96 lines
1.8 KiB
C
96 lines
1.8 KiB
C
// An extremely minimalist syscalls.c for newlib
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// Based on riscv newlib libgloss/riscv/sys_*.c
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// Written by Clifford Wolf.
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#include <sys/stat.h>
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#include <unistd.h>
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#include <errno.h>
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#define UNIMPL_FUNC(_f) ".globl " #_f "\n.type " #_f ", @function\n" #_f ":\n"
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asm (
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".text\n"
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".align 2\n"
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UNIMPL_FUNC(_open)
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UNIMPL_FUNC(_openat)
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UNIMPL_FUNC(_lseek)
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UNIMPL_FUNC(_stat)
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UNIMPL_FUNC(_lstat)
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UNIMPL_FUNC(_fstatat)
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UNIMPL_FUNC(_isatty)
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UNIMPL_FUNC(_access)
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UNIMPL_FUNC(_faccessat)
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UNIMPL_FUNC(_link)
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UNIMPL_FUNC(_unlink)
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UNIMPL_FUNC(_execve)
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UNIMPL_FUNC(_getpid)
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UNIMPL_FUNC(_fork)
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UNIMPL_FUNC(_kill)
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UNIMPL_FUNC(_wait)
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UNIMPL_FUNC(_times)
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UNIMPL_FUNC(_gettimeofday)
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UNIMPL_FUNC(_ftime)
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UNIMPL_FUNC(_utime)
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UNIMPL_FUNC(_chown)
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UNIMPL_FUNC(_chmod)
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UNIMPL_FUNC(_chdir)
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UNIMPL_FUNC(_getcwd)
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UNIMPL_FUNC(_sysconf)
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"j unimplemented_syscall\n"
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);
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void unimplemented_syscall()
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{
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const char *p = "Unimplemented system call called!\n";
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while (*p)
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*(volatile int*)0x10000000 = *(p++);
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asm volatile ("ebreak");
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__builtin_unreachable();
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}
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ssize_t _read(int file, void *ptr, size_t len)
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{
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// always EOF
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return 0;
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}
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ssize_t _write(int file, const void *ptr, size_t len)
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{
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const void *eptr = ptr + len;
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while (ptr != eptr)
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*(volatile int*)0x10000000 = *(char*)(ptr++);
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return len;
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}
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int _close(int file)
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{
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// close is called before _exit()
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return 0;
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}
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int _fstat(int file, struct stat *st)
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{
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// fstat is called during libc startup
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errno = ENOENT;
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return -1;
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}
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void *_sbrk(ptrdiff_t incr)
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{
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extern unsigned char _end[]; // Defined by linker
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static unsigned long heap_end;
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if (heap_end == 0)
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heap_end = (long)_end;
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heap_end += incr;
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return (void *)(heap_end - incr);
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}
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void _exit(int exit_status)
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{
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asm volatile ("ebreak");
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__builtin_unreachable();
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}
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