From: Michael Ellerman Date: Thu, 9 May 2024 12:12:48 +0000 (+1000) Subject: powerpc: Check only single values are passed to CPU/MMU feature checks X-Git-Tag: v6.11-rc1~96^2~4 X-Git-Url: https://repo.jachan.dev/linux.git/commitdiff_plain/db25a9625dbc3aa6613c0347f574689c248a3d0b powerpc: Check only single values are passed to CPU/MMU feature checks cpu_has_feature()/mmu_has_feature() are only able to check a single feature at a time, but there is no enforcement of that. In fact, as fixed in the previous commit, there was code that was passing multiple values to cpu_has_feature(). So add a check that only a single feature is passed using popcount. Note that the test allows 0 or 1 bits to be set, because some code relies on cpu_has_feature(0) being false, the check with CPU_FTRS_POSSIBLE ensures that. See for example CPU_FTR_PPC_LE. Signed-off-by: Michael Ellerman Link: https://msgid.link/20240509121248.270878-3-mpe@ellerman.id.au --- diff --git a/arch/powerpc/include/asm/cpu_has_feature.h b/arch/powerpc/include/asm/cpu_has_feature.h index 92e24e979954..bf8a228229fa 100644 --- a/arch/powerpc/include/asm/cpu_has_feature.h +++ b/arch/powerpc/include/asm/cpu_has_feature.h @@ -25,6 +25,7 @@ static __always_inline bool cpu_has_feature(unsigned long feature) int i; BUILD_BUG_ON(!__builtin_constant_p(feature)); + BUILD_BUG_ON(__builtin_popcountl(feature) > 1); #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG if (!static_key_feature_checks_initialized) { diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h index 1d1395b769a8..4182d68d9cd1 100644 --- a/arch/powerpc/include/asm/mmu.h +++ b/arch/powerpc/include/asm/mmu.h @@ -240,6 +240,7 @@ static __always_inline bool mmu_has_feature(unsigned long feature) int i; BUILD_BUG_ON(!__builtin_constant_p(feature)); + BUILD_BUG_ON(__builtin_popcountl(feature) > 1); #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG if (!static_key_feature_checks_initialized) {