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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Macros for issuing an inline system call from the vDSO.
*/
#ifndef X86_ASM_VDSO_SYS_CALL_H
#define X86_ASM_VDSO_SYS_CALL_H
#include <linux/compiler.h>
#include <asm/cpufeatures.h>
#include <asm/alternative.h>
#ifdef CONFIG_X86_64
# define __sys_instr "syscall"
# define __sys_clobber "rcx", "r11", "memory"
# define __sys_nr(x,y) __NR_ ## x
# define __sys_reg1 "rdi"
# define __sys_reg2 "rsi"
# define __sys_reg3 "rdx"
# define __sys_reg4 "r10"
# define __sys_reg5 "r8"
#else
# define __sys_instr ALTERNATIVE("ds;ds;ds;int $0x80", \
"call __kernel_vsyscall", \
X86_FEATURE_SYSFAST32)
# define __sys_clobber "memory"
# define __sys_nr(x,y) __NR_ ## x ## y
# define __sys_reg1 "ebx"
# define __sys_reg2 "ecx"
# define __sys_reg3 "edx"
# define __sys_reg4 "esi"
# define __sys_reg5 "edi"
#endif
/*
* Example usage:
*
* result = VDSO_SYSCALL3(foo,64,x,y,z);
*
* ... calls foo(x,y,z) on 64 bits, and foo64(x,y,z) on 32 bits.
*
* VDSO_SYSCALL6() is currently missing, because it would require
* special handling for %ebp on 32 bits when the vdso is compiled with
* frame pointers enabled (the default on 32 bits.) Add it as a special
* case when and if it becomes necessary.
*/
#define _VDSO_SYSCALL(name,suf32,...) \
({ \
long _sys_num_ret = __sys_nr(name,suf32); \
asm_inline volatile( \
__sys_instr \
: "+a" (_sys_num_ret) \
: __VA_ARGS__ \
: __sys_clobber); \
_sys_num_ret; \
})
#define VDSO_SYSCALL0(name,suf32) \
_VDSO_SYSCALL(name,suf32)
#define VDSO_SYSCALL1(name,suf32,a1) \
({ \
register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
_VDSO_SYSCALL(name,suf32, \
"r" (_sys_arg1)); \
})
#define VDSO_SYSCALL2(name,suf32,a1,a2) \
({ \
register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
_VDSO_SYSCALL(name,suf32, \
"r" (_sys_arg1), "r" (_sys_arg2)); \
})
#define VDSO_SYSCALL3(name,suf32,a1,a2,a3) \
({ \
register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
register long _sys_arg3 asm(__sys_reg3) = (long)(a3); \
_VDSO_SYSCALL(name,suf32, \
"r" (_sys_arg1), "r" (_sys_arg2), \
"r" (_sys_arg3)); \
})
#define VDSO_SYSCALL4(name,suf32,a1,a2,a3,a4) \
({ \
register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
register long _sys_arg3 asm(__sys_reg3) = (long)(a3); \
register long _sys_arg4 asm(__sys_reg4) = (long)(a4); \
_VDSO_SYSCALL(name,suf32, \
"r" (_sys_arg1), "r" (_sys_arg2), \
"r" (_sys_arg3), "r" (_sys_arg4)); \
})
#define VDSO_SYSCALL5(name,suf32,a1,a2,a3,a4,a5) \
({ \
register long _sys_arg1 asm(__sys_reg1) = (long)(a1); \
register long _sys_arg2 asm(__sys_reg2) = (long)(a2); \
register long _sys_arg3 asm(__sys_reg3) = (long)(a3); \
register long _sys_arg4 asm(__sys_reg4) = (long)(a4); \
register long _sys_arg5 asm(__sys_reg5) = (long)(a5); \
_VDSO_SYSCALL(name,suf32, \
"r" (_sys_arg1), "r" (_sys_arg2), \
"r" (_sys_arg3), "r" (_sys_arg4), \
"r" (_sys_arg5)); \
})
#endif /* X86_VDSO_SYS_CALL_H */
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