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| author | Borislav Petkov (AMD) <bp@alien8.de> | 2024-03-27 16:43:14 +0100 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-04-09 18:03:53 +0200 |
| commit | ee8962082a4413dba1a1b3d3d23490c5221f3b8a (patch) | |
| tree | 8a618545042e590d8f3e4e5b02b4a7e2a27e1b28 /arch | |
| parent | fec50db7033ea478773b159e0e2efb135270e3b7 (diff) | |
| download | linux-stable-ee8962082a4413dba1a1b3d3d23490c5221f3b8a.tar.gz linux-stable-ee8962082a4413dba1a1b3d3d23490c5221f3b8a.tar.bz2 linux-stable-ee8962082a4413dba1a1b3d3d23490c5221f3b8a.zip | |
x86/alternatives: Catch late X86_FEATURE modifiers
After alternatives have been patched, changes to the X86_FEATURE flags
won't take effect and could potentially even be wrong.
Warn about it.
This is something which has been long overdue.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Srikanth Aithal <sraithal@amd.com>
Link: https://lore.kernel.org/r/20240327154317.29909-3-bp@alien8.de
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/cpuid-deps.c | 3 |
2 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 686e92d2663e..f07687ddb13d 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -150,8 +150,12 @@ extern const char * const x86_bug_flags[NBUGINTS*32]; extern void setup_clear_cpu_cap(unsigned int bit); extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit); -#define setup_force_cpu_cap(bit) do { \ - set_cpu_cap(&boot_cpu_data, bit); \ +#define setup_force_cpu_cap(bit) do { \ + \ + if (!boot_cpu_has(bit)) \ + WARN_ON(alternatives_patched); \ + \ + set_cpu_cap(&boot_cpu_data, bit); \ set_bit(bit, (unsigned long *)cpu_caps_set); \ } while (0) diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c index b7174209d855..5dd427c6feb2 100644 --- a/arch/x86/kernel/cpu/cpuid-deps.c +++ b/arch/x86/kernel/cpu/cpuid-deps.c @@ -114,6 +114,9 @@ static void do_clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int feature) if (WARN_ON(feature >= MAX_FEATURE_BITS)) return; + if (boot_cpu_has(feature)) + WARN_ON(alternatives_patched); + clear_feature(c, feature); /* Collect all features to disable, handling dependencies */ |