| From cba4671af7550e008f7a7835f06df0763825bf3e Mon Sep 17 00:00:00 2001 |
| From: Andy Lutomirski <luto@kernel.org> |
| Date: Thu, 29 Jun 2017 08:53:19 -0700 |
| Subject: x86/mm: Disable PCID on 32-bit kernels |
| |
| From: Andy Lutomirski <luto@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 <luto@kernel.org> |
| Reviewed-by: Nadav Amit <nadav.amit@gmail.com> |
| Reviewed-by: Borislav Petkov <bp@suse.de> |
| Reviewed-by: Thomas Gleixner <tglx@linutronix.de> |
| Cc: Andrew Morton <akpm@linux-foundation.org> |
| Cc: Arjan van de Ven <arjan@linux.intel.com> |
| Cc: Borislav Petkov <bp@alien8.de> |
| Cc: Dave Hansen <dave.hansen@intel.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Mel Gorman <mgorman@suse.de> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Rik van Riel <riel@redhat.com> |
| Cc: linux-mm@kvack.org |
| Link: http://lkml.kernel.org/r/2e391769192a4d31b808410c383c6bf0734bc6ea.1498751203.git.luto@kernel.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Cc: Hugh Dickins <hughd@google.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@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: "); |