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| author | Richard W.M. Jones <rjones@redhat.com> | 2012-03-17 10:32:39 +0000 |
|---|---|---|
| committer | Richard W.M. Jones <rjones@redhat.com> | 2012-03-17 10:53:56 +0000 |
| commit | 53cf9493343e34b09622a544c84957d60d50c038 (patch) | |
| tree | be4c3d3ea979e08f998c586b9644154e477ce871 | |
| parent | d87e9cbae34b22c89e6094263ae44567f5b5bd90 (diff) | |
| download | virt-what-53cf9493343e34b09622a544c84957d60d50c038.tar.gz virt-what-53cf9493343e34b09622a544c84957d60d50c038.tar.xz virt-what-53cf9493343e34b09622a544c84957d60d50c038.zip | |
Preserve %ebx across CPUID when using PIE (thanks Faustus, Anthony Basile from Gentoo).
PIE on i686 uses %ebx as a base register. Don't clobber it across the
CPUID instruction.
https://bugs.gentoo.org/show_bug.cgi?id=341271
https://bugzilla.redhat.com/show_bug.cgi?id=804282
| -rw-r--r-- | virt-what-cpuid-helper.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/virt-what-cpuid-helper.c b/virt-what-cpuid-helper.c index 8b81be3..7812545 100644 --- a/virt-what-cpuid-helper.c +++ b/virt-what-cpuid-helper.c @@ -31,8 +31,8 @@ cpuid (unsigned int eax, char *sig) unsigned int *sig32 = (unsigned int *) sig; asm volatile ( - "xor %%ebx, %%ebx; cpuid" - : "=a" (eax), "=b" (sig32[0]), "=c" (sig32[1]), "=d" (sig32[2]) + "xchgl %%ebx,%1; xor %%ebx,%%ebx; cpuid; xchgl %%ebx,%1" + : "=a" (eax), "+r" (sig32[0]), "=c" (sig32[1]), "=d" (sig32[2]) : "0" (eax)); sig[12] = 0; |