summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorMark Rutland <mark.rutland@arm.com>2023-02-27 14:58:19 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2023-02-28 13:04:53 +0300
commitb3f11af9b2ce14d4662753d097a21e1d37a06fda (patch)
tree9048246847398ad970eedd3d68f153eb1b177d6b /arch
parent1b561d3949f8478c5403c9752b5533211a757226 (diff)
downloadlinux-b3f11af9b2ce14d4662753d097a21e1d37a06fda.tar.xz
arm64: ftrace: forbid CALL_OPS with CC_OPTIMIZE_FOR_SIZE
Florian reports that when building with CONFIG_CC_OPTIMIZE_FOR_SIZE=y, he sees "Misaligned patch-site" warnings at boot, e.g. | Misaligned patch-site bcm2836_arm_irqchip_handle_irq+0x0/0x88 | WARNING: CPU: 0 PID: 0 at arch/arm64/kernel/ftrace.c:120 ftrace_call_adjust+0x4c/0x70 This is because GCC will silently ignore `-falign-functions=N` when passed `-Os`, resulting in functions not being aligned as we expect. This is a known issue, and to account for this we modified the kernel to avoid `-Os` generally. Unfortunately we forgot to account for CONFIG_CC_OPTIMIZE_FOR_SIZE. Forbid the use of CALL_OPS with CONFIG_CC_OPTIMIZE_FOR_SIZE=y to prevent this issue. All exising ftrace features will work as before, though without the performance benefit of CALL_OPS. Reported-by: Florian Fainelli <f.fainelli@gmail.com> Link: http://lore.kernel.org/linux-arm-kernel/2d9284c3-3805-402b-5423-520ced56d047@gmail.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will@kernel.org> Tested-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20230227115819.365630-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/Kconfig3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 71c35178e017..f7521695a474 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -188,7 +188,8 @@ config ARM64
select HAVE_DYNAMIC_FTRACE_WITH_ARGS \
if $(cc-option,-fpatchable-function-entry=2)
select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
- if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG)
+ if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \
+ !CC_OPTIMIZE_FOR_SIZE)
select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
if DYNAMIC_FTRACE_WITH_ARGS
select HAVE_EFFICIENT_UNALIGNED_ACCESS