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In the _start block we now iterate over envp to find the auxiliary vector after the NULL. The pointer is saved into an _auxv variable that is marked as weak so that it's accessible from multiple units. It was tested on riscv64 only. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
209 lines
10 KiB
C
209 lines
10 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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/*
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* RISCV (32 and 64) specific definitions for NOLIBC
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* Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
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*/
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#ifndef _NOLIBC_ARCH_RISCV_H
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#define _NOLIBC_ARCH_RISCV_H
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struct sys_stat_struct {
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unsigned long st_dev; /* Device. */
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unsigned long st_ino; /* File serial number. */
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unsigned int st_mode; /* File mode. */
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unsigned int st_nlink; /* Link count. */
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unsigned int st_uid; /* User ID of the file's owner. */
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unsigned int st_gid; /* Group ID of the file's group. */
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unsigned long st_rdev; /* Device number, if device. */
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unsigned long __pad1;
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long st_size; /* Size of file, in bytes. */
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int st_blksize; /* Optimal block size for I/O. */
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int __pad2;
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long st_blocks; /* Number 512-byte blocks allocated. */
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long st_atime; /* Time of last access. */
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unsigned long st_atime_nsec;
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long st_mtime; /* Time of last modification. */
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unsigned long st_mtime_nsec;
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long st_ctime; /* Time of last status change. */
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unsigned long st_ctime_nsec;
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unsigned int __unused4;
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unsigned int __unused5;
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};
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#if __riscv_xlen == 64
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#define PTRLOG "3"
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#define SZREG "8"
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#elif __riscv_xlen == 32
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#define PTRLOG "2"
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#define SZREG "4"
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#endif
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/* Syscalls for RISCV :
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* - stack is 16-byte aligned
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* - syscall number is passed in a7
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* - arguments are in a0, a1, a2, a3, a4, a5
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* - the system call is performed by calling ecall
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* - syscall return comes in a0
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* - the arguments are cast to long and assigned into the target
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* registers which are then simply passed as registers to the asm code,
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* so that we don't have to experience issues with register constraints.
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*
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* On riscv, select() is not implemented so we have to use pselect6().
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*/
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#define __ARCH_WANT_SYS_PSELECT6
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#define my_syscall0(num) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0"); \
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\
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__asm__ volatile ( \
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"ecall\n\t" \
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: "=r"(_arg1) \
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: "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall1(num, arg1) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0") = (long)(arg1); \
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\
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__asm__ volatile ( \
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"ecall\n" \
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: "+r"(_arg1) \
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: "r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall2(num, arg1, arg2) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0") = (long)(arg1); \
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register long _arg2 __asm__ ("a1") = (long)(arg2); \
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\
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__asm__ volatile ( \
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"ecall\n" \
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: "+r"(_arg1) \
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: "r"(_arg2), \
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"r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall3(num, arg1, arg2, arg3) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0") = (long)(arg1); \
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register long _arg2 __asm__ ("a1") = (long)(arg2); \
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register long _arg3 __asm__ ("a2") = (long)(arg3); \
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\
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__asm__ volatile ( \
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"ecall\n\t" \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), \
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"r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall4(num, arg1, arg2, arg3, arg4) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0") = (long)(arg1); \
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register long _arg2 __asm__ ("a1") = (long)(arg2); \
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register long _arg3 __asm__ ("a2") = (long)(arg3); \
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register long _arg4 __asm__ ("a3") = (long)(arg4); \
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\
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__asm__ volatile ( \
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"ecall\n" \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_arg4), \
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"r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0") = (long)(arg1); \
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register long _arg2 __asm__ ("a1") = (long)(arg2); \
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register long _arg3 __asm__ ("a2") = (long)(arg3); \
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register long _arg4 __asm__ ("a3") = (long)(arg4); \
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register long _arg5 __asm__ ("a4") = (long)(arg5); \
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\
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__asm__ volatile ( \
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"ecall\n" \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
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"r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
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({ \
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register long _num __asm__ ("a7") = (num); \
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register long _arg1 __asm__ ("a0") = (long)(arg1); \
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register long _arg2 __asm__ ("a1") = (long)(arg2); \
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register long _arg3 __asm__ ("a2") = (long)(arg3); \
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register long _arg4 __asm__ ("a3") = (long)(arg4); \
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register long _arg5 __asm__ ("a4") = (long)(arg5); \
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register long _arg6 __asm__ ("a5") = (long)(arg6); \
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\
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__asm__ volatile ( \
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"ecall\n" \
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: "+r"(_arg1) \
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: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
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"r"(_num) \
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: "memory", "cc" \
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); \
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_arg1; \
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})
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char **environ __attribute__((weak));
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const unsigned long *_auxv __attribute__((weak));
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/* startup code */
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void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
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{
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__asm__ volatile (
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".option push\n"
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".option norelax\n"
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"lla gp, __global_pointer$\n"
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".option pop\n"
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"lw a0, 0(sp)\n" // argc (a0) was in the stack
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"add a1, sp, "SZREG"\n" // argv (a1) = sp
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"slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ...
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"add a2, a2, "SZREG"\n" // + SZREG (skip null)
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"add a2,a2,a1\n" // + argv
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"add a3, a2, zero\n" // iterate a3 over envp to find auxv (after NULL)
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"0:\n" // do {
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"ld a4, 0(a3)\n" // a4 = *a3;
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"add a3, a3, "SZREG"\n" // a3 += sizeof(void*);
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"bne a4, zero, 0b\n" // } while (a4);
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"lui a4, %hi(_auxv)\n" // a4 = &_auxv (high bits)
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"sd a3, %lo(_auxv)(a4)\n" // store a3 into _auxv
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"lui a3, %hi(environ)\n" // a3 = &environ (high bits)
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"sd a2,%lo(environ)(a3)\n" // store envp(a2) into environ
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"andi sp,a1,-16\n" // sp must be 16-byte aligned
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"call main\n" // main() returns the status code, we'll exit with it.
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"li a7, 93\n" // NR_exit == 93
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"ecall\n"
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);
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__builtin_unreachable();
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}
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#endif // _NOLIBC_ARCH_RISCV_H
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