diff options
Diffstat (limited to 'lib/include')
| -rw-r--r-- | lib/include/alloc.h | 6 | ||||
| -rw-r--r-- | lib/include/auxv.h | 2 | ||||
| -rw-r--r-- | lib/include/common.h | 18 | ||||
| -rw-r--r-- | lib/include/syscall.h | 33 | ||||
| -rw-r--r-- | lib/include/syscalls.h | 23 |
5 files changed, 62 insertions, 20 deletions
diff --git a/lib/include/alloc.h b/lib/include/alloc.h new file mode 100644 index 0000000..baf8d3d --- /dev/null +++ b/lib/include/alloc.h @@ -0,0 +1,6 @@ +// Copyright (c) 2021 Johannes Stoelp + +#pragma once + +void* alloc(unsigned size); +void dealloc(void* ptr); diff --git a/lib/include/auxv.h b/lib/include/auxv.h index 42dac38..1ac953e 100644 --- a/lib/include/auxv.h +++ b/lib/include/auxv.h @@ -15,7 +15,7 @@ #define AT_EXECFD 2 /* [val] File descriptor of user program (in case Linux Kernel didn't mapped) */ #define AT_PHDR 3 /* [ptr] Address of Phdr of use program (in case Kernel mapped user program) */ #define AT_PHENT 4 /* [val] Size in bytes of one Phdr entry */ -#define AT_PHNUM 5 /* [val] Number of Phread entries */ +#define AT_PHNUM 5 /* [val] Number of Phdr entries */ #define AT_PAGESZ 6 /* [val] System page size */ #define AT_BASE 7 /* [ptr] `base address` interpreter was loaded to */ #define AT_FLAGS 8 /* [val] */ diff --git a/lib/include/common.h b/lib/include/common.h index 5ea6050..631c25f 100644 --- a/lib/include/common.h +++ b/lib/include/common.h @@ -3,14 +3,12 @@ #pragma once #include "io.h" -#include "syscall.h" - -#include <asm/unistd.h> - -#define ERROR_ON(cond, ...) \ - do { \ - if ((cond)) { \ - efmt(__VA_ARGS__); \ - syscall1(__NR_exit, 1); \ - } \ +#include "syscalls.h" + +#define ERROR_ON(cond, fmt, ...) \ + do { \ + if ((cond)) { \ + efmt("%s:%d " fmt, __FILE__, __LINE__ __VA_OPT__(, ) __VA_ARGS__); \ + _exit(1); \ + } \ } while (0) diff --git a/lib/include/syscall.h b/lib/include/syscall.h index 4947155..c9314d2 100644 --- a/lib/include/syscall.h +++ b/lib/include/syscall.h @@ -35,29 +35,44 @@ // https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html // https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html#Machine-Constraints // https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html - -// Linux syscall ABI -// x86-64 -// #syscall: rax -// ret : rax -// instr : syscall -// args : rdi rsi rdx r10 r8 r9 +// +// +// Linux syscall ABI - x86-64 +// #syscall: rax +// ret : rax +// instr : syscall +// args : rdi rsi rdx r10 r8 r9 // // Reference: // syscall(2) +// +// +// X86_64 `syscall` instruction additionally clobbers following registers: +// rcx Store return address. +// r11 Store RFLAGS. +// +// Reference: +// https://www.felixcloutier.com/x86/syscall #define argcast(A) ((long)(A)) #define syscall1(n, a1) _syscall1(n, argcast(a1)) +#define syscall2(n, a1, a2) _syscall2(n, argcast(a1), argcast(a2)) #define syscall3(n, a1, a2, a3) _syscall3(n, argcast(a1), argcast(a2), argcast(a3)) static inline long _syscall1(long n, long a1) { long ret; - asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1) : "memory"); + asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1) : "rcx", "r11", "memory"); + return ret; +} + +static inline long _syscall2(long n, long a1, long a2) { + long ret; + asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2) : "rcx", "r11", "memory"); return ret; } static inline long _syscall3(long n, long a1, long a2, long a3) { long ret; - asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), "d"(a3) : "memory"); + asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), "d"(a3) : "rcx", "r11", "memory"); return ret; } diff --git a/lib/include/syscalls.h b/lib/include/syscalls.h new file mode 100644 index 0000000..34b6b37 --- /dev/null +++ b/lib/include/syscalls.h @@ -0,0 +1,23 @@ +// Copyright (c) 2021 Johannes Stoelp + +#pragma once + +#include <stddef.h> // size_t +#include <sys/types.h> // ssize_t, off_t, ... + +// Syscall definitions taken from corresponding man pages, eg +// open(2) +// read(2) +// ... + +#define O_RDONLY 00 +int open(const char* path, int flags); + +ssize_t read(int fd, void* buf, size_t count); + +#define SEEK_SET 0 +#define SEEK_CUR 1 +#define SEEK_END 2 +off_t lseek(int fd, off_t offset, int whence); + +void _exit(int status); |