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| author |   Ard Biesheuvel <ardb@kernel.org> | 2025-01-01 12:51:20 +0100 |
|---|---|---|
| committer |   Borislav Petkov (AMD) <bp@alien8.de> | 2025-01-02 12:13:13 +0100 |
| commit | 99b863d2e87210c70354a1c75cc5bcc7a3afdc01 (patch) | |
| tree | 2fd6736087ae2340cbbafa918bcd872c6ae7caf3 | |
| parent | x86/boot/64: Fix spurious undefined reference when CONFIG_X86_5LEVEL=n, on GCC-12 (diff) | |
| download | wireguard-linux-99b863d2e87210c70354a1c75cc5bcc7a3afdc01.tar.xz wireguard-linux-99b863d2e87210c70354a1c75cc5bcc7a3afdc01.zip | |
x86/sev: Disable UBSAN on SEV code that may execute very early
Clang 14 and older may emit UBSAN instrumentation into code that is
inlined into functions marked with __no_sanitize_undefined¹. This may
result in faults when the code is executed very early, which may be the
case for functions annotated as __head. Now that this requirement is
strictly enforced, the build will fail in this case with the following
message
Absolute reference to symbol '.data' not permitted in .head.text
Work around this by disabling UBSAN instrumentation on all SEV core
code.
¹ https://lore.kernel.org/r/20250101024348.GA1828419@ax162
[ bp: Add a footnote with Nathan's detailed explanation and a Fixes
tag ]
Fixes: 3b6f99a94b04 ("x86/boot: Disable UBSAN in early boot code")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250101115119.114584-2-ardb@kernel.org
| -rw-r--r-- | arch/x86/coco/sev/Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/coco/sev/Makefile b/arch/x86/coco/sev/Makefile index 4e375e7305ac..08de37559307 100644 --- a/arch/x86/coco/sev/Makefile +++ b/arch/x86/coco/sev/Makefile @@ -13,3 +13,6 @@ KCOV_INSTRUMENT_core.o := n # With some compiler versions the generated code results in boot hangs, caused # by several compilation units. To be safe, disable all instrumentation. KCSAN_SANITIZE := n + +# Clang 14 and older may fail to respect __no_sanitize_undefined when inlining +UBSAN_SANITIZE := n |