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x86/paravirt: implement PVOP_CALL macros for callee-save functions
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Impact: Optimization

Functions with the callee save calling convention clobber many fewer
registers than the normal C calling convention.  Implement variants of
PVOP_V?CALL* accordingly.  This only bothers with functions up to 3
args, since functions with more args may as well use the normal
calling convention.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Jeremy Fitzhardinge authored and H. Peter Anvin committed Jan 30, 2009
1 parent ecb93d1 commit 791bad9
Showing 1 changed file with 99 additions and 35 deletions.
134 changes: 99 additions & 35 deletions arch/x86/include/asm/paravirt.h
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Original file line number Diff line number Diff line change
Expand Up @@ -510,121 +510,185 @@ int paravirt_disable_iospace(void);
* makes sure the incoming and outgoing types are always correct.
*/
#ifdef CONFIG_X86_32
#define PVOP_VCALL_ARGS unsigned long __eax, __edx, __ecx
#define PVOP_VCALL_ARGS \
unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx
#define PVOP_CALL_ARGS PVOP_VCALL_ARGS

#define PVOP_CALL_ARG1(x) "a" ((unsigned long)(x))
#define PVOP_CALL_ARG2(x) "d" ((unsigned long)(x))
#define PVOP_CALL_ARG3(x) "c" ((unsigned long)(x))

#define PVOP_VCALL_CLOBBERS "=a" (__eax), "=d" (__edx), \
"=c" (__ecx)
#define PVOP_CALL_CLOBBERS PVOP_VCALL_CLOBBERS

#define PVOP_VCALLEE_CLOBBERS "=a" (__eax)
#define PVOP_CALLEE_CLOBBERS PVOP_VCALLEE_CLOBBERS

#define EXTRA_CLOBBERS
#define VEXTRA_CLOBBERS
#else
#define PVOP_VCALL_ARGS unsigned long __edi, __esi, __edx, __ecx
#else /* CONFIG_X86_64 */
#define PVOP_VCALL_ARGS \
unsigned long __edi = __edi, __esi = __esi, \
__edx = __edx, __ecx = __ecx
#define PVOP_CALL_ARGS PVOP_VCALL_ARGS, __eax

#define PVOP_CALL_ARG1(x) "D" ((unsigned long)(x))
#define PVOP_CALL_ARG2(x) "S" ((unsigned long)(x))
#define PVOP_CALL_ARG3(x) "d" ((unsigned long)(x))
#define PVOP_CALL_ARG4(x) "c" ((unsigned long)(x))

#define PVOP_VCALL_CLOBBERS "=D" (__edi), \
"=S" (__esi), "=d" (__edx), \
"=c" (__ecx)

#define PVOP_CALL_CLOBBERS PVOP_VCALL_CLOBBERS, "=a" (__eax)

#define PVOP_VCALLEE_CLOBBERS "=a" (__eax)
#define PVOP_CALLEE_CLOBBERS PVOP_VCALLEE_CLOBBERS

#define EXTRA_CLOBBERS , "r8", "r9", "r10", "r11"
#define VEXTRA_CLOBBERS , "rax", "r8", "r9", "r10", "r11"
#endif
#endif /* CONFIG_X86_32 */

#ifdef CONFIG_PARAVIRT_DEBUG
#define PVOP_TEST_NULL(op) BUG_ON(op == NULL)
#else
#define PVOP_TEST_NULL(op) ((void)op)
#endif

#define __PVOP_CALL(rettype, op, pre, post, ...) \
#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, \
pre, post, ...) \
({ \
rettype __ret; \
PVOP_CALL_ARGS; \
PVOP_CALL_ARGS; \
PVOP_TEST_NULL(op); \
/* This is 32-bit specific, but is okay in 64-bit */ \
/* since this condition will never hold */ \
if (sizeof(rettype) > sizeof(unsigned long)) { \
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
: PVOP_CALL_CLOBBERS \
: call_clbr \
: paravirt_type(op), \
paravirt_clobber(CLBR_ANY), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
: "memory", "cc" EXTRA_CLOBBERS); \
: "memory", "cc" extra_clbr); \
__ret = (rettype)((((u64)__edx) << 32) | __eax); \
} else { \
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
: PVOP_CALL_CLOBBERS \
: call_clbr \
: paravirt_type(op), \
paravirt_clobber(CLBR_ANY), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
: "memory", "cc" EXTRA_CLOBBERS); \
: "memory", "cc" extra_clbr); \
__ret = (rettype)__eax; \
} \
__ret; \
})
#define __PVOP_VCALL(op, pre, post, ...) \

#define __PVOP_CALL(rettype, op, pre, post, ...) \
____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS, \
EXTRA_CLOBBERS, pre, post, ##__VA_ARGS__)

#define __PVOP_CALLEESAVE(rettype, op, pre, post, ...) \
____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
PVOP_CALLEE_CLOBBERS, , \
pre, post, ##__VA_ARGS__)


#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, pre, post, ...) \
({ \
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
: PVOP_VCALL_CLOBBERS \
: call_clbr \
: paravirt_type(op), \
paravirt_clobber(CLBR_ANY), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
: "memory", "cc" VEXTRA_CLOBBERS); \
: "memory", "cc" extra_clbr); \
})

#define __PVOP_VCALL(op, pre, post, ...) \
____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
VEXTRA_CLOBBERS, \
pre, post, ##__VA_ARGS__)

#define __PVOP_VCALLEESAVE(rettype, op, pre, post, ...) \
____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
PVOP_VCALLEE_CLOBBERS, , \
pre, post, ##__VA_ARGS__)



#define PVOP_CALL0(rettype, op) \
__PVOP_CALL(rettype, op, "", "")
#define PVOP_VCALL0(op) \
__PVOP_VCALL(op, "", "")

#define PVOP_CALLEE0(rettype, op) \
__PVOP_CALLEESAVE(rettype, op, "", "")
#define PVOP_VCALLEE0(op) \
__PVOP_VCALLEESAVE(op, "", "")


#define PVOP_CALL1(rettype, op, arg1) \
__PVOP_CALL(rettype, op, "", "", "0" ((unsigned long)(arg1)))
__PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
#define PVOP_VCALL1(op, arg1) \
__PVOP_VCALL(op, "", "", "0" ((unsigned long)(arg1)))
__PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1))

#define PVOP_CALLEE1(rettype, op, arg1) \
__PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
#define PVOP_VCALLEE1(op, arg1) \
__PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1))


#define PVOP_CALL2(rettype, op, arg1, arg2) \
__PVOP_CALL(rettype, op, "", "", "0" ((unsigned long)(arg1)), \
"1" ((unsigned long)(arg2)))
__PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))
#define PVOP_VCALL2(op, arg1, arg2) \
__PVOP_VCALL(op, "", "", "0" ((unsigned long)(arg1)), \
"1" ((unsigned long)(arg2)))
__PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))

#define PVOP_CALLEE2(rettype, op, arg1, arg2) \
__PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))
#define PVOP_VCALLEE2(op, arg1, arg2) \
__PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))


#define PVOP_CALL3(rettype, op, arg1, arg2, arg3) \
__PVOP_CALL(rettype, op, "", "", "0" ((unsigned long)(arg1)), \
"1"((unsigned long)(arg2)), "2"((unsigned long)(arg3)))
__PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))
#define PVOP_VCALL3(op, arg1, arg2, arg3) \
__PVOP_VCALL(op, "", "", "0" ((unsigned long)(arg1)), \
"1"((unsigned long)(arg2)), "2"((unsigned long)(arg3)))
__PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))

/* This is the only difference in x86_64. We can make it much simpler */
#ifdef CONFIG_X86_32
#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
__PVOP_CALL(rettype, op, \
"push %[_arg4];", "lea 4(%%esp),%%esp;", \
"0" ((u32)(arg1)), "1" ((u32)(arg2)), \
"2" ((u32)(arg3)), [_arg4] "mr" ((u32)(arg4)))
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), [_arg4] "mr" ((u32)(arg4)))
#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
__PVOP_VCALL(op, \
"push %[_arg4];", "lea 4(%%esp),%%esp;", \
"0" ((u32)(arg1)), "1" ((u32)(arg2)), \
"2" ((u32)(arg3)), [_arg4] "mr" ((u32)(arg4)))
#else
#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
__PVOP_CALL(rettype, op, "", "", "0" ((unsigned long)(arg1)), \
"1"((unsigned long)(arg2)), "2"((unsigned long)(arg3)), \
"3"((unsigned long)(arg4)))
__PVOP_CALL(rettype, op, "", "", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
__PVOP_VCALL(op, "", "", "0" ((unsigned long)(arg1)), \
"1"((unsigned long)(arg2)), "2"((unsigned long)(arg3)), \
"3"((unsigned long)(arg4)))
__PVOP_VCALL(op, "", "", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
#endif

static inline int paravirt_enabled(void)
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