1) Initiate no libc support from x86-64 arch. 2) Create `src/arch` directory. This directory is used to save arch dependent files. 3) Add x86-64 syscalls and lib support. All of these are supposed to support build liburing without libc. Cc: Bedirhan KURT <windowz414@xxxxxxxxxxx> Cc: Louvian Lyndal <louvianlyndal@xxxxxxxxx> Link: https://github.com/axboe/liburing/issues/443 Signed-off-by: Ammar Faizi <ammar.faizi@xxxxxxxxxxxxxxxxxxxxx> --- src/arch/x86/lib.h | 26 ++++++ src/arch/x86/syscall.h | 200 +++++++++++++++++++++++++++++++++++++++++ src/lib.h | 8 ++ src/syscall.h | 71 +++++++++++---- 4 files changed, 290 insertions(+), 15 deletions(-) create mode 100644 src/arch/x86/lib.h create mode 100644 src/arch/x86/syscall.h diff --git a/src/arch/x86/lib.h b/src/arch/x86/lib.h new file mode 100644 index 0000000..0d4b321 --- /dev/null +++ b/src/arch/x86/lib.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: MIT */ + +#ifndef LIBURING_ARCH_X86_LIB_H +#define LIBURING_ARCH_X86_LIB_H + +#ifndef LIBURING_LIB_H +# error "This file should be included from src/lib.h (liburing)" +#endif + +#if defined(__x86_64__) + +static inline long __arch_impl_get_page_size(void) +{ + return 4096; +} + +#else /* #if defined(__x86_64__) */ + +/* + * TODO: Add x86 (32-bit) support here. + */ +#error "x86 (32-bit) is currently not supported" + +#endif /* #if defined(__x86_64__) */ + +#endif /* #ifndef LIBURING_ARCH_X86_LIB_H */ diff --git a/src/arch/x86/syscall.h b/src/arch/x86/syscall.h new file mode 100644 index 0000000..1f36310 --- /dev/null +++ b/src/arch/x86/syscall.h @@ -0,0 +1,200 @@ +/* SPDX-License-Identifier: MIT */ + +#ifndef LIBURING_ARCH_X86_SYSCALL_H +#define LIBURING_ARCH_X86_SYSCALL_H + +#ifndef LIBURING_SYSCALL_H +# error "This file should be included from src/syscall.h (liburing)" +#endif + +#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 *__arch_impl_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 int r9 __asm__("r9") = offset; + + __asm__ volatile( + "syscall" + : "=a"(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 __arch_impl_munmap(void *addr, size_t length) +{ + int eax; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_munmap), /* %rax */ + "D"(addr), /* %rdi */ + "S"(length) /* %rsi */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_madvise(void *addr, size_t length, int advice) +{ + int eax; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_madvise), /* %rax */ + "D"(addr), /* %rdi */ + "S"(length), /* %rsi */ + "d"(advice) /* %rdx */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_getrlimit(int resource, struct rlimit *rlim) +{ + int eax; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_getrlimit), /* %rax */ + "D"(resource), /* %rdi */ + "S"(rlim) /* %rsi */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_setrlimit(int resource, const struct rlimit *rlim) +{ + int eax; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_setrlimit), /* %rax */ + "D"(resource), /* %rdi */ + "S"(rlim) /* %rsi */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_close(int fd) +{ + int eax; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_close), /* %rax */ + "D"(fd) /* %rdi */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_io_uring_register(int fd, unsigned opcode, + const void *arg, + unsigned nr_args) +{ + int eax; + register unsigned r10 __asm__("r10") = nr_args; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_io_uring_register), /* %rax */ + "D"(fd), /* %rdi */ + "S"(opcode), /* %rsi */ + "d"(arg), /* %rdx */ + "r"(r10) /* %r10 */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_io_uring_setup(unsigned entries, + struct io_uring_params *p) +{ + int eax; + + __asm__ volatile( + "syscall" + : "=a"(eax) /* %rax */ + : "a"(__NR_io_uring_setup), /* %rax */ + "D"(entries), /* %rdi */ + "S"(p) /* %rsi */ + : "memory", "rcx", "r11" + ); + return eax; +} + +static inline int __arch_impl_io_uring_enter(int fd, unsigned to_submit, + unsigned min_complete, + unsigned flags, sigset_t *sig, + int sz) +{ + int eax; + register unsigned r10 __asm__("r10") = flags; + register sigset_t *r8 __asm__("r8") = sig; + register int r9 __asm__("r9") = sz; + + __asm__ volatile( + "syscall" + : "=a"(eax) + : "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 eax; +} + +#else /* #if defined(__x86_64__) */ + +/* + * TODO: Add x86 (32-bit) support here. + */ +#error "x86 (32-bit) is currently not supported" + +#endif /* #if defined(__x86_64__) */ + +#endif /* #ifndef LIBURING_ARCH_X86_SYSCALL_H */ diff --git a/src/lib.h b/src/lib.h index 171eee7..baacabe 100644 --- a/src/lib.h +++ b/src/lib.h @@ -6,6 +6,14 @@ #include <string.h> #include <unistd.h> +#ifdef LIBURING_NOLIBC +# if defined(__x86_64__) || defined(__i386__) +# include "arch/x86/lib.h" +# else +# error "The arch is currently not supported to build liburing without libc" +# endif +#endif + #ifndef offsetof # define offsetof(TYPE, FIELD) ((size_t) &((TYPE *)0)->FIELD) #endif diff --git a/src/syscall.h b/src/syscall.h index 9eff968..82f5db0 100644 --- a/src/syscall.h +++ b/src/syscall.h @@ -29,13 +29,13 @@ # endif #elif defined __mips__ # ifndef __NR_io_uring_setup -# define __NR_io_uring_setup (__NR_Linux + 425) +# define __NR_io_uring_setup (__NR_Linux + 425) # endif # ifndef __NR_io_uring_enter -# define __NR_io_uring_enter (__NR_Linux + 426) +# define __NR_io_uring_enter (__NR_Linux + 426) # endif # ifndef __NR_io_uring_register -# define __NR_io_uring_register (__NR_Linux + 427) +# define __NR_io_uring_register (__NR_Linux + 427) # endif #else /* !__alpha__ and !__mips__ */ # ifndef __NR_io_uring_setup @@ -49,9 +49,22 @@ # endif #endif - +/* + * Don't put this below the #include "arch/$arch/syscall.h", that + * file may need it. + */ struct io_uring_params; + +#ifdef LIBURING_NOLIBC +# if defined(__x86_64__) || defined(__i386__) +# include "arch/x86/syscall.h" +# else +# error "The arch is currently not supported to build liburing without libc" +# endif +#endif + + /* * System calls */ @@ -68,12 +81,12 @@ static inline void *ERR_PTR(intptr_t n) return (void *) n; } -static inline intptr_t PTR_ERR(void *ptr) +static inline intptr_t PTR_ERR(const void *ptr) { return (intptr_t) ptr; } -static inline bool IS_ERR(void *ptr) +static inline bool IS_ERR(const void *ptr) { return uring_unlikely((uintptr_t) ptr >= (uintptr_t) -4095UL); } @@ -81,30 +94,40 @@ static inline bool IS_ERR(void *ptr) static inline int ____sys_io_uring_register(int fd, unsigned opcode, const void *arg, unsigned nr_args) { +#ifdef LIBURING_NOLIBC + return __arch_impl_io_uring_register(fd, opcode, arg, nr_args); +#else int ret; - ret = syscall(__NR_io_uring_register, fd, opcode, arg, nr_args); return (ret < 0) ? -errno : ret; +#endif } static inline int ____sys_io_uring_setup(unsigned entries, struct io_uring_params *p) { +#ifdef LIBURING_NOLIBC + return __arch_impl_io_uring_setup(entries, p); +#else int ret; - ret = syscall(__NR_io_uring_setup, entries, p); return (ret < 0) ? -errno : ret; +#endif } static inline int ____sys_io_uring_enter2(int fd, unsigned to_submit, unsigned min_complete, unsigned flags, sigset_t *sig, int sz) { +#ifdef LIBURING_NOLIBC + return __arch_impl_io_uring_enter(fd, to_submit, min_complete, flags, + sig, sz); +#else int ret; - ret = syscall(__NR_io_uring_enter, fd, to_submit, min_complete, flags, sig, sz); return (ret < 0) ? -errno : ret; +#endif } static inline int ____sys_io_uring_enter(int fd, unsigned to_submit, @@ -118,50 +141,68 @@ static inline int ____sys_io_uring_enter(int fd, unsigned to_submit, static inline void *uring_mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset) { +#ifdef LIBURING_NOLIBC + return __arch_impl_mmap(addr, length, prot, flags, fd, offset); +#else void *ret; - ret = mmap(addr, length, prot, flags, fd, offset); return (ret == MAP_FAILED) ? ERR_PTR(-errno) : ret; +#endif } static inline int uring_munmap(void *addr, size_t length) { +#ifdef LIBURING_NOLIBC + return __arch_impl_munmap(addr, length); +#else int ret; - ret = munmap(addr, length); return (ret < 0) ? -errno : ret; +#endif } static inline int uring_madvise(void *addr, size_t length, int advice) { +#ifdef LIBURING_NOLIBC + return __arch_impl_madvise(addr, length, advice); +#else int ret; - ret = madvise(addr, length, advice); return (ret < 0) ? -errno : ret; +#endif } static inline int uring_getrlimit(int resource, struct rlimit *rlim) { +#ifdef LIBURING_NOLIBC + return __arch_impl_getrlimit(resource, rlim); +#else int ret; - ret = getrlimit(resource, rlim); return (ret < 0) ? -errno : ret; +#endif } static inline int uring_setrlimit(int resource, const struct rlimit *rlim) { +#ifdef LIBURING_NOLIBC + return __arch_impl_setrlimit(resource, rlim); +#else int ret; - ret = setrlimit(resource, rlim); return (ret < 0) ? -errno : ret; +#endif } static inline int uring_close(int fd) { +#ifdef LIBURING_NOLIBC + return __arch_impl_close(fd); +#else int ret; - ret = close(fd); return (ret < 0) ? -errno : ret; +#endif } #endif -- 2.30.2
