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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2017-03-30 11:07:25 +0300
committerIngo Molnar <mingo@kernel.org>2017-04-04 08:22:33 +0200
commit3677d4c6a2010e4f5a0ca8b617b595fe4cc7ba6b (patch)
tree8a63227fdefdfd03eb122168ebb167566c9a156e /arch/x86/boot/cpuflags.c
parent7f75540ff2ca84dbac26cf9deeb620cbf5646f5e (diff)
downloadlinux-3677d4c6a2010e4f5a0ca8b617b595fe4cc7ba6b.tar.bz2
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: 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>
Diffstat (limited to 'arch/x86/boot/cpuflags.c')
-rw-r--r--arch/x86/boot/cpuflags.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c
index 6687ab953257..9e77c23c2422 100644
--- a/arch/x86/boot/cpuflags.c
+++ b/arch/x86/boot/cpuflags.c
@@ -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);