Release 4.14 arch/x86/boot/cpuflags.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include "bitops.h"
#include <asm/processor-flags.h>
#include <asm/required-features.h>
#include <asm/msr-index.h>
#include "cpuflags.h"
struct cpu_features cpu;
u32 cpu_vendor[3];
static bool loaded_flags;
static int has_fpu(void)
{
u16 fcw = -1, fsw = -1;
unsigned long cr0;
asm volatile("mov %%cr0,%0" : "=r" (cr0));
if (cr0 & (X86_CR0_EM|X86_CR0_TS)) {
cr0 &= ~(X86_CR0_EM|X86_CR0_TS);
asm volatile("mov %0,%%cr0" : : "r" (cr0));
}
asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
: "+m" (fsw), "+m" (fcw));
return fsw == 0 && (fcw & 0x103f) == 0x003f;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kees Cook | 66 | 100.00% | 1 | 100.00% |
| Total | 66 | 100.00% | 1 | 100.00% |
/*
* For building the 16-bit code we want to explicitly specify 32-bit
* push/pop operations, rather than just saying 'pushf' or 'popf' and
* letting the compiler choose. But this is also included from the
* compressed/ directory where it may be 64-bit code, and thus needs
* to be 'pushfq' or 'popfq' in that case.
*/
#ifdef __x86_64__
#define PUSHF "pushfq"
#define POPF "popfq"
#else
#define PUSHF "pushfl"
#define POPF "popfl"
#endif
int has_eflag(unsigned long mask)
{
unsigned long f0, f1;
asm volatile(PUSHF " \n\t"
PUSHF " \n\t"
"pop %0 \n\t"
"mov %0,%1 \n\t"
"xor %2,%1 \n\t"
"push %1 \n\t"
POPF " \n\t"
PUSHF " \n\t"
"pop %1 \n\t"
POPF
: "=&r" (f0), "=&r" (f1)
: "ri" (mask));
return !!((f0^f1) & mask);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kees Cook | 30 | 96.77% | 1 | 50.00% |
| David Woodhouse | 1 | 3.23% | 1 | 50.00% |
| Total | 31 | 100.00% | 2 | 100.00% |
/* Handle x86_32 PIC using ebx. */
#if defined(__i386__) && defined(__PIC__)
# define EBX_REG "=r"
#else
# define EBX_REG "=b"
#endif
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), "c" (count)
);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kees Cook | 27 | 84.38% | 1 | 50.00% |
| Kirill A. Shutemov | 5 | 15.62% | 1 | 50.00% |
| Total | 32 | 100.00% | 2 | 100.00% |
#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;
u32 tfms;
u32 ignored;
if (loaded_flags)
return;
loaded_flags = true;
if (has_fpu())
set_bit(X86_FEATURE_FPU, cpu.flags);
if (has_eflag(X86_EFLAGS_ID)) {
cpuid(0x0, &max_intel_level, &cpu_vendor[0], &cpu_vendor[2],
&cpu_vendor[1]);
if (max_intel_level >= 0x00000001 &&
max_intel_level <= 0x0000ffff) {
cpuid(0x1, &tfms, &ignored, &cpu.flags[4],
&cpu.flags[0]);
cpu.level = (tfms >> 8) & 15;
cpu.family = cpu.level;
cpu.model = (tfms >> 4) & 15;
if (cpu.level >= 6)
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);
if (max_amd_level >= 0x80000001 &&
max_amd_level <= 0x8000ffff) {
cpuid(0x80000001, &ignored, &ignored, &cpu.flags[6],
&cpu.flags[1]);
}
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kees Cook | 218 | 84.17% | 1 | 25.00% |
| Kirill A. Shutemov | 32 | 12.36% | 1 | 25.00% |
| Dave Hansen | 8 | 3.09% | 1 | 25.00% |
| H. Peter Anvin | 1 | 0.39% | 1 | 25.00% |
| Total | 259 | 100.00% | 4 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kees Cook | 397 | 82.02% | 1 | 16.67% |
| Kirill A. Shutemov | 52 | 10.74% | 1 | 16.67% |
| David Woodhouse | 25 | 5.17% | 1 | 16.67% |
| Dave Hansen | 8 | 1.65% | 1 | 16.67% |
| H. Peter Anvin | 1 | 0.21% | 1 | 16.67% |
| Greg Kroah-Hartman | 1 | 0.21% | 1 | 16.67% |
| Total | 484 | 100.00% | 6 | 100.00% |
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