diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/include/asm/paravirt_types.h | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 89df6c6617f5..f3d601574730 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -294,6 +294,7 @@ extern struct paravirt_patch_template pv_ops; " .byte " type "\n" \ " .byte 772b-771b\n" \ " .short " clobber "\n" \ + _ASM_ALIGN "\n" \ ".popsection\n" /* Generate patchable code, with the default asm parameters. */ @@ -328,7 +329,7 @@ int paravirt_disable_iospace(void); * Unfortunately, this is a relatively slow operation for modern CPUs, * because it cannot necessarily determine what the destination * address is. In this case, the address is a runtime constant, so at - * the very least we can patch the call to e a simple direct call, or + * the very least we can patch the call to a simple direct call, or, * ideally, patch an inline implementation into the callsite. (Direct * calls are essentially free, because the call and return addresses * are completely predictable.) @@ -339,10 +340,10 @@ int paravirt_disable_iospace(void); * on the stack. All caller-save registers (eax,edx,ecx) are expected * to be modified (either clobbered or used for return values). * X86_64, on the other hand, already specifies a register-based calling - * conventions, returning at %rax, with parameters going on %rdi, %rsi, + * conventions, returning at %rax, with parameters going in %rdi, %rsi, * %rdx, and %rcx. Note that for this reason, x86_64 does not need any * special handling for dealing with 4 arguments, unlike i386. - * However, x86_64 also have to clobber all caller saved registers, which + * However, x86_64 also has to clobber all caller saved registers, which * unfortunately, are quite a bit (r8 - r11) * * The call instruction itself is marked by placing its start address @@ -360,22 +361,22 @@ int paravirt_disable_iospace(void); * There are 5 sets of PVOP_* macros for dealing with 0-4 arguments. * It could be extended to more arguments, but there would be little * to be gained from that. For each number of arguments, there are - * the two VCALL and CALL variants for void and non-void functions. + * two VCALL and CALL variants for void and non-void functions. * * When there is a return value, the invoker of the macro must specify * the return type. The macro then uses sizeof() on that type to - * determine whether its a 32 or 64 bit value, and places the return + * determine whether it's a 32 or 64 bit value and places the return * in the right register(s) (just %eax for 32-bit, and %edx:%eax for - * 64-bit). For x86_64 machines, it just returns at %rax regardless of + * 64-bit). For x86_64 machines, it just returns in %rax regardless of * the return value size. * - * 64-bit arguments are passed as a pair of adjacent 32-bit arguments + * 64-bit arguments are passed as a pair of adjacent 32-bit arguments; * i386 also passes 64-bit arguments as a pair of adjacent 32-bit arguments * in low,high order * * Small structures are passed and returned in registers. The macro * calling convention can't directly deal with this, so the wrapper - * functions must do this. + * functions must do it. * * These PVOP_* macros are only defined within this header. This * means that all uses must be wrapped in inline functions. This also @@ -414,8 +415,17 @@ int paravirt_disable_iospace(void); "=c" (__ecx) #define PVOP_CALL_CLOBBERS PVOP_VCALL_CLOBBERS, "=a" (__eax) -/* void functions are still allowed [re]ax for scratch */ +/* + * void functions are still allowed [re]ax for scratch. + * + * The ZERO_CALL_USED REGS feature may end up zeroing out callee-saved + * registers. Make sure we model this with the appropriate clobbers. + */ +#ifdef CONFIG_ZERO_CALL_USED_REGS +#define PVOP_VCALLEE_CLOBBERS "=a" (__eax), PVOP_VCALL_CLOBBERS +#else #define PVOP_VCALLEE_CLOBBERS "=a" (__eax) +#endif #define PVOP_CALLEE_CLOBBERS PVOP_VCALLEE_CLOBBERS #define EXTRA_CLOBBERS , "r8", "r9", "r10", "r11" |