tools/nolibc: Add support for LoongArch (73f12c6d) · Commits · jan.koester / Linux

tools/include/nolibc/arch-loongarch.h

0 → 100644

+200 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
		/*
		* LoongArch specific definitions for NOLIBC
		* Copyright (C) 2023 Loongson Technology Corporation Limited
		*/

		#ifndef _NOLIBC_ARCH_LOONGARCH_H
		#define _NOLIBC_ARCH_LOONGARCH_H

		/* Syscalls for LoongArch :
		* - 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 "syscall 0"
		* - 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 LoongArch, 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 ( \
		"syscall 0\n" \
		: "=r"(_arg1) \
		: "r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_arg1; \
		})

		#define my_syscall1(num, arg1) \
		({ \
		register long _num __asm__ ("a7") = (num); \
		register long _arg1 __asm__ ("a0") = (long)(arg1); \
		\
		__asm__ volatile ( \
		"syscall 0\n" \
		: "+r"(_arg1) \
		: "r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_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 ( \
		"syscall 0\n" \
		: "+r"(_arg1) \
		: "r"(_arg2), \
		"r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_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 ( \
		"syscall 0\n" \
		: "+r"(_arg1) \
		: "r"(_arg2), "r"(_arg3), \
		"r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_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 ( \
		"syscall 0\n" \
		: "+r"(_arg1) \
		: "r"(_arg2), "r"(_arg3), "r"(_arg4), \
		"r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_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 ( \
		"syscall 0\n" \
		: "+r"(_arg1) \
		: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
		"r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_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 ( \
		"syscall 0\n" \
		: "+r"(_arg1) \
		: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
		"r"(_num) \
		: "memory", "$t0", "$t1", "$t2", "$t3", \
		"$t4", "$t5", "$t6", "$t7", "$t8" \
		); \
		_arg1; \
		})

		char **environ __attribute__((weak));
		const unsigned long *_auxv __attribute__((weak));

		#if __loongarch_grlen == 32
		#define LONGLOG "2"
		#define SZREG "4"
		#define REG_L "ld.w"
		#define LONG_S "st.w"
		#define LONG_ADD "add.w"
		#define LONG_ADDI "addi.w"
		#define LONG_SLL "slli.w"
		#define LONG_BSTRINS "bstrins.w"
		#else // __loongarch_grlen == 64
		#define LONGLOG "3"
		#define SZREG "8"
		#define REG_L "ld.d"
		#define LONG_S "st.d"
		#define LONG_ADD "add.d"
		#define LONG_ADDI "addi.d"
		#define LONG_SLL "slli.d"
		#define LONG_BSTRINS "bstrins.d"
		#endif

		/* startup code */
		void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
		{
		__asm__ volatile (
		REG_L " $a0, $sp, 0\n" // argc (a0) was in the stack
		LONG_ADDI " $a1, $sp, "SZREG"\n" // argv (a1) = sp + SZREG
		LONG_SLL " $a2, $a0, "LONGLOG"\n" // envp (a2) = SZREG*argc ...
		LONG_ADDI " $a2, $a2, "SZREG"\n" // + SZREG (skip null)
		LONG_ADD " $a2, $a2, $a1\n" // + argv

		"move $a3, $a2\n" // iterate a3 over envp to find auxv (after NULL)
		"0:\n" // do {
		REG_L " $a4, $a3, 0\n" // a4 = *a3;
		LONG_ADDI " $a3, $a3, "SZREG"\n" // a3 += sizeof(void*);
		"bne $a4, $zero, 0b\n" // } while (a4);
		"la.pcrel $a4, _auxv\n" // a4 = &_auxv
		LONG_S " $a3, $a4, 0\n" // store a3 into _auxv

		"la.pcrel $a3, environ\n" // a3 = &environ
		LONG_S " $a2, $a3, 0\n" // store envp(a2) into environ
		LONG_BSTRINS " $sp, $zero, 3, 0\n" // sp must be 16-byte aligned
		"bl main\n" // main() returns the status code, we'll exit with it.
		"li.w $a7, 93\n" // NR_exit == 93
		"syscall 0\n"
		);
		__builtin_unreachable();
		}

		#endif // _NOLIBC_ARCH_LOONGARCH_H

tools/include/nolibc/arch.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -29,6 +29,8 @@
		#include "arch-riscv.h"
		#elif defined(__s390x__)
		#include "arch-s390.h"
		#elif defined(__loongarch__)
		#include "arch-loongarch.h"
		#endif

		#endif /* _NOLIBC_ARCH_H */