diff options
Diffstat (limited to 'tools/misc/xen-detect.c')
| -rw-r--r-- | tools/misc/xen-detect.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/tools/misc/xen-detect.c b/tools/misc/xen-detect.c index 565f27adb4..787b5da90d 100644 --- a/tools/misc/xen-detect.c +++ b/tools/misc/xen-detect.c @@ -35,18 +35,21 @@ static void cpuid(uint32_t idx, uint32_t *regs, int pv_context) { - asm volatile ( #ifdef __i386__ -#define R(x) "%%e"#x"x" -#else -#define R(x) "%%r"#x"x" -#endif - "push "R(a)"; push "R(b)"; push "R(c)"; push "R(d)"\n\t" + /* Use the stack to avoid reg constraint failures with some gcc flags */ + asm volatile ( + "push %%eax; push %%ebx; push %%ecx; push %%edx\n\t" "test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t" "mov %%eax,(%2); mov %%ebx,4(%2)\n\t" "mov %%ecx,8(%2); mov %%edx,12(%2)\n\t" - "pop "R(d)"; pop "R(c)"; pop "R(b)"; pop "R(a)"\n\t" + "pop %%edx; pop %%ecx; pop %%ebx; pop %%eax\n\t" : : "a" (idx), "c" (pv_context), "S" (regs) : "memory" ); +#else + asm volatile ( + "test %5,%5 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t" + : "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3]) + : "0" (idx), "1" (pv_context), "2" (0) ); +#endif } static int check_for_xen(int pv_context) |