x86-64: add system call definitions

Avoid a libc function call, just define our own syscall wrappers for
this architecture. Lifted from liburing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/arch/arch-x86_64.h b/arch/arch-x86_64.h
index 25850f90e7dca51f9f6f597c793948c2ccf24753..86ce1b7ed7dd0f56de77575bcbf2d2ba99e85901 100644 (file)
--- a/arch/arch-x86_64.h
+++ b/arch/arch-x86_64.h
@@ -68,4 +68,117 @@ static inline int arch_rand_seed(unsigned long *seed)
        return 0;
 }
 
+#define __do_syscall0(NUM) ({                  \
+       intptr_t rax;                           \
+                                               \
+       __asm__ volatile(                       \
+               "syscall"                       \
+               : "=a"(rax)     /* %rax */      \
+               : "a"(NUM)      /* %rax */      \
+               : "rcx", "r11", "memory"        \
+       );                                      \
+       rax;                                    \
+})
+
+#define __do_syscall1(NUM, ARG1) ({            \
+       intptr_t rax;                           \
+                                               \
+       __asm__ volatile(                       \
+               "syscall"                       \
+               : "=a"(rax)     /* %rax */      \
+               : "a"((NUM)),   /* %rax */      \
+                 "D"((ARG1))   /* %rdi */      \
+               : "rcx", "r11", "memory"        \
+       );                                      \
+       rax;                                    \
+})
+
+#define __do_syscall2(NUM, ARG1, ARG2) ({      \
+       intptr_t rax;                           \
+                                               \
+       __asm__ volatile(                       \
+               "syscall"                       \
+               : "=a"(rax)     /* %rax */      \
+               : "a"((NUM)),   /* %rax */      \
+                 "D"((ARG1)),  /* %rdi */      \
+                 "S"((ARG2))   /* %rsi */      \
+               : "rcx", "r11", "memory"        \
+       );                                      \
+       rax;                                    \
+})
+
+#define __do_syscall3(NUM, ARG1, ARG2, ARG3) ({        \
+       intptr_t rax;                           \
+                                               \
+       __asm__ volatile(                       \
+               "syscall"                       \
+               : "=a"(rax)     /* %rax */      \
+               : "a"((NUM)),   /* %rax */      \
+                 "D"((ARG1)),  /* %rdi */      \
+                 "S"((ARG2)),  /* %rsi */      \
+                 "d"((ARG3))   /* %rdx */      \
+               : "rcx", "r11", "memory"        \
+       );                                      \
+       rax;                                    \
+})
+
+#define __do_syscall4(NUM, ARG1, ARG2, ARG3, ARG4) ({                  \
+       intptr_t rax;                                                   \
+       register __typeof__(ARG4) __r10 __asm__("r10") = (ARG4);        \
+                                                                       \
+       __asm__ volatile(                                               \
+               "syscall"                                               \
+               : "=a"(rax)     /* %rax */                              \
+               : "a"((NUM)),   /* %rax */                              \
+                 "D"((ARG1)),  /* %rdi */                              \
+                 "S"((ARG2)),  /* %rsi */                              \
+                 "d"((ARG3)),  /* %rdx */                              \
+                 "r"(__r10)    /* %r10 */                              \
+               : "rcx", "r11", "memory"                                \
+       );                                                              \
+       rax;                                                            \
+})
+
+#define __do_syscall5(NUM, ARG1, ARG2, ARG3, ARG4, ARG5) ({            \
+       intptr_t rax;                                                   \
+       register __typeof__(ARG4) __r10 __asm__("r10") = (ARG4);        \
+       register __typeof__(ARG5) __r8 __asm__("r8") = (ARG5);          \
+                                                                       \
+       __asm__ volatile(                                               \
+               "syscall"                                               \
+               : "=a"(rax)     /* %rax */                              \
+               : "a"((NUM)),   /* %rax */                              \
+                 "D"((ARG1)),  /* %rdi */                              \
+                 "S"((ARG2)),  /* %rsi */                              \
+                 "d"((ARG3)),  /* %rdx */                              \
+                 "r"(__r10),   /* %r10 */                              \
+                 "r"(__r8)     /* %r8 */                               \
+               : "rcx", "r11", "memory"                                \
+       );                                                              \
+       rax;                                                            \
+})
+
+#define __do_syscall6(NUM, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6) ({      \
+       intptr_t rax;                                                   \
+       register __typeof__(ARG4) __r10 __asm__("r10") = (ARG4);        \
+       register __typeof__(ARG5) __r8 __asm__("r8") = (ARG5);          \
+       register __typeof__(ARG6) __r9 __asm__("r9") = (ARG6);          \
+                                                                       \
+       __asm__ volatile(                                               \
+               "syscall"                                               \
+               : "=a"(rax)     /* %rax */                              \
+               : "a"((NUM)),   /* %rax */                              \
+                 "D"((ARG1)),  /* %rdi */                              \
+                 "S"((ARG2)),  /* %rsi */                              \
+                 "d"((ARG3)),  /* %rdx */                              \
+                 "r"(__r10),   /* %r10 */                              \
+                 "r"(__r8),    /* %r8 */                               \
+                 "r"(__r9)     /* %r9 */                               \
+               : "rcx", "r11", "memory"                                \
+       );                                                              \
+       rax;                                                            \
+})
+
+#define FIO_ARCH_HAS_SYSCALL
+
 #endif