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Commit 3677d4c6 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
Browse files

x86/boot: Detect 5-level paging support 



In this initial implementation we force-require 5-level paging support
from the hardware, when compiled with CONFIG_X86_5LEVEL=y. (The kernel
will panic during boot on CPUs that don't support 5-level paging.)

We will implement boot-time switch between 4- and 5-level paging later.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170330080731.65421-2-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7f75540f

arch/x86/boot/cpucheck.c

+9 −0
Original line number Diff line number Diff line
@@ -44,6 +44,15 @@ static const u32 req_flags[NCAPINTS] = 
	0, /* REQUIRED_MASK5 not implemented in this file */

	REQUIRED_MASK6,

	0, /* REQUIRED_MASK7 not implemented in this file */

	0, /* REQUIRED_MASK8 not implemented in this file */

	0, /* REQUIRED_MASK9 not implemented in this file */

	0, /* REQUIRED_MASK10 not implemented in this file */

	0, /* REQUIRED_MASK11 not implemented in this file */

	0, /* REQUIRED_MASK12 not implemented in this file */

	0, /* REQUIRED_MASK13 not implemented in this file */

	0, /* REQUIRED_MASK14 not implemented in this file */

	0, /* REQUIRED_MASK15 not implemented in this file */

	REQUIRED_MASK16,

};



#define A32(a, b, c, d) (((d) << 24)+((c) << 16)+((b) << 8)+(a))

arch/x86/boot/cpuflags.c

+10 −2
Original line number Diff line number Diff line
@@ -70,16 +70,19 @@ int has_eflag(unsigned long mask) 
# define EBX_REG "=b"

#endif



static inline void cpuid(u32 id, u32 *a, u32 *b, u32 *c, u32 *d)

static inline void cpuid_count(u32 id, u32 count,

		u32 *a, u32 *b, u32 *c, u32 *d)

{

	asm volatile(".ifnc %%ebx,%3 ; movl  %%ebx,%3 ; .endif	\n\t"

		     "cpuid					\n\t"

		     ".ifnc %%ebx,%3 ; xchgl %%ebx,%3 ; .endif	\n\t"

		    : "=a" (*a), "=c" (*c), "=d" (*d), EBX_REG (*b)

		    : "a" (id)

		    : "a" (id), "c" (count)

	);

}



#define cpuid(id, a, b, c, d) cpuid_count(id, 0, a, b, c, d)



void get_cpuflags(void)

{

	u32 max_intel_level, max_amd_level;
@@ -108,6 +111,11 @@ void get_cpuflags(void) 
				cpu.model += ((tfms >> 16) & 0xf) << 4;

		}



		if (max_intel_level >= 0x00000007) {

			cpuid_count(0x00000007, 0, &ignored, &ignored,

					&cpu.flags[16], &ignored);

		}



		cpuid(0x80000000, &max_amd_level, &ignored, &ignored,

		      &ignored);

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

+7 −1
Original line number Diff line number Diff line
@@ -36,6 +36,12 @@ 
# define DISABLE_OSPKE		(1<<(X86_FEATURE_OSPKE & 31))

#endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */



#ifdef CONFIG_X86_5LEVEL

# define DISABLE_LA57	0

#else

# define DISABLE_LA57	(1<<(X86_FEATURE_LA57 & 31))

#endif



/*

 * Make sure to add features to the correct mask

 */
@@ -55,7 +61,7 @@ 
#define DISABLED_MASK13	0

#define DISABLED_MASK14	0

#define DISABLED_MASK15	0

#define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE)

#define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57)

#define DISABLED_MASK17	0

#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)

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

+7 −1
Original line number Diff line number Diff line
@@ -53,6 +53,12 @@ 
# define NEED_MOVBE	0

#endif



#ifdef CONFIG_X86_5LEVEL

# define NEED_LA57	(1<<(X86_FEATURE_LA57 & 31))

#else

# define NEED_LA57	0

#endif



#ifdef CONFIG_X86_64

#ifdef CONFIG_PARAVIRT

/* Paravirtualized systems may not have PSE or PGE available */
@@ -98,7 +104,7 @@ 
#define REQUIRED_MASK13	0

#define REQUIRED_MASK14	0

#define REQUIRED_MASK15	0

#define REQUIRED_MASK16	0

#define REQUIRED_MASK16	(NEED_LA57)

#define REQUIRED_MASK17	0

#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)