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kstack_erase: Add -mgeneral-regs-only to silence Clang warnings

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Once CONFIG_KSTACK_ERASE is enabled with Clang on i386, the build warns:

  kernel/kstack_erase.c:168:2: warning: function with attribute 'no_caller_saved_registers' should only call a function with attribute 'no_caller_saved_registers' or be compiled with '-mgeneral-regs-only' [-Wexcessive-regsave]

Add -mgeneral-regs-only for the kstack_erase handler, to make Clang feel
better (it is effectively a no-op flag for the kernel). No binary
changes encountered.

Build & boot tested with Clang 21 on x86_64, and i386.
Build tested with GCC 14.2.0 on x86_64, i386, arm64, and arm.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20250726004313.GA3650901@ax162
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <kees@kernel.org>
This commit is contained in:
Kees Cook 2025-07-26 02:35:49 -07:00
parent 381a38ea53
commit 6676fd3c99
1 changed files with 1 additions and 0 deletions
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1
kernel/Makefile
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@ -140,6 +140,7 @@ obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o
obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o
CFLAGS_kstack_erase.o += $(DISABLE_KSTACK_ERASE)
CFLAGS_kstack_erase.o += $(call cc-option,-mgeneral-regs-only)
obj-$(CONFIG_KSTACK_ERASE) += kstack_erase.o
KASAN_SANITIZE_kstack_erase.o := n
KCSAN_SANITIZE_kstack_erase.o := n