diff mbox series

[35/46] Kbuild, lto: disable gcc LTO for bounds+asm-offsets

Message ID	20221114114344.18650-36-jirislaby@kernel.org
State	New
Headers	Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; From: "Jiri Slaby (SUSE)" <jirislaby@kernel.org> To: linux-kernel@vger.kernel.org Cc: Andi Kleen <andi@firstfloor.org>, Masahiro Yamada <masahiroy@kernel.org>, Michal Marek <michal.lkml@markovi.net>, Nick Desaulniers <ndesaulniers@google.com>, linux-kbuild@vger.kernel.org, Martin Liska <mliska@suse.cz>, Jiri Slaby <jslaby@suse.cz> Subject: [PATCH 35/46] Kbuild, lto: disable gcc LTO for bounds+asm-offsets Date: Mon, 14 Nov 2022 12:43:33 +0100 Message-Id: <20221114114344.18650-36-jirislaby@kernel.org> In-Reply-To: <20221114114344.18650-1-jirislaby@kernel.org> References: <20221114114344.18650-1-jirislaby@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	gcc-LTO support for the kernel \| [00/46] gcc-LTO support for the kernel [01/46] x86/boot: robustify calling startup_{32,64}() from the decompressor code [02/46] kbuild: pass jobserver to cmd_ld_vmlinux.o [03/46] kbuild: lto: preserve MAKEFLAGS for module linking [04/46] compiler.h: introduce __visible_on_lto [05/46] compiler.h: introduce __global_on_lto [06/46] Compiler Attributes, lto: introduce __noreorder [07/46] tracepoint, lto: Mark static call functions as __visible [08/46] static_call, lto: Mark static keys as __visible [09/46] static_call, lto: Mark static_call_return0() as __visible [10/46] static_call, lto: Mark func_a() as __visible_on_lto [11/46] x86/alternative, lto: Mark int3_() as global and __visible [12/46] x86/paravirt, lto: Mark native_steal_clock() as __visible_on_lto [13/46] x86/preempt, lto: Mark preempt_schedule_thunk() as __visible [14/46] x86/sev, lto: Mark cpuid_table_copy as __visible_on_lto [15/46] x86/xen, lto: Mark xen_vcpu_stolen() as __visible [16/46] x86, lto: Mark gdt_page and native_sched_clock() as __visible [17/46] amd, lto: Mark amd pmu and pstate functions as __visible_on_lto [18/46] entry, lto: Mark raw_irqentry_exit_cond_resched() as __visible [19/46] export, lto: Mark __kstrtab* in EXPORT_SYMBOL() as global and __visible [20/46] softirq, lto: Mark irq_enter/exit_rcu() as __visible [21/46] btf, lto: pass scope as strings [22/46] btf, lto: Make all BTF IDs global on LTO [23/46] init.h, lto: mark initcalls as __noreorder [24/46] bpf, lto: mark interpreter jump table as __noreorder [25/46] sched, lto: mark sched classes as __noreorder [26/46] x86/apic, lto: Mark apic_driver*() as __noreorder [27/46] linkage, lto: use C version for SYSCALL_ALIAS() / cond_syscall() [28/46] scripts, lto: re-add gcc-ld [29/46] scripts, lto: use CONFIG_LTO for many LTO specific actions [30/46] Kbuild, lto: Add Link Time Optimization support [31/46] x86/purgatory, lto: Disable gcc LTO for purgatory [32/46] x86/realmode, lto: Disable gcc LTO for real mode code [33/46] x86/vdso, lto: Disable gcc LTO for the vdso [34/46] scripts, lto: disable gcc LTO for some mod sources [35/46] Kbuild, lto: disable gcc LTO for bounds+asm-offsets [36/46] lib/string, lto: disable gcc LTO for string.o [37/46] Compiler attributes, lto: disable __flatten with LTO [38/46] Kbuild, lto: don't include weak source file symbols in System.map [39/46] x86, lto: Disable relative init pointers with gcc LTO [40/46] x86/livepatch, lto: Disable live patching with gcc LTO [41/46] x86/lib, lto: Mark 32bit mem{cpy,move,set} as __used [42/46] mm/kasan, lto: Mark kasan mem{cpy,move,set} as __used [43/46] scripts, lto: check C symbols for modversions [44/46] scripts/bloat-o-meter, lto: handle gcc LTO [45/46] kasan, lto: remove extra BUILD_BUG() in memory_is_poisoned [46/46] x86, lto: Finally enable gcc LTO for x86

Commit Message

Jiri Slaby Nov. 14, 2022, 11:43 a.m. UTC

  From: Andi Kleen <andi@firstfloor.org>

Disable LTO when generating the bounds+asm-offsets.s files which are
scanned for C constants. With a LTO build, the file would contain the
gcc IR in assembler form, which breaks the scanning scripts.

Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 Kbuild | 3 +++
 1 file changed, 3 insertions(+)

diff mbox series

Patch

diff --git a/Kbuild b/Kbuild
index 464b34a08f51..40744d76d416 100644
--- a/Kbuild
+++ b/Kbuild
@@ -11,6 +11,8 @@  bounds-file := include/generated/bounds.h
 
 targets := kernel/bounds.s
 
+kernel/bounds.s: KBUILD_CFLAGS += $(DISABLE_LTO_GCC)
+
 $(bounds-file): kernel/bounds.s FORCE
 	$(call filechk,offsets,__LINUX_BOUNDS_H__)
 
@@ -30,6 +32,7 @@  offsets-file := include/generated/asm-offsets.h
 targets += arch/$(SRCARCH)/kernel/asm-offsets.s
 
 arch/$(SRCARCH)/kernel/asm-offsets.s: $(timeconst-file) $(bounds-file)
+arch/$(SRCARCH)/kernel/asm-offsets.s: KBUILD_CFLAGS += $(DISABLE_LTO_GCC)
 
 $(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
 	$(call filechk,offsets,__ASM_OFFSETS_H__)