riscv64: add syscall helpers

Use syscall helpers to optimized io_uring_enter(2) calls, eliminating
the need for libc functions. These wrappers are adapted from liburing.

Signed-off-by: michalbiesek <michalbiesek@gmail.com>

diff --git a/arch/arch-riscv64.h b/arch/arch-riscv64.h
index a74b7d475808256cb25c9472c85c1bc714eb98e0..9b8fd001d7af9d8d2094059ce9e478aaef5647f1 100644 (file)
--- a/arch/arch-riscv64.h
+++ b/arch/arch-riscv64.h
@@ -29,4 +29,90 @@ static inline int arch_init(char *envp[])
        return 0;
 }
 
+#define __do_syscallM(...) ({                                          \
+       __asm__ volatile (                                              \
+               "ecall"                                                 \
+               : "=r"(a0)                                              \
+               : __VA_ARGS__                                           \
+               : "memory", "a1");                                      \
+       (long) a0;                                                      \
+})
+
+#define __do_syscallN(...) ({                                          \
+       __asm__ volatile (                                              \
+               "ecall"                                                 \
+               : "=r"(a0)                                              \
+               : __VA_ARGS__                                           \
+               : "memory");                                    \
+       (long) a0;                                                      \
+})
+
+#define __do_syscall0(__n) ({                                          \
+       register long a7 __asm__("a7") = __n;                           \
+       register long a0 __asm__("a0");                                 \
+                                                                       \
+       __do_syscallM("r" (a7));                                        \
+})
+
+#define __do_syscall1(__n, __a) ({                                     \
+       register long a7 __asm__("a7") = __n;                           \
+       register __typeof__(__a) a0 __asm__("a0") = __a;                \
+                                                                       \
+       __do_syscallM("r" (a7), "0" (a0));                              \
+})
+
+#define __do_syscall2(__n, __a, __b) ({                                        \
+       register long a7 __asm__("a7") = __n;                           \
+       register __typeof__(__a) a0 __asm__("a0") = __a;                \
+       register __typeof__(__b) a1 __asm__("a1") = __b;                \
+                                                                       \
+       __do_syscallN("r" (a7), "0" (a0), "r" (a1));                    \
+})
+
+#define __do_syscall3(__n, __a, __b, __c) ({                           \
+       register long a7 __asm__("a7") = __n;                           \
+       register __typeof__(__a) a0 __asm__("a0") = __a;                \
+       register __typeof__(__b) a1 __asm__("a1") = __b;                \
+       register __typeof__(__c) a2 __asm__("a2") = __c;                \
+                                                                       \
+       __do_syscallN("r" (a7), "0" (a0), "r" (a1), "r" (a2));          \
+})
+
+#define __do_syscall4(__n, __a, __b, __c, __d) ({                      \
+       register long a7 __asm__("a7") = __n;                           \
+       register __typeof__(__a) a0 __asm__("a0") = __a;                \
+       register __typeof__(__b) a1 __asm__("a1") = __b;                \
+       register __typeof__(__c) a2 __asm__("a2") = __c;                \
+       register __typeof__(__d) a3 __asm__("a3") = __d;                \
+                                                                       \
+       __do_syscallN("r" (a7), "0" (a0), "r" (a1), "r" (a2), "r" (a3));\
+})
+
+#define __do_syscall5(__n, __a, __b, __c, __d, __e) ({                 \
+       register long a7 __asm__("a7") = __n;                           \
+       register __typeof__(__a) a0 __asm__("a0") = __a;                \
+       register __typeof__(__b) a1 __asm__("a1") = __b;                \
+       register __typeof__(__c) a2 __asm__("a2") = __c;                \
+       register __typeof__(__d) a3 __asm__("a3") = __d;                \
+       register __typeof__(__e) a4 __asm__("a4") = __e;                \
+                                                                       \
+       __do_syscallN("r" (a7), "0" (a0), "r" (a1), "r" (a2), "r" (a3), \
+                       "r"(a4));                                       \
+})
+
+#define __do_syscall6(__n, __a, __b, __c, __d, __e, __f) ({            \
+       register long a7 __asm__("a7") = __n;                           \
+       register __typeof__(__a) a0 __asm__("a0") = __a;                \
+       register __typeof__(__b) a1 __asm__("a1") = __b;                \
+       register __typeof__(__c) a2 __asm__("a2") = __c;                \
+       register __typeof__(__d) a3 __asm__("a3") = __d;                \
+       register __typeof__(__e) a4 __asm__("a4") = __e;                \
+       register __typeof__(__f) a5 __asm__("a5") = __f;                \
+                                                                       \
+       __do_syscallN("r" (a7), "0" (a0), "r" (a1), "r" (a2), "r" (a3), \
+                       "r" (a4), "r"(a5));                             \
+})
+
+#define FIO_ARCH_HAS_SYSCALL
+
 #endif