b3.3 for ; Fri, 22 Sep 2023 01:08:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695370137; x=1695974937; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=E6HfQ9ajoFejClPit+nbh4c2FH86MesGxxER+WNLYXg=; b=FipK+GnXe2J2eyclLSVD9C9jz5T9FkViVdQxkil007GSvHmnlMfjRTsFEdHNxbxZQg iKWL/GzJJ8fJnf0m7cqdhiczrqtq8Pu28b1lerc2SHbAyM0Pc8hX6sCyR7apRrHw5I5z m9F6/Rc5XCpfPX/0z0uEw63waz0MRF8f3aIC3zBuaFrp/MkicX4RDso7mss8qW4fcXlE 8rB55W+GIS8oCos2gvC0A4qPiP0yLhFSG2lPQJQfBND+mwstVx1Q86QsLnhTYnz+BTNR rzMpPKIBR0OresxeSJRK8WiFp7pWwaoHfsvDJkth07rQaI0ahCsAdkCRucxUPeKF35jA Y25g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695370137; x=1695974937; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=E6HfQ9ajoFejClPit+nbh4c2FH86MesGxxER+WNLYXg=; b=emH/ajXq2fHe06AIgcWMK7iGlVbdc/iOXvfWStnWokRv99Oj3JM/D4iymStTntwIOI u6NZhX1LsoSe6jro0pEuPu+I7nANphVnSCGQCObzMqz+G2qo4GrKQIWksUXOHDkwuVqk 2jv1aDVHRmbpRi6P4/kshxVwaxvXcBmaSssM8CBXBQIp/iHJQtiUAgJh55zx8QKPipss MA1BuS7BCKaFLYnCdF31C+jAjORlrAo2LZ4VHF0bWSID3GMNfgqo6FrupmKTTrmseVMY e9bdRmq54b8fKZgIB6rJfo5fah2BquiH2uulE+RrT/q3RovKv8S1MX3DkRYI6MP+YBL5 HsmQ== X-Gm-Message-State: AOJu0Yw8lXadTQc16C044IMKAlqC4+bDMVNz8d8/FN9HhBEVTLw/MPkM F6Ac9ut61iO079U1f57b0A8LKB/q6qM= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:4da0:80d4:9480:7d5c]) (user=glider job=sendgmr) by 2002:a81:af1c:0:b0:59b:db15:498c with SMTP id n28-20020a81af1c000000b0059bdb15498cmr119630ywh.10.1695370137358; Fri, 22 Sep 2023 01:08:57 -0700 (PDT) Date: Fri, 22 Sep 2023 10:08:44 +0200 In-Reply-To: <20230922080848.1261487-1-glider@google.com> Mime-Version: 1.0 References: <20230922080848.1261487-1-glider@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230922080848.1261487-3-glider@google.com> Subject: [PATCH v5 2/5] lib/test_bitmap: add tests for bitmap_{read,write}() From: Alexander Potapenko To: glider@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org X-Spam-Status: No, score=-8.4 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Fri, 22 Sep 2023 01:10:23 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777731745438576972 X-GMAIL-MSGID: 1777731745438576972 Add basic tests ensuring that values can be added at arbitrary positions of the bitmap, including those spanning into the adjacent unsigned longs. Signed-off-by: Alexander Potapenko Reviewed-by: Andy Shevchenko --- This patch was previously called "lib/test_bitmap: add tests for bitmap_{set,get}_value()" (https://lore.kernel.org/lkml/20230720173956.3674987-3-glider@google.com/) and "lib/test_bitmap: add tests for bitmap_{set,get}_value_unaligned" (https://lore.kernel.org/lkml/20230713125706.2884502-3-glider@google.com/) v5: - update patch title - address Yury Norov's comments: - rename the test cases - factor out test_bitmap_write_helper() to test writing over different background patterns; - add a test case copying a nontrivial value bit-by-bit; - drop volatile v4: - Address comments by Andy Shevchenko: added Reviewed-by: and a link to the previous discussion - Address comments by Yury Norov: - expand the bitmap to catch more corner cases - add code testing that bitmap_set_value() does not touch adjacent bits - add code testing the nbits==0 case - rename bitmap_{get,set}_value() to bitmap_{read,write}() v3: - switch to using bitmap_{set,get}_value() - change the expected bit pattern in test_set_get_value(), as the test was incorrectly assuming 0 is the LSB. --- lib/test_bitmap.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 187f5b2db4cf1..ea66e39b29a4e 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -71,6 +71,17 @@ __check_eq_uint(const char *srcfile, unsigned int line, return true; } +static bool __init +__check_eq_ulong(const char *srcfile, unsigned int line, + const unsigned long exp_ulong, unsigned long x) +{ + if (exp_ulong != x) { + pr_err("[%s:%u] expected %lu, got %lu\n", + srcfile, line, exp_ulong, x); + return false; + } + return true; +} static bool __init __check_eq_bitmap(const char *srcfile, unsigned int line, @@ -186,6 +197,7 @@ __check_eq_str(const char *srcfile, unsigned int line, }) #define expect_eq_uint(...) __expect_eq(uint, ##__VA_ARGS__) +#define expect_eq_ulong(...) __expect_eq(ulong, ##__VA_ARGS__) #define expect_eq_bitmap(...) __expect_eq(bitmap, ##__VA_ARGS__) #define expect_eq_pbl(...) __expect_eq(pbl, ##__VA_ARGS__) #define expect_eq_u32_array(...) __expect_eq(u32_array, ##__VA_ARGS__) @@ -1222,6 +1234,108 @@ static void __init test_bitmap_const_eval(void) BUILD_BUG_ON(~var != ~BIT(25)); } +/* + * Test bitmap should be big enough to include the cases when start is not in + * the first word, and start+nbits lands in the following word. + */ +#define TEST_BIT_LEN (1000) +#define TEST_BYTE_LEN (BITS_TO_BYTES(TEST_BIT_LEN)) + +/* + * Helper function to test bitmap_write() overwriting the chosen byte pattern. + */ +static void __init test_bitmap_write_helper(unsigned char pattern) +{ + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + DECLARE_BITMAP(exp_bitmap, TEST_BIT_LEN); + unsigned long w, r, bit; + int i, n, nbits; + + /* + * Check that setting a single bit does not accidentally touch the + * adjacent bits. + */ + for (i = 0; i < TEST_BIT_LEN; i++) { + /* + * A 0b10101010 pattern to catch both 0s replaced to 1s + * and vice versa. + */ + memset(bitmap, pattern, TEST_BYTE_LEN); + memset(exp_bitmap, pattern, TEST_BYTE_LEN); + for (bit = 0; bit <= 1; bit++) { + bitmap_write(bitmap, bit, i, 1); + __assign_bit(i, exp_bitmap, bit); + expect_eq_bitmap(exp_bitmap, bitmap, + TEST_BIT_LEN); + } + } + + /* Ensure setting 0 bits does not change anything. */ + memset(bitmap, pattern, TEST_BYTE_LEN); + memset(exp_bitmap, pattern, TEST_BYTE_LEN); + for (i = 0; i < TEST_BIT_LEN; i++) { + bitmap_write(bitmap, ~0UL, i, 0); + expect_eq_bitmap(exp_bitmap, bitmap, TEST_BIT_LEN); + } + + for (nbits = BITS_PER_LONG; nbits >= 1; nbits--) { + w = 0xdeadbeefdeadbeefUL >> (BITS_PER_LONG - nbits); + for (i = 0; i <= TEST_BIT_LEN - nbits; i++) { + memset(bitmap, pattern, TEST_BYTE_LEN); + memset(exp_bitmap, pattern, TEST_BYTE_LEN); + for (n = 0; n < nbits; n++) + __assign_bit(i + n, exp_bitmap, w & BIT(n)); + bitmap_write(bitmap, w, i, nbits); + expect_eq_bitmap(exp_bitmap, bitmap, TEST_BIT_LEN); + r = bitmap_read(bitmap, i, nbits); + expect_eq_ulong(r, w); + } + } +} + +static void __init test_bitmap_read_write(void) +{ + unsigned char pattern[3] = {0x00, 0xaa, 0xff}; + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + unsigned long zero_bits = 0; + unsigned long val; + int i, pi; + + /* + * Setting/getting zero bytes should not crash the kernel. + * READ_ONCE() prevents constant folding. + */ + bitmap_write(NULL, 0, 0, READ_ONCE(zero_bits)); + val = bitmap_read(NULL, 0, READ_ONCE(zero_bits)); + expect_eq_ulong(0, val); + + /* + * Ensure that bitmap_read() reads the same value that was previously + * written, and two consequent values are correctly merged. + * The resulting bit pattern is asymmetric to rule out possible issues + * with bit numeration order. + */ + for (i = 0; i < TEST_BIT_LEN - 7; i++) { + bitmap_zero(bitmap, TEST_BIT_LEN); + + bitmap_write(bitmap, 0b10101UL, i, 5); + val = bitmap_read(bitmap, i, 5); + expect_eq_ulong(0b10101UL, val); + + bitmap_write(bitmap, 0b101UL, i + 5, 3); + val = bitmap_read(bitmap, i + 5, 3); + expect_eq_ulong(0b101UL, val); + + val = bitmap_read(bitmap, i, 8); + expect_eq_ulong(0b10110101UL, val); + } + + for (pi = 0; pi < sizeof(pattern); pi++) + test_bitmap_write_helper(pattern[pi]); +} +#undef TEST_BYTE_LEN +#undef TEST_BIT_LEN + static void __init selftest(void) { test_zero_clear(); @@ -1237,6 +1351,7 @@ static void __init selftest(void) test_bitmap_cut(); test_bitmap_print_buf(); test_bitmap_const_eval(); + test_bitmap_read_write(); test_find_nth_bit(); test_for_each_set_bit(); From patchwork Fri Sep 22 08:08:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 143253 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5405213vqi; 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[23.128.96.34]) by mx.google.com with ESMTPS id f12-20020a170902ce8c00b001a6ef92d441si3695410plg.599.2023.09.22.01.24.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 01:24:43 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) client-ip=23.128.96.34; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=VFXxQj7T; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id 16E0D850FAC4; Fri, 22 Sep 2023 01:09:18 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232336AbjIVIJQ (ORCPT + 30 others); Fri, 22 Sep 2023 04:09:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232285AbjIVIJL (ORCPT ); Fri, 22 Sep 2023 04:09:11 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 139ABCF3 for ; Fri, 22 Sep 2023 01:09:00 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d858d1bdf0aso2400193276.1 for ; Fri, 22 Sep 2023 01:09:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695370140; x=1695974940; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=nl/fxf+qx8ISJuSoVh6mGCYH3LWVJFzsWE1L3WeUseU=; b=VFXxQj7TYSpLCGaJCd/rBcLfz+CO9xXJ99X04ZYJStW0BKENd+7E+RwYLu24EA2fSt XYm5Tki75xQjPfKdhnSnmNEBe5xAf7pE6Rt5Fg/OUrXNWewByvStEYc2sOI9evJxC6yq Ix77NhvzlhDPAPn/RUloRQwkkbvibTBLwfJDy335JBHRSRtzqW3C+bl6xrqzfTWjkpVv ORM2CLboisRhCF9CkBYHcqmjzxEsI588xzmt1JVebb7tYhRjWCuOqMN7mmMnO5R7AGel bgf2uV6Wo/L14H85959rgjPweyfDl4c2z+K/lB4suR0D8Z8zX9hc0EmmhEifbhQAProD DxYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695370140; x=1695974940; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nl/fxf+qx8ISJuSoVh6mGCYH3LWVJFzsWE1L3WeUseU=; b=FfrHezuwI8RHrHVysJ8m/IT44rcQgu3x4k5GGHNqSQ2KxoipKi4RZrhXhmBI2kJcW4 FioUWHnFvrLryvEVuDbnw1V4zitf5nFNBXiQ9Jqm63VPTHRw/Yagm8E5KMQ2idpILqDN lrZZ68QHrOlG/ME42NLCe3HadP4yz8LOV+cz0fRM2tlhtwMflXO4c4nAsQYR7TWAqjVH n5PCSWjXjZ6MWMo/ePZ0dZrmSsUaVfMMxu0zf9iUbffjTjcNt8H5R/tU/poc/4WiLtPx w8jE1IQfsuQZHE6Rx2i6KTTM5KHc20tYfkiPHUuPC3TBasFR/y6KUDshQ46ZRlKW97SQ oNow== X-Gm-Message-State: AOJu0Yz7fGmtV0r60mk5PAqZ6fLAgMEMJT68QotzHYf3hiwAwlzXSnUr +bJQJbRBlAQm8TeFm+DdIb3OoEMBWnA= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:4da0:80d4:9480:7d5c]) (user=glider job=sendgmr) by 2002:a25:e6d2:0:b0:d7f:2cb6:7d8c with SMTP id d201-20020a25e6d2000000b00d7f2cb67d8cmr103333ybh.13.1695370140239; Fri, 22 Sep 2023 01:09:00 -0700 (PDT) Date: Fri, 22 Sep 2023 10:08:45 +0200 In-Reply-To: <20230922080848.1261487-1-glider@google.com> Mime-Version: 1.0 References: <20230922080848.1261487-1-glider@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230922080848.1261487-4-glider@google.com> Subject: [PATCH v5 3/5] arm64: mte: implement CONFIG_ARM64_MTE_COMP From: Alexander Potapenko To: glider@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Fri, 22 Sep 2023 01:09:18 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777725429408726294 X-GMAIL-MSGID: 1777725429408726294 The config implements the algorithm compressing memory tags for ARM MTE during swapping. The algorithm is based on RLE and specifically targets buffers of tags corresponding to a single page. In the common case a buffer can be compressed into 63 bits, making it possible to store it without additional memory allocation. Suggested-by: Evgenii Stepanov Signed-off-by: Alexander Potapenko --- v5: - make code PAGE_SIZE-agnostic, remove hardcoded constants, updated the docs - implement debugfs interface - Address comments by Andy Shevchenko: - update description of mtecomp.c - remove redundant assignments, simplify mte_tags_to_ranges() - various code simplifications - introduce mtecomp.h - add :export: to Documentation/arch/arm64/mte-tag-compression.rst v4: - Addressed comments by Andy Shevchenko: - expanded "MTE" to "Memory Tagging Extension" in Kconfig - fixed kernel-doc comments, moved them to C source - changed variables to unsigned where applicable - some code simplifications, fewer unnecessary assignments - added the mte_largest_idx_bits() helper - added namespace prefixes to all functions - added missing headers (but removed bits.h) - Addressed comments by Yury Norov: - removed test-only functions from mtecomp.h - dropped the algoritm name (all functions are now prefixed with "mte") - added more comments - got rid of MTE_RANGES_INLINE - renamed bitmap_{get,set}_value() to bitmap_{read,write}() - moved the big comment explaining the algorithm to Documentation/arch/arm64/mte-tag-compression.rst, expanded it, add a link to it from Documentation/arch/arm64/index.rst - removed hardcoded ranges from mte_alloc_size()/mte_size_to_ranges() v3: - Addressed comments by Andy Shevchenko: - use bitmap_{set,get}_value() writte by Syed Nayyar Waris - switched to unsigned long everywhere (fewer casts) - simplified the code, removed redundant checks - dropped ea0_compress_inline() - added bit size constants and helpers to access the bitmap - explicitly initialize all compressed sizes in ea0_compress_to_buf() - initialize all handle bits v2: - as suggested by Yury Norov, switched from struct bitq (which is not needed anymore) to - add missing symbol exports --- Documentation/arch/arm64/index.rst | 1 + .../arch/arm64/mte-tag-compression.rst | 245 +++++++++ arch/arm64/Kconfig | 11 + arch/arm64/include/asm/mtecomp.h | 13 + arch/arm64/mm/Makefile | 1 + arch/arm64/mm/mtecomp.c | 467 ++++++++++++++++++ arch/arm64/mm/mtecomp.h | 12 + 7 files changed, 750 insertions(+) create mode 100644 Documentation/arch/arm64/mte-tag-compression.rst create mode 100644 arch/arm64/include/asm/mtecomp.h create mode 100644 arch/arm64/mm/mtecomp.c create mode 100644 arch/arm64/mm/mtecomp.h diff --git a/Documentation/arch/arm64/index.rst b/Documentation/arch/arm64/index.rst index d08e924204bf1..bf6c1583233a9 100644 --- a/Documentation/arch/arm64/index.rst +++ b/Documentation/arch/arm64/index.rst @@ -19,6 +19,7 @@ ARM64 Architecture legacy_instructions memory memory-tagging-extension + mte-tag-compression perf pointer-authentication ptdump diff --git a/Documentation/arch/arm64/mte-tag-compression.rst b/Documentation/arch/arm64/mte-tag-compression.rst new file mode 100644 index 0000000000000..c5170155473aa --- /dev/null +++ b/Documentation/arch/arm64/mte-tag-compression.rst @@ -0,0 +1,245 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================================== +Tag Compression for Memory Tagging Extension (MTE) +================================================== + +This document describes the algorithm used to compress memory tags used by the +ARM Memory Tagging Extension (MTE) + +Introduction +============ + +MTE assigns tags to memory pages: for 4K pages those tags occupy 128 bytes +(256 4-bit tags each corresponding to a 16-byte MTE granule), for 16K pages - +512 bytes, for 64K pages - 2048 bytes. By default, MTE carves out 3.125% (1/16) +of the available physical memory to store the tags. + +When MTE pages are saved to swap, their tags need to be stored in the kernel +memory. If the system swap is used heavily, these tags may take a substantial +portion of the physical memory. To reduce memory waste, +``CONFIG_ARM64_MTE_COMP`` allows the kernel to store the tags in compressed +form. + +Implementation details +====================== + +The algorithm attempts to compress an array of ``MTE_PAGE_TAG_STORAGE`` +tag bytes into a byte sequence that can be stored in one of the smaller size +class allocations (for 4K pages those are 16-, 32-, or 64-byte allocations). +A special case is storing the tags inline in an 8-byte pointer. + +Tag manipulation and storage +---------------------------- + +Tags for swapped pages are stored in an XArray that maps swap entries to 63-bit +values (see ``arch/arm64/mm/mteswap.c``). In the case when +``CONFIG_ARM64_MTE_COMP=n``, these values contain pointers to uncompressed +buffers allocated with kmalloc(). Otherwise, they are 63-bit handles used by the +functions declared in ``arch/arm64/include/asm/mtecomp.h``: + +- mte_compress() compresses the given ``MTE_PAGE_TAG_STORAGE``-byte ``tags`` + buffer, allocates storage for it, and returns an opaque handle addressing + that storage; +- mte_decompress() decompresses the tags addressed by ``handle`` + and fills the ``MTE_PAGE_TAG_STORAGE``-byte ``tags`` buffer; +- mte_release_handle() releases the storage handle returned by + mte_compress() (so that this handle cannot be used anymore); +- mte_storage_size() calculates the size occupied by the tags addressed + by ``handle``. + +Depending on the size of compressed data, ``mte_compress()`` stores it in one of +the size classes backed by kmem caches: ``mte-tags-{16,32,64,128}`` for the +4K-page case (``mte-tags-128`` being used for the data that cannot be compressed +into 64 bytes and is stored uncompressed). +A practical common case allows the tags to be compressed into 8 bytes - then +they are stored in the handle itself. + +Handle format +------------- + +The handle returned by ``mte_compress()`` is an ``unsigned long`` that has its +bit 63 set to 0 (XArray entries must not exceed ``LONG_MAX``):: + + 63 62 60 ... 2 0 + +---+--------+-----+------------+ + | 0 | INLINE | ... | SIZE_LOG | + +---+--------+-----+------------+ + +Bits ``62..60`` is the inline/out-of-line marker: if they all are set to 1, the +data is stored out-of-line in the buffer pointed to by +``(handle | BIT(63)) & ~7UL``. Otherwise, the data is stored inline in the +handle itself. + +Bits ``2..0`` denote the size for out-of-line allocations:: + + size = 16 << (handle & 0b111) + + +Tag compression +--------------- + +The compression algorithm is a variation of RLE (run-length encoding) and works +as follows (we'll be considering 4K pages and 128-byte tag buffers, but the same +approach scales to 16- and 64K pages): + +1. The input array of 128 (``MTE_PAGE_TAG_STORAGE``) bytes is transformed into + tag ranges (two arrays: ``r_tags[]`` containing tag values and ``r_sizes[]`` + containing range lengths) by ``mte_tags_to_ranges()``. Note that + ``r_sizes[]`` sums up to 256 (``MTE_GRANULES_PER_PAGE``). + +2. The number of the largest element of ``r_sizes[]`` is stored in + ``largest_idx``. The element itself is thrown away from ``r_sizes[]``, + because it can be reconstructed from the sum of the remaining elements. Note + that now none of the remaining ``r_sizes[]`` elements exceeds + ``MTE_PAGE_TAG_STORAGE - 1``. + +3. Depending on the number ``N`` of ranges, a storage class is picked:: + + N <= 6: 8 bytes (inline case, no allocation required); + 6 < N <= 11: 16 bytes + 11 < N <= 23: 32 bytes + 23 < N <= 46: 64 bytes + 46 < N: 128 bytes (no compression will be performed) + +(See `Why these numbers?`_ below). + +4. For the inline case, the following values are stored packed in the 8-byte + handle (``i`` means a ````-bit unsigned integer):: + + largest_idx : i4 + r_tags[0..5] : i4 x 6 + r_sizes[0..4] : i7 x 5 + + (if N is less than 6, ``r_tags`` and ``r_sizes`` are padded up with zero + values) + + Because ``largest_idx`` is <= 5, bit 63 of the handle is always 0 (so the + handle can be stored in an Xarray), and bits 62..60 cannot all be 1 (so the + handle can be distinguished from a kernel pointer). + +5. For the out-of-line case, the storage is allocated from one of the + ``mte-tags-{16,32,64,128}`` kmem caches. The resulting pointer is aligned + on 8 bytes, so its bits 2..0 can be used to store the size class (see above). + + Bit 63 of the pointer is zeroed out, so that it can be stored in XArray. + +6. The data layout in the allocated storage is as follows:: + + largest_idx : i6 + r_tags[0..N] : i4 x N + r_sizes[0..N-1] : i7 x (N-1) + +Tag decompression +----------------- + +The decompression algorithm performs the steps below. + +1. Decide if data is stored inline (bits ``62..60`` of the handle ``!= 0b111``) + or out-of line. + +2. For the inline case, treat the handle itself as the input buffer. + +3. For the out-of-line case, look at bits ``2..0`` of the handle to understand + the input buffer length. To obtain the pointer to the input buffer, unset + bits ``2..0`` of the handle and set bit ``63``. + +4. If the input buffer is 128 byte long, copy its contents to the output + buffer. + +5. Otherwise, read ``largest_idx``, ``r_tags[]`` and ``r_sizes[]`` from the + input buffer. Calculate the removed largest element of ``r_sizes[]`` as + ``largest = 256 - sum(r_sizes)`` and insert it into ``r_sizes`` at + position ``largest_idx``. + +6. For each ``r_sizes[i] > 0``, add a 4-bit value ``r_tags[i]`` to the output + buffer ``r_sizes[i]`` times. + + +Why these numbers? +------------------ + +To be able to reconstruct N tag ranges from the compressed data, we need to +store ``largest_idx``, ``r_tags[N]``, and ``r_sizes[N-1]``. Knowing that the +sizes do not exceed ``MTE_PAGE_TAG_STORAGE``, those can be packed into +``S = ilog2(MTE_PAGE_TAG_STORAGE)`` bits, whereas a single tag occupies +4 bits, and ``largest_idx`` cannot take more than +``Lmax = ilog2(MTE_GRANULES_PER_PAGE)`` bits. + +Now, for each ``B``-byte size class it is possible to find the maximal number +``M`` such as ``Lmax + 4 * M + S * (M - 1) <= 8 * B``, +i.e. ``M = (8 * B - 1) / 11``:: + + 4K pages: S = 7 + +-------------+----+--------------+ + | Buffer size | M | Storage bits | + +-------------+----+--------------+ + | 8 | 5 | 56 | + | 16 | 11 | 122 | + | 32 | 23 | 254 | + | 64 | 46 | 507 | + +-------------+----+--------------+ + +We can notice that ``M`` (and therefore ``largest_idx``) actually always fits +into 6 bits. For the inline case it is even guaranteed to fit into 3 bits, which +lets us squeeze an extra range into a 8-byte buffer. Because the inline case +requires bit 63 of the handle to be zero, we add that bit to ``largest_idx``, +knowing it will not be used. + +For the revised ``largest_idx`` sizes, we now pick the maximal number ``N`` +such as ``(L + 4 * N + 7 * (N - 1) <= 8 * S``, where ``L = 4`` in the inline +case and ``L = 6`` otherwise. +In other words, ``N = (8 * S + 7 - L) / 11``, therefore:: + + 4K pages: S = 7, L_i = 4, L_o = 6 + +-------------+----+--------------+ + | Buffer size | N | Storage bits | + +-------------+----+--------------+ + | 8 | 6 | 63 | + | 16 | 11 | 120 | + | 32 | 23 | 252 | + | 64 | 46 | 505 | + +-------------+----+--------------+ + +Similarly, for other page sizes:: + + 16K pages: S = 9, L_i = 4, L_o = 8 + +-------------+-----+--------------+ + | Buffer size | N | Storage bits | + +-------------+-----+--------------+ + | 8 | 5 | 60 | + | 16 | 9 | 116 | + | 32 | 19 | 246 | + | 64 | 39 | 506 | + | 128 | 78 | 1013 | + | 256 | 157 | 2040 | + +-------------+-----+--------------+ + + 64K pages: S = 11, L_i = 4, L_o = 10 + +-------------+-----+--------------+ + | Buffer size | N | Storage bits | + +-------------+-----+--------------+ + | 8 | 4 | 53 | + | 16 | 8 | 119 | + | 32 | 17 | 254 | + | 64 | 34 | 509 | + | 128 | 68 | 1019 | + | 256 | 136 | 2039 | + | 512 | 273 | 4094 | + | 1024 | 546 | 8189 | + +-------------+-----+--------------+ + + +Note +---- + +Tag compression and decompression implicitly rely on the fixed MTE tag size +(4 bits) and number of tags per page. Should these values change, the algorithm +may need to be revised. + + +Programming Interface +===================== + + .. kernel-doc:: arch/arm64/mm/mtecomp.c + :export: diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a2511b30d0f67..d4fb3b8d11d77 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2093,6 +2093,17 @@ config ARM64_EPAN if the cpu does not implement the feature. endmenu # "ARMv8.7 architectural features" +config ARM64_MTE_COMP + bool "Tag compression for ARM64 Memory Tagging Extension" + default y + depends on ARM64_MTE + help + Enable tag compression support for ARM64 Memory Tagging Extension. + + Tag buffers corresponding to swapped RAM pages are compressed using + RLE to conserve heap memory. In the common case compressed tags + occupy 2.5x less memory. + config ARM64_SVE bool "ARM Scalable Vector Extension support" default y diff --git a/arch/arm64/include/asm/mtecomp.h b/arch/arm64/include/asm/mtecomp.h new file mode 100644 index 0000000000000..71552bc429882 --- /dev/null +++ b/arch/arm64/include/asm/mtecomp.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __ASM_MTECOMP_H +#define __ASM_MTECOMP_H + +#include + +unsigned long mte_compress(u8 *tags); +bool mte_decompress(unsigned long handle, u8 *tags); +void mte_release_handle(unsigned long handle); +size_t mte_storage_size(unsigned long handle); + +#endif // __ASM_MTECOMP_H diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index dbd1bc95967d0..46778f6dd83c2 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -10,6 +10,7 @@ obj-$(CONFIG_TRANS_TABLE) += trans_pgd.o obj-$(CONFIG_TRANS_TABLE) += trans_pgd-asm.o obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o obj-$(CONFIG_ARM64_MTE) += mteswap.o +obj-$(CONFIG_ARM64_MTE_COMP) += mtecomp.o KASAN_SANITIZE_physaddr.o += n obj-$(CONFIG_KASAN) += kasan_init.o diff --git a/arch/arm64/mm/mtecomp.c b/arch/arm64/mm/mtecomp.c new file mode 100644 index 0000000000000..e2c8f9ef30ca0 --- /dev/null +++ b/arch/arm64/mm/mtecomp.c @@ -0,0 +1,467 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * MTE tag compression algorithm. + * See Documentation/arch/arm64/mte-tag-compression.rst for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "mtecomp.h" + +/* The handle must fit into an Xarray value. */ +#define MTE_HANDLE_MASK GENMASK_ULL(62, 0) + +/* Out-of-line handles have 0b111 in bits 62..60. */ +#define MTE_NOINLINE_MASK GENMASK_ULL(62, 60) + +/* Cache index is stored in the lowest pointer bits. */ +#define MTE_CACHE_ID_MASK GENMASK_ULL(2, 0) + +/* Caches start at mte-tags-16 and go up to mte-tags-MTE_PAGE_TAG_STORAGE. */ +#define MTECOMP_NUM_CACHES ilog2(MTE_PAGE_TAG_STORAGE / 8) +static struct kmem_cache *mtecomp_caches[MTECOMP_NUM_CACHES]; +/* + * [0] - store the numbers of created/released inline handles; + * [1..MTECOMP_NUM_CACHES] - store the number of allocations/deallocations from + * mtecomp_caches. + */ +static atomic_long_t alloc_counters[MTECOMP_NUM_CACHES + 1]; +static atomic_long_t dealloc_counters[MTECOMP_NUM_CACHES + 1]; + +/* + * Largest number of ranges, for which compressed data fits into 63 bits, can + * be encoded with 4 bits. + */ +#define MTE_BITS_PER_LARGEST_IDX_INLINE 4 +/* + * In the worst case every tag is different, then largest index can be up to + * MTE_GRANULES_PER_PAGE. + */ +#define MTE_BITS_PER_LARGEST_IDX ilog2(MTE_GRANULES_PER_PAGE) +/* Range size cannot exceed MTE_GRANULES_PER_PAGE / 2. */ +#define MTE_BITS_PER_SIZE (MTE_BITS_PER_LARGEST_IDX - 1) + +/* Translate allocation size into mtecomp_caches[] index. */ +static unsigned int mte_size_to_cache_id(size_t len) +{ + return fls(len) - 5; +} + +/* Translate mtecomp_caches[] index into allocation size. */ +static size_t mte_cache_id_to_size(unsigned int id) +{ + return 16 << id; +} + +/** + * mte_tags_to_ranges() - break @tags into arrays of tag ranges. + * @tags: MTE_GRANULES_PER_PAGE-byte array containing MTE tags. + * @out_tags: u8 array to store the tag of every range. + * @out_sizes: unsigned short array to store the size of every range. + * @out_len: length of @out_tags and @out_sizes (output parameter, initially + * equal to lengths of out_tags[] and out_sizes[]). + */ +void mte_tags_to_ranges(u8 *tags, u8 *out_tags, unsigned short *out_sizes, + size_t *out_len) +{ + u8 prev_tag = tags[0] / 16; /* First tag in the array. */ + unsigned int cur_idx = 0, i, j; + u8 cur_tag; + + memset(out_tags, 0, array_size(*out_len, sizeof(*out_tags))); + memset(out_sizes, 0, array_size(*out_len, sizeof(*out_sizes))); + + out_tags[cur_idx] = prev_tag; + for (i = 0; i < MTE_GRANULES_PER_PAGE; i++) { + j = i % 2; + cur_tag = j ? (tags[i / 2] % 16) : (tags[i / 2] / 16); + if (cur_tag == prev_tag) { + out_sizes[cur_idx]++; + } else { + cur_idx++; + prev_tag = cur_tag; + out_tags[cur_idx] = prev_tag; + out_sizes[cur_idx] = 1; + } + } + *out_len = cur_idx + 1; +} +EXPORT_SYMBOL_NS(mte_tags_to_ranges, MTECOMP); + +/** + * mte_ranges_to_tags() - fill @tags using given tag ranges. + * @r_tags: u8[] containing the tag of every range. + * @r_sizes: unsigned short[] containing the size of every range. + * @r_len: length of @r_tags and @r_sizes. + * @tags: MTE_GRANULES_PER_PAGE-byte array to write the tags to. + */ +void mte_ranges_to_tags(u8 *r_tags, unsigned short *r_sizes, size_t r_len, + u8 *tags) +{ + unsigned int i, j, pos = 0; + u8 prev; + + for (i = 0; i < r_len; i++) { + for (j = 0; j < r_sizes[i]; j++) { + if (pos % 2) + tags[pos / 2] = (prev << 4) | r_tags[i]; + else + prev = r_tags[i]; + pos++; + } + } +} +EXPORT_SYMBOL_NS(mte_ranges_to_tags, MTECOMP); + +/* + * Translate allocation size into maximum number of ranges that it can hold. + * + * It is the biggest number N such as: + * MTE_BITS_PER_LARGEST_IDX_INLINE + MTE_TAG_SIZE * N + * + MTE_BITS_PER_SIZE * (N-1) <= 63 bits, + * for the inline case, or + * MTE_BITS_PER_LARGEST_IDX + * + MTE_TAG_SIZE * N + MTE_BITS_PER_SIZE * (N-1) <= tag array size in bits, + * for the out-of line case. + */ +static size_t mte_size_to_ranges(size_t size) +{ + size_t largest_bits; + + largest_bits = (size == 8) ? MTE_BITS_PER_LARGEST_IDX_INLINE : + MTE_BITS_PER_LARGEST_IDX; + return (size * 8 + MTE_BITS_PER_SIZE - largest_bits) / + (MTE_TAG_SIZE + MTE_BITS_PER_SIZE); +} + +/* Translate @num_ranges into the allocation size needed to hold them. */ +static size_t mte_alloc_size(unsigned int num_ranges) +{ + size_t size = 8; + + while (size < (1 << MTE_BITS_PER_SIZE)) { + if (num_ranges <= mte_size_to_ranges(size)) + return size; + size <<= 1; + } + return size; +} + +/* Is the data stored inline in the handle itself? */ +static bool mte_is_inline(unsigned long handle) +{ + return (handle & MTE_NOINLINE_MASK) != MTE_NOINLINE_MASK; +} + +/** + * mte_storage_size() - calculate the memory occupied by compressed tags. + * @handle: storage handle returned by mte_compress. + * + * Returns: size of the storage used for @handle. + */ +size_t mte_storage_size(unsigned long handle) +{ + if (mte_is_inline(handle)) + return 8; + return mte_cache_id_to_size(handle & MTE_CACHE_ID_MASK); +} +EXPORT_SYMBOL_NS(mte_storage_size, MTECOMP); + +static void mte_bitmap_write(unsigned long *bitmap, unsigned long value, + unsigned long *pos, unsigned long bits) +{ + bitmap_write(bitmap, value, *pos, bits); + *pos += bits; +} + +static inline unsigned long mte_largest_idx_bits(size_t size) +{ + if (size == 8) + return MTE_BITS_PER_LARGEST_IDX_INLINE; + return MTE_BITS_PER_LARGEST_IDX; +} + +/* Compress ranges into the buffer that can accommodate up to max_ranges. */ +static void mte_compress_to_buf(size_t len, u8 *tags, unsigned short *sizes, + unsigned long *bitmap, size_t size) +{ + unsigned long bit_pos = 0, l_bits; + unsigned int largest_idx, i; + unsigned short largest = 0; + size_t max_ranges; + + for (i = 0; i < len; i++) { + if (sizes[i] > largest) { + largest = sizes[i]; + largest_idx = i; + } + } + l_bits = mte_largest_idx_bits(size); + max_ranges = mte_size_to_ranges(size); + mte_bitmap_write(bitmap, largest_idx, &bit_pos, l_bits); + for (i = 0; i < len; i++) + mte_bitmap_write(bitmap, tags[i], &bit_pos, MTE_TAG_SIZE); + for (i = len; i < max_ranges; i++) + mte_bitmap_write(bitmap, 0, &bit_pos, MTE_TAG_SIZE); + for (i = 0; i < len; i++) { + if (i != largest_idx) + mte_bitmap_write(bitmap, sizes[i], &bit_pos, + MTE_BITS_PER_SIZE); + } + for (i = len; i < max_ranges; i++) + mte_bitmap_write(bitmap, 0, &bit_pos, MTE_BITS_PER_SIZE); +} + +/** + * mte_compress() - compress the given tag array. + * @tags: MTE_GRANULES_PER_PAGE-byte array to read the tags from. + * + * Compresses the tags and returns a 64-bit opaque handle pointing to the + * tag storage. May allocate memory, which is freed by @mte_release_handle(). + * + * Returns: 64-bit tag storage handle. + */ +unsigned long mte_compress(u8 *tags) +{ + struct kmem_cache *cache; + unsigned short *r_sizes; + unsigned long *storage; + unsigned int cache_id; + size_t alloc_size; + u8 *r_tags; + size_t r_len; + /* + * mte_compress_to_buf() only initializes the bits that mte_decompress() + * will read. But when the tags are stored in the handle itself, it must + * have all its bits initialized. + */ + unsigned long result = 0; + + r_sizes = kmalloc_array(MTE_GRANULES_PER_PAGE, sizeof(unsigned short), + GFP_KERNEL); + r_tags = kmalloc(MTE_GRANULES_PER_PAGE, GFP_KERNEL); + if (!r_sizes || !r_tags) + goto ret; + r_len = MTE_GRANULES_PER_PAGE; + mte_tags_to_ranges(tags, r_tags, r_sizes, &r_len); + alloc_size = mte_alloc_size(r_len); + if (alloc_size == 8) { + mte_compress_to_buf(r_len, r_tags, r_sizes, &result, + alloc_size); + atomic_long_inc(&alloc_counters[0]); + goto ret; + } + cache_id = mte_size_to_cache_id(alloc_size); + cache = mtecomp_caches[cache_id]; + storage = kmem_cache_alloc(cache, GFP_KERNEL); + atomic_long_inc(&alloc_counters[cache_id + 1]); + if (!storage) { + result = 0; + goto ret; + } + if (alloc_size < MTE_PAGE_TAG_STORAGE) { + /* alloc_size is always a multiple of sizeof(unsigned long). */ + mte_compress_to_buf(r_len, r_tags, r_sizes, storage, + alloc_size); + result = ((unsigned long)storage | cache_id) & MTE_HANDLE_MASK; + goto ret; + } + memcpy(storage, tags, alloc_size); + result = ((unsigned long)storage | cache_id) & MTE_HANDLE_MASK; +ret: + kfree(r_tags); + kfree(r_sizes); + return result; +} +EXPORT_SYMBOL_NS(mte_compress, MTECOMP); + +static unsigned long mte_bitmap_read(const unsigned long *bitmap, + unsigned long *pos, unsigned long bits) +{ + unsigned long start = *pos; + + *pos += bits; + return bitmap_read(bitmap, start, bits); +} + +/* Decompress the contents of the given buffer into @tags. */ +static bool mte_decompress_from_buf(const unsigned long *bitmap, size_t size, + u8 *tags) +{ + unsigned long bit_pos = 0, l_bits; + unsigned short *r_sizes, sum; + unsigned int largest_idx, i; + bool result = true; + size_t max_ranges; + u8 *r_tags; + + max_ranges = mte_size_to_ranges(size); + l_bits = mte_largest_idx_bits(size); + largest_idx = mte_bitmap_read(bitmap, &bit_pos, l_bits); + r_sizes = kmalloc_array(max_ranges, sizeof(unsigned short), GFP_KERNEL); + r_tags = kmalloc(max_ranges, GFP_KERNEL); + if (!r_sizes || !r_tags) { + result = false; + goto ret; + } + + for (i = 0; i < max_ranges; i++) + r_tags[i] = mte_bitmap_read(bitmap, &bit_pos, MTE_TAG_SIZE); + for (i = 0, sum = 0; i < max_ranges; i++) { + if (i == largest_idx) + continue; + r_sizes[i] = + mte_bitmap_read(bitmap, &bit_pos, MTE_BITS_PER_SIZE); + if (!r_sizes[i]) { + max_ranges = i; + break; + } + sum += r_sizes[i]; + } + if (sum >= MTE_GRANULES_PER_PAGE) { + result = false; + goto ret; + } + r_sizes[largest_idx] = MTE_GRANULES_PER_PAGE - sum; + mte_ranges_to_tags(r_tags, r_sizes, max_ranges, tags); + result = true; +ret: + kfree(r_sizes); + kfree(r_tags); + return result; +} + +/* Get pointer to the out-of-line storage from a handle. */ +static void *mte_storage(unsigned long handle) +{ + if (mte_is_inline(handle)) + return NULL; + return (void *)((handle & (~MTE_CACHE_ID_MASK)) | BIT_ULL(63)); +} + +/** + * mte_decompress() - decompress the tag array addressed by the handle. + * @handle: handle returned by @mte_decompress() + * @tags: MTE_GRANULES_PER_PAGE-byte array to write the tags to. + * + * Reads the compressed data and writes it into the user-supplied tag array. + * + * Returns: true on success, false on error. + */ +bool mte_decompress(unsigned long handle, u8 *tags) +{ + unsigned long *storage = mte_storage(handle); + size_t size = mte_storage_size(handle); + + switch (size) { + case 8: + return mte_decompress_from_buf(&handle, size, tags); + case MTE_PAGE_TAG_STORAGE: + memcpy(tags, storage, size); + return true; + default: + return mte_decompress_from_buf(storage, size, tags); + } +} +EXPORT_SYMBOL_NS(mte_decompress, MTECOMP); + +/** + * mte_release_handle() - release the handle returned by mte_compress(). + * @handle: handle returned by mte_compress(). + */ +void mte_release_handle(unsigned long handle) +{ + unsigned int cache_id; + struct kmem_cache *c; + void *storage; + size_t size; + + storage = mte_storage(handle); + if (!storage) { + atomic_long_inc(&dealloc_counters[0]); + return; + } + + size = mte_storage_size(handle); + cache_id = mte_size_to_cache_id(size); + c = mtecomp_caches[cache_id]; + kmem_cache_free(c, storage); + atomic_long_inc(&dealloc_counters[cache_id + 1]); +} +EXPORT_SYMBOL_NS(mte_release_handle, MTECOMP); + +/* DebugFS interface. */ +static int stats_show(struct seq_file *seq, void *v) +{ + unsigned long total_mem_alloc = 0, total_mem_dealloc = 0; + unsigned long total_num_alloc = 0, total_num_dealloc = 0; + unsigned long size = 8; + long alloc, dealloc; + int i; + + for (i = 0; i <= MTECOMP_NUM_CACHES; i++) { + alloc = atomic_long_read(&alloc_counters[i]); + dealloc = atomic_long_read(&dealloc_counters[i]); + total_num_alloc += alloc; + total_num_dealloc += dealloc; + /* + * Do not count 8-byte buffers towards compressed tag storage + * size. + */ + if (i) { + total_mem_alloc += (size * alloc); + total_mem_dealloc += (size * dealloc); + } + seq_printf(seq, + "%lu bytes: %lu allocations, %lu deallocations\n", + size, alloc, dealloc); + size <<= 1; + } + seq_printf(seq, "uncompressed tag storage size: %lu\n", + (total_num_alloc - total_num_dealloc) * + MTE_PAGE_TAG_STORAGE); + seq_printf(seq, "compressed tag storage size: %lu\n", + total_mem_alloc - total_mem_dealloc); + return 0; +} +DEFINE_SHOW_ATTRIBUTE(stats); + +static int mtecomp_debugfs_init(void) +{ + struct dentry *mtecomp_dir; + + mtecomp_dir = debugfs_create_dir("mtecomp", NULL); + debugfs_create_file("stats", 0444, mtecomp_dir, NULL, &stats_fops); + return 0; +} + +/* Set up mtecomp_caches[]. */ +static int mtecomp_init(void) +{ + unsigned int i; + char name[16]; + size_t size; + + static_assert(MTECOMP_NUM_CACHES <= (MTE_CACHE_ID_MASK + 1)); + for (i = 0; i < MTECOMP_NUM_CACHES; i++) { + size = mte_cache_id_to_size(i); + snprintf(name, sizeof(name), "mte-tags-%ld", size); + mtecomp_caches[i] = + kmem_cache_create(name, size, size, 0, NULL); + } + mtecomp_debugfs_init(); + return 0; +} +module_init(mtecomp_init); diff --git a/arch/arm64/mm/mtecomp.h b/arch/arm64/mm/mtecomp.h new file mode 100644 index 0000000000000..b94cf0384f2af --- /dev/null +++ b/arch/arm64/mm/mtecomp.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef ARCH_ARM64_MM_MTECOMP_H_ +#define ARCH_ARM64_MM_MTECOMP_H_ + +/* Functions exported from mtecomp.c for test_mtecomp.c. */ +void mte_tags_to_ranges(u8 *tags, u8 *out_tags, unsigned short *out_sizes, + size_t *out_len); +void mte_ranges_to_tags(u8 *r_tags, unsigned short *r_sizes, size_t r_len, + u8 *tags); + +#endif // ARCH_ARM64_MM_TEST_MTECOMP_H_ From patchwork Fri Sep 22 08:08:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 143255 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5405592vqi; Fri, 22 Sep 2023 01:25:45 -0700 (PDT) X-Google-Smtp-Source: AGHT+IELmvnin3gSD2PcrLYtfSNDP/wdJrBiMyEKo2dFFOgoKkBlQr12Toa5Grb0+E5DEAkg/6jx X-Received: by 2002:a05:6a00:1508:b0:690:b7a1:ac51 with SMTP id q8-20020a056a00150800b00690b7a1ac51mr7804371pfu.31.1695371144947; Fri, 22 Sep 2023 01:25:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1695371144; cv=none; d=google.com; s=arc-20160816; b=ea6+VcslHrwJvsGlENnB1t2xU1iYN/LexiuimMBAD8hXrChcXiR5Qw8Cs7Jn8U4Yzs zPtmI5hoZJ2sKEpFwAB2JJO9kRpN+DgW0h3wZjiDdyld0vMACHIqp9IOWSoNPIlb3Sou p8HtNzVcyYQYxhM6r0hi0MNw2iWoPwTCsNVwz1hm0WDGzkMrG9f8eBCiaTkXfem7XVRU p+LSppE11wVpVQECkMHNM1V94dURF+ZrG9FKHtYJhqwJm8v4DZKhT9fTmQSBNOxw43rO ztSalkzTyqpOo3+8HIoS3od4HUGt1OWnP1Gok9GTNth7winc9P9qPi0ZH7VtpdXUQzd6 klVw== ARC-Message-Signature: i=1; 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[23.128.96.37]) by mx.google.com with ESMTPS id a21-20020a63e855000000b0057d7cff25c7si415435pgk.417.2023.09.22.01.25.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 01:25:44 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=3ygtYUtK; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id 935F783B95D0; Fri, 22 Sep 2023 01:09:31 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232220AbjIVIJU (ORCPT + 30 others); Fri, 22 Sep 2023 04:09:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232253AbjIVIJM (ORCPT ); Fri, 22 Sep 2023 04:09:12 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A24DC10C7 for ; Fri, 22 Sep 2023 01:09:03 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-59bf37b7734so28036767b3.0 for ; Fri, 22 Sep 2023 01:09:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695370143; x=1695974943; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=9QO5mfEasjHX0NR/arjcV00dOpfY7EEoHsjugtLpi5E=; b=3ygtYUtKm0+6DI6L77n3qMjKRHcaJVA/dwq5QdssB6VftHUSUu2xs1gjBxanZZsfg+ ipIJjGJZMKNutVYKNKiEb2iwmM7dftlbp7+6Vhn+GptdOPpH/nEAE+CXamrbUAE59ywL xj0Hn07XkQ7hq9y1nsgRldk+rOipsl2TpLKRThK7cP4q0uIXJRkEBOUmsCcRKrTeRX5L NwuKrB1kxB3neQX8Ejnuo1SZ1XJPvTrmR4tF38YCideNvsB3cXi+mRyBsJVsXnhcAavZ 1Q/g+xWwoHHN/Qp+2prtvPxgn7t4eQ9+D9xoKL2192x/iL7YH/h0WQp5KOVRn9rPJFfX lyUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695370143; x=1695974943; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9QO5mfEasjHX0NR/arjcV00dOpfY7EEoHsjugtLpi5E=; b=cAaaIhtCidbYIEtkPdV8JLAiKHU+1HKtvUkkHo6LQbk/6HAml61pjBUTqdXWx8EWoT u3cq0uYqHKF2AdvLevLKoi/LCRqW7qsATfrS/pj52Jainr0JmI0tN25TFfz4H+CAr0Zk sK1ljE3r6U6kWZgXCpE0NsMH4kZhiwPqL2BBlpXCqadGbJLgdTBVKC5NVQBT6KBf2FgT PcLWedolEhQTHZ5akCwwRKjP4DAztTCpuyzboiew+zPyTdSk0v4dh5cnsnqUdVlrACoB cnQESvKjjnO6s74NSbKMXZWf6/eZR1Y75DvSLUsnq6S4FkB/Cxf9sOFJSr1fD72xbk5l iq2Q== X-Gm-Message-State: AOJu0Yw6XT1S56QgvBIMrwlwH9gMnbeJX4U1TWtWt9JfB9Ce1IbY3Vz9 MbrklWdG8bC1MTE4j4NIaHdctEkatOs= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:4da0:80d4:9480:7d5c]) (user=glider job=sendgmr) by 2002:a81:d105:0:b0:59c:b9b:8940 with SMTP id w5-20020a81d105000000b0059c0b9b8940mr116755ywi.8.1695370142882; Fri, 22 Sep 2023 01:09:02 -0700 (PDT) Date: Fri, 22 Sep 2023 10:08:46 +0200 In-Reply-To: <20230922080848.1261487-1-glider@google.com> Mime-Version: 1.0 References: <20230922080848.1261487-1-glider@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230922080848.1261487-5-glider@google.com> Subject: [PATCH v5 4/5] arm64: mte: add a test for MTE tags compression From: Alexander Potapenko To: glider@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Fri, 22 Sep 2023 01:09:31 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777725493789012977 X-GMAIL-MSGID: 1777725493789012977 Ensure that tag sequences containing alternating values are compressed to buffers of expected size and correctly decompressed afterwards. Signed-off-by: Alexander Potapenko --- v5: - remove hardcoded constants, added test setup/teardown; - support 16- and 64K pages; - replace nested if-clauses with expected_size_from_ranges(); - call mte_release_handle() after tests that perform compression/decompression; - address comments by Andy Shevchenko: - fix include order; - use mtecomp.h instead of function prototypes. v4: - addressed comments by Andy Shevchenko: - expanded MTE to "Memory Tagging Extension" in Kconfig - changed signed variables to unsigned where applicable - added missing header dependencies - addressed comments by Yury Norov: - moved test-only declarations from mtecomp.h into this test - switched to the new "mte"-prefixed function names, dropped the mentions of "EA0" - added test_tag_to_ranges_n() v3: - addressed comments by Andy Shevchenko in another patch: - switched from u64 to unsigned long - added MODULE_IMPORT_NS(MTECOMP) - fixed includes order --- arch/arm64/Kconfig | 10 ++ arch/arm64/mm/Makefile | 1 + arch/arm64/mm/test_mtecomp.c | 287 +++++++++++++++++++++++++++++++++++ 3 files changed, 298 insertions(+) create mode 100644 arch/arm64/mm/test_mtecomp.c diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index d4fb3b8d11d77..ffe3bec89df82 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2104,6 +2104,16 @@ config ARM64_MTE_COMP RLE to conserve heap memory. In the common case compressed tags occupy 2.5x less memory. +config ARM64_MTE_COMP_KUNIT_TEST + tristate "Test tag compression for ARM64 Memory Tagging Extension" if !KUNIT_ALL_TESTS + default KUNIT_ALL_TESTS + depends on KUNIT && ARM64_MTE_COMP + help + Test MTE compression algorithm enabled by CONFIG_ARM64_MTE_COMP. + + Ensure that tag sequences containing alternating values are compressed + to buffers of expected size and correctly decompressed afterwards. + config ARM64_SVE bool "ARM Scalable Vector Extension support" default y diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 46778f6dd83c2..170dc62b010b9 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_TRANS_TABLE) += trans_pgd-asm.o obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o obj-$(CONFIG_ARM64_MTE) += mteswap.o obj-$(CONFIG_ARM64_MTE_COMP) += mtecomp.o +obj-$(CONFIG_ARM64_MTE_COMP_KUNIT_TEST) += test_mtecomp.o KASAN_SANITIZE_physaddr.o += n obj-$(CONFIG_KASAN) += kasan_init.o diff --git a/arch/arm64/mm/test_mtecomp.c b/arch/arm64/mm/test_mtecomp.c new file mode 100644 index 0000000000000..2a4a53daa7b1b --- /dev/null +++ b/arch/arm64/mm/test_mtecomp.c @@ -0,0 +1,287 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for MTE tags compression algorithm. + */ + +#include +#include +#include +#include +#include + +#include + +#include + +#include "mtecomp.h" + +/* Per-test storage allocated in mtecomp_test_init(). */ +struct test_data { + u8 *tags, *dtags; + unsigned short *r_sizes; + size_t r_len; + u8 *r_tags; +}; + +/* + * Split td->tags to ranges stored in td->r_tags, td->r_sizes, td->r_len, + * then convert those ranges back to tags stored in td->dtags. + */ +static void tags_to_ranges_to_tags_helper(struct kunit *test) +{ + struct test_data *td = test->priv; + + mte_tags_to_ranges(td->tags, td->r_tags, td->r_sizes, &td->r_len); + mte_ranges_to_tags(td->r_tags, td->r_sizes, td->r_len, td->dtags); + KUNIT_EXPECT_EQ(test, memcmp(td->tags, td->dtags, MTE_PAGE_TAG_STORAGE), + 0); +} + +/* + * Test that mte_tags_to_ranges() produces a single range for a zero-filled tag + * buffer. + */ +static void test_tags_to_ranges_zero(struct kunit *test) +{ + struct test_data *td = test->priv; + + memset(td->tags, 0, MTE_PAGE_TAG_STORAGE); + tags_to_ranges_to_tags_helper(test); + + KUNIT_EXPECT_EQ(test, td->r_len, 1); + KUNIT_EXPECT_EQ(test, td->r_tags[0], 0); + KUNIT_EXPECT_EQ(test, td->r_sizes[0], MTE_GRANULES_PER_PAGE); +} + +/* + * Test that a small number of different tags is correctly transformed into + * ranges. + */ +static void test_tags_to_ranges_simple(struct kunit *test) +{ + struct test_data *td = test->priv; + const u8 ex_tags[] = { 0xa, 0x0, 0xa, 0xb, 0x0 }; + const unsigned short ex_sizes[] = { 1, 2, 2, 1, + MTE_GRANULES_PER_PAGE - 6 }; + + memset(td->tags, 0, MTE_PAGE_TAG_STORAGE); + td->tags[0] = 0xa0; + td->tags[1] = 0x0a; + td->tags[2] = 0xab; + tags_to_ranges_to_tags_helper(test); + + KUNIT_EXPECT_EQ(test, td->r_len, 5); + KUNIT_EXPECT_EQ(test, memcmp(td->r_tags, ex_tags, sizeof(ex_tags)), 0); + KUNIT_EXPECT_EQ(test, memcmp(td->r_sizes, ex_sizes, sizeof(ex_sizes)), + 0); +} + +/* Test that repeated 0xa0 byte produces MTE_GRANULES_PER_PAGE ranges of length 1. */ +static void test_tags_to_ranges_repeated(struct kunit *test) +{ + struct test_data *td = test->priv; + + memset(td->tags, 0xa0, MTE_PAGE_TAG_STORAGE); + tags_to_ranges_to_tags_helper(test); + + KUNIT_EXPECT_EQ(test, td->r_len, MTE_GRANULES_PER_PAGE); +} + +/* Generate a buffer that will contain @nranges of tag ranges. */ +static void gen_tag_range_helper(u8 *tags, int nranges) +{ + unsigned int i; + + memset(tags, 0, MTE_PAGE_TAG_STORAGE); + if (nranges > 1) { + nranges--; + for (i = 0; i < nranges / 2; i++) + tags[i] = 0xab; + if (nranges % 2) + tags[nranges / 2] = 0xa0; + } +} + +/* + * Test that mte_tags_to_ranges()/mte_ranges_to_tags() work for various + * r_len values. + */ +static void test_tag_to_ranges_n(struct kunit *test) +{ + struct test_data *td = test->priv; + unsigned int i, j, sum; + + for (i = 1; i <= MTE_GRANULES_PER_PAGE; i++) { + gen_tag_range_helper(td->tags, i); + tags_to_ranges_to_tags_helper(test); + sum = 0; + for (j = 0; j < td->r_len; j++) + sum += td->r_sizes[j]; + KUNIT_EXPECT_EQ(test, sum, MTE_GRANULES_PER_PAGE); + } +} + +/* + * Check that the tag buffer in test->priv can be compressed and decompressed + * without changes. + */ +static unsigned long compress_decompress_helper(struct kunit *test) +{ + struct test_data *td = test->priv; + unsigned long handle; + + handle = mte_compress(td->tags); + KUNIT_EXPECT_EQ(test, handle & BIT_ULL(63), 0); + KUNIT_EXPECT_TRUE(test, mte_decompress(handle, td->dtags)); + KUNIT_EXPECT_EQ(test, memcmp(td->tags, td->dtags, MTE_PAGE_TAG_STORAGE), + 0); + return handle; +} + +/* Test that a zero-filled array is compressed into inline storage. */ +static void test_compress_zero(struct kunit *test) +{ + struct test_data *td = test->priv; + unsigned long handle; + + memset(td->tags, 0, MTE_PAGE_TAG_STORAGE); + handle = compress_decompress_helper(test); + /* Tags are stored inline. */ + KUNIT_EXPECT_EQ(test, mte_storage_size(handle), 8); + mte_release_handle(handle); +} + +/* + * Test that a very small number of tag ranges ends up compressed into 8 bytes. + */ +static void test_compress_simple(struct kunit *test) +{ + struct test_data *td = test->priv; + unsigned long handle; + + memset(td->tags, 0, MTE_PAGE_TAG_STORAGE); + td->tags[0] = 0xa0; + td->tags[1] = 0x0a; + + handle = compress_decompress_helper(test); + /* Tags are stored inline. */ + KUNIT_EXPECT_EQ(test, mte_storage_size(handle), 8); + mte_release_handle(handle); +} + +/* + * Test that a buffer containing @nranges ranges compresses into @exp_size + * bytes and decompresses into the original tag sequence. + */ +static void compress_range_helper(struct kunit *test, int nranges, + size_t exp_size) +{ + struct test_data *td = test->priv; + unsigned long handle; + + gen_tag_range_helper(td->tags, nranges); + handle = compress_decompress_helper(test); + KUNIT_EXPECT_EQ(test, mte_storage_size(handle), exp_size); + mte_release_handle(handle); +} + +static size_t expected_size_from_ranges(unsigned int ranges) +{ +#if defined CONFIG_ARM64_4K_PAGES + unsigned int range_exp[4] = { 6, 11, 23, 46 }; +#elif defined(CONFIG_ARM64_16K_PAGES) + unsigned int range_exp[6] = { 5, 9, 19, 39, 78, 157 }; +#elif defined(CONFIG_ARM64_64K_PAGES) + unsigned int range_exp[8] = { 4, 8, 17, 34, 68, 136, 273, 546 }; +#endif + unsigned int i; + size_t size = 8; + + for (i = 0; i < ARRAY_SIZE(range_exp); i++) { + if (ranges <= range_exp[i]) + return size; + size <<= 1; + } + return size; +} + +/* + * Test that every number of tag ranges is correctly compressed and + * decompressed. + */ +static void test_compress_ranges(struct kunit *test) +{ + size_t exp_size; + unsigned int i; + + for (i = 1; i <= MTE_GRANULES_PER_PAGE; i++) { + exp_size = expected_size_from_ranges(i); + compress_range_helper(test, i, exp_size); + } +} + +static void mtecomp_dealloc_testdata(struct test_data *td) +{ + kfree(td->tags); + kfree(td->dtags); + kfree(td->r_sizes); + kfree(td->r_tags); +} + +static int mtecomp_test_init(struct kunit *test) +{ + struct test_data *td; + + td = kmalloc(sizeof(struct test_data), GFP_KERNEL); + if (!td) + return 1; + td->tags = kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL); + if (!td->tags) + goto error; + td->dtags = kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL); + if (!td->dtags) + goto error; + td->r_len = MTE_GRANULES_PER_PAGE; + td->r_sizes = kmalloc_array(MTE_GRANULES_PER_PAGE, + sizeof(unsigned short), GFP_KERNEL); + if (!td->r_sizes) + goto error; + td->r_tags = kmalloc(MTE_GRANULES_PER_PAGE, GFP_KERNEL); + if (!td->r_tags) + goto error; + test->priv = (void *)td; + return 0; +error: + mtecomp_dealloc_testdata(td); + return 1; +} + +static void mtecomp_test_exit(struct kunit *test) +{ + struct test_data *td = test->priv; + + mtecomp_dealloc_testdata(td); +} + +static struct kunit_case mtecomp_test_cases[] = { + KUNIT_CASE(test_tags_to_ranges_zero), + KUNIT_CASE(test_tags_to_ranges_simple), + KUNIT_CASE(test_tags_to_ranges_repeated), + KUNIT_CASE(test_tag_to_ranges_n), + KUNIT_CASE(test_compress_zero), + KUNIT_CASE(test_compress_simple), + KUNIT_CASE(test_compress_ranges), + {} +}; + +static struct kunit_suite mtecomp_test_suite = { + .name = "mtecomp", + .init = mtecomp_test_init, + .exit = mtecomp_test_exit, + .test_cases = mtecomp_test_cases, +}; +kunit_test_suites(&mtecomp_test_suite); + +MODULE_IMPORT_NS(MTECOMP); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alexander Potapenko "); From patchwork Fri Sep 22 08:08:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 143252 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:172:b0:3f2:4152:657d with SMTP id h50csp5404752vqi; Fri, 22 Sep 2023 01:23:32 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFy3J9XIbZIMl/DHMBBaq2AXmGVNF4pIKMNZRqQGclscWAdmNHZeeJcrDE8uKWHPsQe3yH0 X-Received: by 2002:a05:6a00:3493:b0:68f:c2f7:cef0 with SMTP id cp19-20020a056a00349300b0068fc2f7cef0mr3441819pfb.4.1695371012381; 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[2620:137:e000::3:8]) by mx.google.com with ESMTPS id s185-20020a632cc2000000b00573fb3325b3si3376623pgs.481.2023.09.22.01.23.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 01:23:32 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=RZo0FCRI; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by fry.vger.email (Postfix) with ESMTP id 7577C82F96AB; Fri, 22 Sep 2023 01:09:34 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232250AbjIVIJX (ORCPT + 30 others); Fri, 22 Sep 2023 04:09:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232383AbjIVIJO (ORCPT ); Fri, 22 Sep 2023 04:09:14 -0400 Received: from mail-wr1-x44a.google.com (mail-wr1-x44a.google.com [IPv6:2a00:1450:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C014CF2 for ; Fri, 22 Sep 2023 01:09:07 -0700 (PDT) Received: by mail-wr1-x44a.google.com with SMTP id ffacd0b85a97d-32310ab48f2so31646f8f.3 for ; Fri, 22 Sep 2023 01:09:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695370146; x=1695974946; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=UdOlGrvM1GssuaeVLKYkN4jxEWq2ZAaVfQMqqTCAZPM=; b=RZo0FCRIZTd/3al/hMY9fxzicTRqiqXtu+oK102HDjPrExohurwql/+LxK7Ttsle+W OghIEwVLx/by/QsXzE2tSuaiLkwScX+MjNh0MTQThx/gzDKZnDWZV4/a1XzGm2jzrVB1 btGJJMmzVPO3INXUiPfWsuztb1gfdk0tvgJFnEqNJxBsTjoPAbGfnQ6mCW8+B70RCgga Ud6KWq/NOCSNpD2fP30gTl2nMoD+kvOnsfJl02Zln56rTh+N91OFUdrz/CT4L52f8m3X bOHWVfCLNVY0OrdgUHC+IOJlC8XlroVSMvwaxEBvpc/dcTIY5zEd6uU6T7VW4diuj7O9 JskA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695370146; x=1695974946; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=UdOlGrvM1GssuaeVLKYkN4jxEWq2ZAaVfQMqqTCAZPM=; b=W77AMfTO6UQS77+cCuNCNolMuBnWVtzPA1EgHoZuMWwd4JPYRaNApvTkeaXfKQRQgJ g6c16GTZU6hNyqZhSudXfrZ2S4pGX3L9GoGDuuBrNhSLyQ/fE8i00aVMZcdmyf85GgOX qrTbKEVFw9omANXo7Ue2HA+KjxxIdjDIaEruI8czcQfbK2d5IGOM8Cnc7+Uz+u61Pc0f MTpmgt/wrRP/b4h0+xyGTarilheh3wB6/j/JIRwKT4o/MucOHxriTVWhnCZmJhKUtUYy 35rmaTI2ugX5SfdUIYd6jcXI5WwnAK54s/fHxyTbwpSbUXhKTCLwXO44Gv18BIAEiwM6 r30A== X-Gm-Message-State: AOJu0Yz+lkuJPDtAdWpBfIVy4reNA6H3xJ2TxENRLDfV4tcz0fuTSdgO 6kujsBlKsBLzO6SbOiTGH02KRCNfpjg= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:4da0:80d4:9480:7d5c]) (user=glider job=sendgmr) by 2002:a5d:43ce:0:b0:317:f046:25e6 with SMTP id v14-20020a5d43ce000000b00317f04625e6mr48761wrr.2.1695370145494; Fri, 22 Sep 2023 01:09:05 -0700 (PDT) Date: Fri, 22 Sep 2023 10:08:47 +0200 In-Reply-To: <20230922080848.1261487-1-glider@google.com> Mime-Version: 1.0 References: <20230922080848.1261487-1-glider@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230922080848.1261487-6-glider@google.com> Subject: [PATCH v5 5/5] arm64: mte: add compression support to mteswap.c From: Alexander Potapenko To: glider@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org X-Spam-Status: No, score=-8.4 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (fry.vger.email [0.0.0.0]); Fri, 22 Sep 2023 01:09:34 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777725354824376680 X-GMAIL-MSGID: 1777725354824376680 Define the internal mteswap.h interface: - _mte_alloc_and_save_tags() - _mte_free_saved_tags() - _mte_restore_tags() , that encapsulates saving tags for a struct page (together with memory allocation), restoring tags, and deleting the storage allocated for them. These functions accept opaque pointers, which may point to tag buffers of size MTE_PAGE_TAG_STORAGE, as well as smaller buffers containing compressed tags, or may have compressed tags stored directly in the pointers. The existing code from mteswap.c operating with uncompressed tags is split away into mteswap_nocomp.c, and the newly introduced mteswap_comp.c provides compression support. The latter implementation is picked if CONFIG_ARM64_MTE_COMP=y. Soon after booting Android, tag compression saves ~2.5x memory previously spent by mteswap.c on tag allocations. With the growing uptime, the savings may reach 4x and even more. On a moderately loaded device with ~20% pages using tagging, the compressed tags for swapped pages only occupied 2.9Mb instead of 16.5Mb: 8 bytes: 118277 allocations, 16089 deallocations 16 bytes: 10762 allocations, 6738 deallocations 32 bytes: 10748 allocations, 6823 deallocations 64 bytes: 10510 allocations, 6644 deallocations 128 bytes: 68375 allocations, 47378 deallocations uncompressed tag storage size: 17280000 compressed tag storage size: 3125024 Signed-off-by: Alexander Potapenko --- v5: - drop a dead variable from _mte_free_saved_tags() in mteswap_comp.c - ensure MTE compression works with arbitrary page sizes - update patch description v4: - minor code simplifications suggested by Andy Shevchenko, added missing header dependencies - changed compression API names to reflect modifications made to memcomp.h (as suggested by Yury Norov) v3: - Addressed comments by Andy Shevchenko in another patch: - fixed includes order - replaced u64 with unsigned long - added MODULE_IMPORT_NS(MTECOMP) --- arch/arm64/mm/Makefile | 5 +++ arch/arm64/mm/mteswap.c | 20 +++++------- arch/arm64/mm/mteswap.h | 12 +++++++ arch/arm64/mm/mteswap_comp.c | 60 ++++++++++++++++++++++++++++++++++ arch/arm64/mm/mteswap_nocomp.c | 38 +++++++++++++++++++++ 5 files changed, 124 insertions(+), 11 deletions(-) create mode 100644 arch/arm64/mm/mteswap.h create mode 100644 arch/arm64/mm/mteswap_comp.c create mode 100644 arch/arm64/mm/mteswap_nocomp.c diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 170dc62b010b9..46a798e2b67cb 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -11,6 +11,11 @@ obj-$(CONFIG_TRANS_TABLE) += trans_pgd-asm.o obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o obj-$(CONFIG_ARM64_MTE) += mteswap.o obj-$(CONFIG_ARM64_MTE_COMP) += mtecomp.o +ifdef CONFIG_ARM64_MTE_COMP +obj-$(CONFIG_ARM64_MTE) += mteswap_comp.o +else +obj-$(CONFIG_ARM64_MTE) += mteswap_nocomp.o +endif obj-$(CONFIG_ARM64_MTE_COMP_KUNIT_TEST) += test_mtecomp.o KASAN_SANITIZE_physaddr.o += n diff --git a/arch/arm64/mm/mteswap.c b/arch/arm64/mm/mteswap.c index cd508ba80ab1b..9d8f87fd191a2 100644 --- a/arch/arm64/mm/mteswap.c +++ b/arch/arm64/mm/mteswap.c @@ -5,8 +5,11 @@ #include #include #include + #include +#include "mteswap.h" + static DEFINE_XARRAY(mte_pages); void *mte_allocate_tag_storage(void) @@ -27,20 +30,18 @@ int mte_save_tags(struct page *page) if (!page_mte_tagged(page)) return 0; - tag_storage = mte_allocate_tag_storage(); + tag_storage = _mte_alloc_and_save_tags(page); if (!tag_storage) return -ENOMEM; - mte_save_page_tags(page_address(page), tag_storage); - /* page_private contains the swap entry.val set in do_swap_page */ ret = xa_store(&mte_pages, page_private(page), tag_storage, GFP_KERNEL); if (WARN(xa_is_err(ret), "Failed to store MTE tags")) { - mte_free_tag_storage(tag_storage); + _mte_free_saved_tags(tag_storage); return xa_err(ret); } else if (ret) { /* Entry is being replaced, free the old entry */ - mte_free_tag_storage(ret); + _mte_free_saved_tags(ret); } return 0; @@ -53,10 +54,7 @@ void mte_restore_tags(swp_entry_t entry, struct page *page) if (!tags) return; - if (try_page_mte_tagging(page)) { - mte_restore_page_tags(page_address(page), tags); - set_page_mte_tagged(page); - } + _mte_restore_tags(tags, page); } void mte_invalidate_tags(int type, pgoff_t offset) @@ -64,7 +62,7 @@ void mte_invalidate_tags(int type, pgoff_t offset) swp_entry_t entry = swp_entry(type, offset); void *tags = xa_erase(&mte_pages, entry.val); - mte_free_tag_storage(tags); + _mte_free_saved_tags(tags); } void mte_invalidate_tags_area(int type) @@ -78,7 +76,7 @@ void mte_invalidate_tags_area(int type) xa_lock(&mte_pages); xas_for_each(&xa_state, tags, last_entry.val - 1) { __xa_erase(&mte_pages, xa_state.xa_index); - mte_free_tag_storage(tags); + _mte_free_saved_tags(tags); } xa_unlock(&mte_pages); } diff --git a/arch/arm64/mm/mteswap.h b/arch/arm64/mm/mteswap.h new file mode 100644 index 0000000000000..4c576b76785d1 --- /dev/null +++ b/arch/arm64/mm/mteswap.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef ARCH_ARM64_MM_MTESWAP_H_ +#define ARCH_ARM64_MM_MTESWAP_H_ + +struct page; + +void *_mte_alloc_and_save_tags(struct page *page); +void _mte_free_saved_tags(void *tags); +void _mte_restore_tags(void *tags, struct page *page); + +#endif // ARCH_ARM64_MM_MTESWAP_H_ diff --git a/arch/arm64/mm/mteswap_comp.c b/arch/arm64/mm/mteswap_comp.c new file mode 100644 index 0000000000000..4c628405822ce --- /dev/null +++ b/arch/arm64/mm/mteswap_comp.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* MTE tag storage management with compression. */ + +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "mteswap.h" + +void *_mte_alloc_and_save_tags(struct page *page) +{ + unsigned long handle; + u8 *tags; + + tags = mte_allocate_tag_storage(); + if (!tags) + return xa_mk_value(0); + mte_save_page_tags(page_address(page), tags); + handle = mte_compress(tags); + mte_free_tag_storage(tags); + return xa_mk_value(handle); +} + +void _mte_free_saved_tags(void *storage) +{ + unsigned long handle; + + handle = xa_to_value(storage); + if (!handle) + return; + mte_release_handle(handle); +} + +void _mte_restore_tags(void *tags, struct page *page) +{ + unsigned long handle; + u8 *tags_decomp; + + handle = xa_to_value(tags); + if (!handle) + return; + if (!try_page_mte_tagging(page)) + return; + tags_decomp = mte_allocate_tag_storage(); + if (!tags_decomp) + return; + if (!mte_decompress(handle, tags_decomp)) + return; + mte_restore_page_tags(page_address(page), tags_decomp); + set_page_mte_tagged(page); + mte_free_tag_storage(tags_decomp); +} +MODULE_IMPORT_NS(MTECOMP); diff --git a/arch/arm64/mm/mteswap_nocomp.c b/arch/arm64/mm/mteswap_nocomp.c new file mode 100644 index 0000000000000..1e665a4b5f940 --- /dev/null +++ b/arch/arm64/mm/mteswap_nocomp.c @@ -0,0 +1,38 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* MTE tag storage management without compression support. */ + +#include +#include +#include +#include +#include + +#include + +#include "mteswap.h" + +void *_mte_alloc_and_save_tags(struct page *page) +{ + void *storage; + + storage = mte_allocate_tag_storage(); + if (!storage) + return NULL; + + mte_save_page_tags(page_address(page), storage); + return storage; +} + +void _mte_free_saved_tags(void *storage) +{ + mte_free_tag_storage(storage); +} + +void _mte_restore_tags(void *tags, struct page *page) +{ + if (!try_page_mte_tagging(page)) + return; + mte_restore_page_tags(page_address(page), tags); + set_page_mte_tagged(page); +}