Commit-ID: 42854dc0a6320ff36722749acafa0697522d9556 Gitweb: http://git.kernel.org/tip/42854dc0a6320ff36722749acafa0697522d9556 Author: Jeremy Fitzhardinge <jeremy@xxxxxxxx> AuthorDate: Mon, 16 Mar 2009 17:24:34 -0700 Commit: H. Peter Anvin <hpa@xxxxxxxxx> CommitDate: Mon, 16 Mar 2009 18:36:31 -0700 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@xxxxxxxxxx> Cc: Alok Kataria <akataria@xxxxxxxxxx> LKML-Reference: <49BEEDC2.2070809@xxxxxxxx> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx> --- 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 e299287..0c212d5 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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