4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Andy Lutomirski <l...@kernel.org> commit cba4671af7550e008f7a7835f06df0763825bf3e upstream. 32-bit kernels on new hardware will see PCID in CPUID, but PCID can only be used in 64-bit mode. Rather than making all PCID code conditional, just disable the feature on 32-bit builds. Signed-off-by: Andy Lutomirski <l...@kernel.org> Reviewed-by: Nadav Amit <nadav.a...@gmail.com> Reviewed-by: Borislav Petkov <b...@suse.de> Reviewed-by: Thomas Gleixner <t...@linutronix.de> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Arjan van de Ven <ar...@linux.intel.com> Cc: Borislav Petkov <b...@alien8.de> Cc: Dave Hansen <dave.han...@intel.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Mel Gorman <mgor...@suse.de> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Rik van Riel <r...@redhat.com> Cc: linux...@kvack.org Link: http://lkml.kernel.org/r/2e391769192a4d31b808410c383c6bf0734bc6ea.1498751203.git.l...@kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> Cc: Hugh Dickins <hu...@google.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/x86/include/asm/disabled-features.h | 4 +++- arch/x86/kernel/cpu/bugs.c | 8 ++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -21,11 +21,13 @@ # define DISABLE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31)) # define DISABLE_CYRIX_ARR (1<<(X86_FEATURE_CYRIX_ARR & 31)) # define DISABLE_CENTAUR_MCR (1<<(X86_FEATURE_CENTAUR_MCR & 31)) +# define DISABLE_PCID 0 #else # define DISABLE_VME 0 # define DISABLE_K6_MTRR 0 # define DISABLE_CYRIX_ARR 0 # define DISABLE_CENTAUR_MCR 0 +# define DISABLE_PCID (1<<(X86_FEATURE_PCID & 31)) #endif /* CONFIG_X86_64 */ #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS @@ -43,7 +45,7 @@ #define DISABLED_MASK1 0 #define DISABLED_MASK2 0 #define DISABLED_MASK3 (DISABLE_CYRIX_ARR|DISABLE_CENTAUR_MCR|DISABLE_K6_MTRR) -#define DISABLED_MASK4 0 +#define DISABLED_MASK4 (DISABLE_PCID) #define DISABLED_MASK5 0 #define DISABLED_MASK6 0 #define DISABLED_MASK7 0 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -19,6 +19,14 @@ void __init check_bugs(void) { +#ifdef CONFIG_X86_32 + /* + * Regardless of whether PCID is enumerated, the SDM says + * that it can't be enabled in 32-bit mode. + */ + setup_clear_cpu_cap(X86_FEATURE_PCID); +#endif + identify_boot_cpu(); #ifndef CONFIG_SMP pr_info("CPU: ");
