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[92.145.124.62]) by smtp.gmail.com with ESMTPSA id p9-20020a5d48c9000000b0031433443265sm18269448wrs.53.2023.08.02.01.12.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Aug 2023 01:12:11 -0700 (PDT) From: Alexandre Ghiti To: Jonathan Corbet , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Paul Walmsley , Palmer Dabbelt , Albert Ou , Atish Patra , Anup Patel , Will Deacon , Rob Herring , Andrew Jones , =?utf-8?q?R=C3=A9mi_Denis-Courmont?= , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Alexandre Ghiti Subject: [PATCH v6 08/10] Documentation: admin-guide: Add riscv sysctl_perf_user_access Date: Wed, 2 Aug 2023 10:03:26 +0200 Message-Id: <20230802080328.1213905-9-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230802080328.1213905-1-alexghiti@rivosinc.com> References: <20230802080328.1213905-1-alexghiti@rivosinc.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=unavailable 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-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1773106808345626221 X-GMAIL-MSGID: 1773106808345626221 riscv now uses this sysctl so document its usage for this architecture. Signed-off-by: Alexandre Ghiti --- Documentation/admin-guide/sysctl/kernel.rst | 27 ++++++++++++++++++--- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 3800fab1619b..8019103aac10 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -941,16 +941,35 @@ enabled, otherwise writing to this file will return ``-EBUSY``. The default value is 8. -perf_user_access (arm64 only) -================================= +perf_user_access (arm64 and riscv only) +======================================= + +Controls user space access for reading perf event counters. -Controls user space access for reading perf event counters. When set to 1, -user space can read performance monitor counter registers directly. +arm64 +===== The default value is 0 (access disabled). +When set to 1, user space can read performance monitor counter registers +directly. + See Documentation/arch/arm64/perf.rst for more information. +riscv +===== + +When set to 0, user space access is disabled. + +The default value is 1, user space can read performance monitor counter +registers through perf, any direct access without perf intervention will trigger +an illegal instruction. + +When set to 2, which enables legacy mode (user space has direct access to cycle +and insret CSRs only). Note that this legacy value is deprecated and will be +removed once all user space applications are fixed. + +Note that the time CSR is always directly accessible to all modes. pid_max =======