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Commit cba4671a authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/mm: Disable PCID on 32-bit kernels 



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: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarNadav Amit <nadav.amit@gmail.com>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarThomas 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: default avatarIngo Molnar <mingo@kernel.org>
parent 43858b4f

arch/x86/include/asm/disabled-features.h

+3 −1
Original line number Diff line number Diff line
@@ -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
@@ -49,7 +51,7 @@ 
#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

arch/x86/kernel/cpu/bugs.c

+8 −0
Original line number Diff line number Diff line
@@ -21,6 +21,14 @@ 


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();



	if (!IS_ENABLED(CONFIG_SMP)) {