linux/arch/x86/include/asm/linkage.h
Brian Gerst b12bdaf11f x86: use regparm(3) for passed-in pt_regs pointer
Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to take the pointer as an argument instead of relying on
the assumption that the pt_regs structure overlaps the function
arguments.

Drop the use of regparm(1) due to concern about gcc bugs, and to move
in the direction of the eventual removal of regparm(0) for asmlinkage.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-02-11 14:00:56 -08:00

121 lines
3.3 KiB
C

#ifndef _ASM_X86_LINKAGE_H
#define _ASM_X86_LINKAGE_H
#undef notrace
#define notrace __attribute__((no_instrument_function))
#ifdef CONFIG_X86_64
#define __ALIGN .p2align 4,,15
#define __ALIGN_STR ".p2align 4,,15"
#endif
#ifdef CONFIG_X86_32
#define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0)))
/*
* For 32-bit UML - mark functions implemented in assembly that use
* regparm input parameters:
*/
#define asmregparm __attribute__((regparm(3)))
/*
* Make sure the compiler doesn't do anything stupid with the
* arguments on the stack - they are owned by the *caller*, not
* the callee. This just fools gcc into not spilling into them,
* and keeps it from doing tailcall recursion and/or using the
* stack slots for temporaries, since they are live and "used"
* all the way to the end of the function.
*
* NOTE! On x86-64, all the arguments are in registers, so this
* only matters on a 32-bit kernel.
*/
#define asmlinkage_protect(n, ret, args...) \
__asmlinkage_protect##n(ret, ##args)
#define __asmlinkage_protect_n(ret, args...) \
__asm__ __volatile__ ("" : "=r" (ret) : "0" (ret), ##args)
#define __asmlinkage_protect0(ret) \
__asmlinkage_protect_n(ret)
#define __asmlinkage_protect1(ret, arg1) \
__asmlinkage_protect_n(ret, "g" (arg1))
#define __asmlinkage_protect2(ret, arg1, arg2) \
__asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2))
#define __asmlinkage_protect3(ret, arg1, arg2, arg3) \
__asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3))
#define __asmlinkage_protect4(ret, arg1, arg2, arg3, arg4) \
__asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \
"g" (arg4))
#define __asmlinkage_protect5(ret, arg1, arg2, arg3, arg4, arg5) \
__asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \
"g" (arg4), "g" (arg5))
#define __asmlinkage_protect6(ret, arg1, arg2, arg3, arg4, arg5, arg6) \
__asmlinkage_protect_n(ret, "g" (arg1), "g" (arg2), "g" (arg3), \
"g" (arg4), "g" (arg5), "g" (arg6))
#endif
#ifdef CONFIG_X86_ALIGNMENT_16
#define __ALIGN .align 16,0x90
#define __ALIGN_STR ".align 16,0x90"
#endif
/*
* to check ENTRY_X86/END_X86 and
* KPROBE_ENTRY_X86/KPROBE_END_X86
* unbalanced-missed-mixed appearance
*/
#define __set_entry_x86 .set ENTRY_X86_IN, 0
#define __unset_entry_x86 .set ENTRY_X86_IN, 1
#define __set_kprobe_x86 .set KPROBE_X86_IN, 0
#define __unset_kprobe_x86 .set KPROBE_X86_IN, 1
#define __macro_err_x86 .error "ENTRY_X86/KPROBE_X86 unbalanced,missed,mixed"
#define __check_entry_x86 \
.ifdef ENTRY_X86_IN; \
.ifeq ENTRY_X86_IN; \
__macro_err_x86; \
.abort; \
.endif; \
.endif
#define __check_kprobe_x86 \
.ifdef KPROBE_X86_IN; \
.ifeq KPROBE_X86_IN; \
__macro_err_x86; \
.abort; \
.endif; \
.endif
#define __check_entry_kprobe_x86 \
__check_entry_x86; \
__check_kprobe_x86
#define ENTRY_KPROBE_FINAL_X86 __check_entry_kprobe_x86
#define ENTRY_X86(name) \
__check_entry_kprobe_x86; \
__set_entry_x86; \
.globl name; \
__ALIGN; \
name:
#define END_X86(name) \
__unset_entry_x86; \
__check_entry_kprobe_x86; \
.size name, .-name
#define KPROBE_ENTRY_X86(name) \
__check_entry_kprobe_x86; \
__set_kprobe_x86; \
.pushsection .kprobes.text, "ax"; \
.globl name; \
__ALIGN; \
name:
#define KPROBE_END_X86(name) \
__unset_kprobe_x86; \
__check_entry_kprobe_x86; \
.size name, .-name; \
.popsection
#endif /* _ASM_X86_LINKAGE_H */