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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2009-03-16 17:24:34 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-03-16 18:36:31 -0700 |
| commit | 42854dc0a6320ff36722749acafa0697522d9556 (patch) | |
| tree | d85b34e78479e5b726cbe7f5632033dfc8b269a2 /arch/x86/include/asm/paravirt.h | |
| parent | 895791dac6946d535991edd11341046f8e85ea77 (diff) | |
| download | blackbird-op-linux-42854dc0a6320ff36722749acafa0697522d9556.tar.gz blackbird-op-linux-42854dc0a6320ff36722749acafa0697522d9556.zip | |
x86, paravirt: prevent gcc from generating the wrong addressing mode
Impact: fix crash on VMI (VMware)
When we generate a call sequence for calling a paravirtualized
function, we presume that the generated code is "call *0xXXXXX",
which is a 6 byte opcode; this is larger than a normal
direct call, and so we can patch a direct call over it.
At the moment, however we give gcc enough rope to hang us by
putting the address in a register and generating a two byte
indirect-via-register call. Prevent this by explicitly
dereferencing the function pointer and passing it into the
asm as a constant.
This prevents crashes in VMI, as it cannot handle unpatchable
callsites.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
LKML-Reference: <49BEEDC2.2070809@goop.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/paravirt.h')
| -rw-r--r-- | arch/x86/include/asm/paravirt.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index e299287e8e33..0c212d528c0a 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -360,7 +360,7 @@ extern struct pv_lock_ops pv_lock_ops; #define paravirt_type(op) \ [paravirt_typenum] "i" (PARAVIRT_PATCH(op)), \ - [paravirt_opptr] "m" (op) + [paravirt_opptr] "i" (&(op)) #define paravirt_clobber(clobber) \ [paravirt_clobber] "i" (clobber) @@ -412,7 +412,7 @@ int paravirt_disable_iospace(void); * offset into the paravirt_patch_template structure, and can therefore be * freely converted back into a structure offset. */ -#define PARAVIRT_CALL "call *%[paravirt_opptr];" +#define PARAVIRT_CALL "call *%c[paravirt_opptr];" /* * These macros are intended to wrap calls through one of the paravirt |
