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| author | H.J. Lu <hjl.tools@gmail.com> | 2015-07-09 09:30:09 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2015-07-09 09:30:20 -0700 |
| commit | 2eb9ef29b698bb7706833236b4b9041f0c23ceef (patch) | |
| tree | dcd7f9da582252e2e77abfcae48079047d59a0c5 /sysdeps/x86_64/dl-trampoline.S | |
| parent | 14c5cbabc2d11004ab223ae5eae761ddf83ef99e (diff) | |
| download | glibc-2eb9ef29b698bb7706833236b4b9041f0c23ceef.tar.gz | |
Improve bndmov encoding with zero displacement
If x86-64 assembler doesn't support MPX, we encode bndmov instruction by
hand. When displacement is zero, assembler generates shorter encoding.
This patch improves bndmov encoding with zero displacement so that ld.so
is identical when using assemblers with and without MPX support.
* sysdeps/x86_64/dl-trampoline.S (_dl_runtime_resolve): Improve
bndmov encoding with zero displacement.
Diffstat (limited to 'sysdeps/x86_64/dl-trampoline.S')
| -rw-r--r-- | sysdeps/x86_64/dl-trampoline.S | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/sysdeps/x86_64/dl-trampoline.S b/sysdeps/x86_64/dl-trampoline.S index b151d3566d..678c57fc24 100644 --- a/sysdeps/x86_64/dl-trampoline.S +++ b/sysdeps/x86_64/dl-trampoline.S @@ -80,7 +80,11 @@ _dl_runtime_resolve: bndmov %bnd2, REGISTER_SAVE_BND2(%rsp) bndmov %bnd3, REGISTER_SAVE_BND3(%rsp) # else +# if REGISTER_SAVE_BND0 == 0 + .byte 0x66,0x0f,0x1b,0x04,0x24 +# else .byte 0x66,0x0f,0x1b,0x44,0x24,REGISTER_SAVE_BND0 +# endif .byte 0x66,0x0f,0x1b,0x4c,0x24,REGISTER_SAVE_BND1 .byte 0x66,0x0f,0x1b,0x54,0x24,REGISTER_SAVE_BND2 .byte 0x66,0x0f,0x1b,0x5c,0x24,REGISTER_SAVE_BND3 @@ -104,7 +108,11 @@ _dl_runtime_resolve: .byte 0x66,0x0f,0x1a,0x5c,0x24,REGISTER_SAVE_BND3 .byte 0x66,0x0f,0x1a,0x54,0x24,REGISTER_SAVE_BND2 .byte 0x66,0x0f,0x1a,0x4c,0x24,REGISTER_SAVE_BND1 +# if REGISTER_SAVE_BND0 == 0 + .byte 0x66,0x0f,0x1a,0x04,0x24 +# else .byte 0x66,0x0f,0x1a,0x44,0x24,REGISTER_SAVE_BND0 +# endif # endif #endif # Get register content back. |