https://github.com/torvalds/linux
Tip revision: f1fcbaa18b28dec10281551dfe6ed3a3ed80e3d6 authored by Linus Torvalds on 14 May 2023, 19:51:40 UTC
Linux 6.4-rc2
Linux 6.4-rc2
Tip revision: f1fcbaa
arch-riscv.h
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* RISCV (32 and 64) specific definitions for NOLIBC
* Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
*/
#ifndef _NOLIBC_ARCH_RISCV_H
#define _NOLIBC_ARCH_RISCV_H
struct sys_stat_struct {
unsigned long st_dev; /* Device. */
unsigned long st_ino; /* File serial number. */
unsigned int st_mode; /* File mode. */
unsigned int st_nlink; /* Link count. */
unsigned int st_uid; /* User ID of the file's owner. */
unsigned int st_gid; /* Group ID of the file's group. */
unsigned long st_rdev; /* Device number, if device. */
unsigned long __pad1;
long st_size; /* Size of file, in bytes. */
int st_blksize; /* Optimal block size for I/O. */
int __pad2;
long st_blocks; /* Number 512-byte blocks allocated. */
long st_atime; /* Time of last access. */
unsigned long st_atime_nsec;
long st_mtime; /* Time of last modification. */
unsigned long st_mtime_nsec;
long st_ctime; /* Time of last status change. */
unsigned long st_ctime_nsec;
unsigned int __unused4;
unsigned int __unused5;
};
#if __riscv_xlen == 64
#define PTRLOG "3"
#define SZREG "8"
#elif __riscv_xlen == 32
#define PTRLOG "2"
#define SZREG "4"
#endif
/* Syscalls for RISCV :
* - stack is 16-byte aligned
* - syscall number is passed in a7
* - arguments are in a0, a1, a2, a3, a4, a5
* - the system call is performed by calling ecall
* - syscall return comes in a0
* - the arguments are cast to long and assigned into the target
* registers which are then simply passed as registers to the asm code,
* so that we don't have to experience issues with register constraints.
*
* On riscv, select() is not implemented so we have to use pselect6().
*/
#define __ARCH_WANT_SYS_PSELECT6
#define my_syscall0(num) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0"); \
\
__asm__ volatile ( \
"ecall\n\t" \
: "=r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall1(num, arg1) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
\
__asm__ volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
\
__asm__ volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
\
__asm__ volatile ( \
"ecall\n\t" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3") = (long)(arg4); \
\
__asm__ volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3") = (long)(arg4); \
register long _arg5 __asm__ ("a4") = (long)(arg5); \
\
__asm__ volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
({ \
register long _num __asm__ ("a7") = (num); \
register long _arg1 __asm__ ("a0") = (long)(arg1); \
register long _arg2 __asm__ ("a1") = (long)(arg2); \
register long _arg3 __asm__ ("a2") = (long)(arg3); \
register long _arg4 __asm__ ("a3") = (long)(arg4); \
register long _arg5 __asm__ ("a4") = (long)(arg5); \
register long _arg6 __asm__ ("a5") = (long)(arg6); \
\
__asm__ volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
char **environ __attribute__((weak));
const unsigned long *_auxv __attribute__((weak));
/* startup code */
void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
{
__asm__ volatile (
".option push\n"
".option norelax\n"
"lla gp, __global_pointer$\n"
".option pop\n"
"lw a0, 0(sp)\n" // argc (a0) was in the stack
"add a1, sp, "SZREG"\n" // argv (a1) = sp
"slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ...
"add a2, a2, "SZREG"\n" // + SZREG (skip null)
"add a2,a2,a1\n" // + argv
"add a3, a2, zero\n" // iterate a3 over envp to find auxv (after NULL)
"0:\n" // do {
"ld a4, 0(a3)\n" // a4 = *a3;
"add a3, a3, "SZREG"\n" // a3 += sizeof(void*);
"bne a4, zero, 0b\n" // } while (a4);
"lui a4, %hi(_auxv)\n" // a4 = &_auxv (high bits)
"sd a3, %lo(_auxv)(a4)\n" // store a3 into _auxv
"lui a3, %hi(environ)\n" // a3 = &environ (high bits)
"sd a2,%lo(environ)(a3)\n" // store envp(a2) into environ
"andi sp,a1,-16\n" // sp must be 16-byte aligned
"call main\n" // main() returns the status code, we'll exit with it.
"li a7, 93\n" // NR_exit == 93
"ecall\n"
);
__builtin_unreachable();
}
#endif // _NOLIBC_ARCH_RISCV_H
