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/* SPDX-License-Identifier: MIT */
#ifndef __INTERNAL__LIBURING_SYSCALL_H
#error "This file should be included from src/syscall.h (liburing)"
#endif
#ifndef LIBURING_ARCH_X86_SYSCALL_H
#define LIBURING_ARCH_X86_SYSCALL_H
#if defined(__x86_64__)
/**
* Note for syscall registers usage (x86-64):
* - %rax is the syscall number.
* - %rax is also the return value.
* - %rdi is the 1st argument.
* - %rsi is the 2nd argument.
* - %rdx is the 3rd argument.
* - %r10 is the 4th argument (**yes it's %r10, not %rcx!**).
* - %r8 is the 5th argument.
* - %r9 is the 6th argument.
*
* `syscall` instruction will clobber %r11 and %rcx.
*
* After the syscall returns to userspace:
* - %r11 will contain %rflags.
* - %rcx will contain the return address.
*
* IOW, after the syscall returns to userspace:
* %r11 == %rflags and %rcx == %rip.
*/
static inline void *uring_mmap(void *addr, size_t length, int prot, int flags,
int fd, off_t offset)
{
void *rax;
register int r10 __asm__("r10") = flags;
register int r8 __asm__("r8") = fd;
register off_t r9 __asm__("r9") = offset;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_mmap), /* %rax */
"D"(addr), /* %rdi */
"S"(length), /* %rsi */
"d"(prot), /* %rdx */
"r"(r10), /* %r10 */
"r"(r8), /* %r8 */
"r"(r9) /* %r9 */
: "memory", "rcx", "r11"
);
return rax;
}
static inline int uring_munmap(void *addr, size_t length)
{
long rax;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_munmap), /* %rax */
"D"(addr), /* %rdi */
"S"(length) /* %rsi */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int uring_madvise(void *addr, size_t length, int advice)
{
long rax;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_madvise), /* %rax */
"D"(addr), /* %rdi */
"S"(length), /* %rsi */
"d"(advice) /* %rdx */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int uring_getrlimit(int resource, struct rlimit *rlim)
{
long rax;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_getrlimit), /* %rax */
"D"(resource), /* %rdi */
"S"(rlim) /* %rsi */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int uring_setrlimit(int resource, const struct rlimit *rlim)
{
long rax;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_setrlimit), /* %rax */
"D"(resource), /* %rdi */
"S"(rlim) /* %rsi */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int uring_close(int fd)
{
long rax;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_close), /* %rax */
"D"(fd) /* %rdi */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int ____sys_io_uring_register(int fd, unsigned opcode,
const void *arg,
unsigned nr_args)
{
long rax;
register unsigned r10 __asm__("r10") = nr_args;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_io_uring_register), /* %rax */
"D"(fd), /* %rdi */
"S"(opcode), /* %rsi */
"d"(arg), /* %rdx */
"r"(r10) /* %r10 */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int ____sys_io_uring_setup(unsigned entries,
struct io_uring_params *p)
{
long rax;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_io_uring_setup), /* %rax */
"D"(entries), /* %rdi */
"S"(p) /* %rsi */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int ____sys_io_uring_enter2(int fd, unsigned to_submit,
unsigned min_complete, unsigned flags,
sigset_t *sig, int sz)
{
long rax;
register unsigned r10 __asm__("r10") = flags;
register sigset_t *r8 __asm__("r8") = sig;
register int r9 __asm__("r9") = sz;
__asm__ volatile(
"syscall"
: "=a"(rax) /* %rax */
: "a"(__NR_io_uring_enter), /* %rax */
"D"(fd), /* %rdi */
"S"(to_submit), /* %rsi */
"d"(min_complete), /* %rdx */
"r"(r10), /* %r10 */
"r"(r8), /* %r8 */
"r"(r9) /* %r9 */
: "memory", "rcx", "r11"
);
return (int) rax;
}
static inline int ____sys_io_uring_enter(int fd, unsigned to_submit,
unsigned min_complete, unsigned flags,
sigset_t *sig)
{
return ____sys_io_uring_enter2(fd, to_submit, min_complete, flags, sig,
_NSIG / 8);
}
#else /* #if defined(__x86_64__) */
/*
* For x86 (32-bit), fallback to libc wrapper.
* We can't use CONFIG_NOLIBC for x86 (32-bit) at the moment.
*
* TODO: Add x86 (32-bit) nolibc support.
*/
#ifdef CONFIG_NOLIBC
#error "x86 (32-bit) is currently not supported for nolibc builds"
#endif
#include "../generic/syscall.h"
#endif /* #if defined(__x86_64__) */
#endif /* #ifndef LIBURING_ARCH_X86_SYSCALL_H */
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