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x86/boot: Detect 5-level paging support

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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: Kirill 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kirill A. Shutemov 2017-03-30 11:07:25 +03:00 committed by Ingo Molnar
parent 7f75540ff2
commit 3677d4c6a2
4 changed files with 33 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
arch/x86/boot/cpucheck.c
View File

@ -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))

12
arch/x86/boot/cpuflags.c
View File

@ -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);

8
arch/x86/include/asm/disabled-features.h
View File

@ -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)

8
arch/x86/include/asm/required-features.h
View File

@ -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)