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// SPDX-License-Identifier: GPL-2.0+
/*
* Author: Hanlu Li <lihanlu@loongson.cn>
* Huacai Chen <chenhuacai@loongson.cn>
*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/capability.h>
#include <linux/entry-common.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/objtool.h>
#include <linux/randomize_kstack.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <asm/asm.h>
#include <asm/exception.h>
#include <asm/loongarch.h>
#include <asm/signal.h>
#include <asm/switch_to.h>
#include <asm-generic/syscalls.h>
#undef __SYSCALL
#define __SYSCALL(nr, call) [nr] = (call),
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long,
prot, unsigned long, flags, unsigned long, fd, unsigned long, offset)
{
if (offset & ~PAGE_MASK)
return -EINVAL;
return ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
}
void *sys_call_table[__NR_syscalls] = {
[0 ... __NR_syscalls - 1] = sys_ni_syscall,
#include <asm/syscall_table_64.h>
};
typedef long (*sys_call_fn)(unsigned long, unsigned long,
unsigned long, unsigned long, unsigned long, unsigned long);
void noinstr __no_stack_protector do_syscall(struct pt_regs *regs)
{
unsigned long nr;
sys_call_fn syscall_fn;
nr = regs->regs[11];
/* Set for syscall restarting */
if (nr < NR_syscalls)
regs->regs[0] = nr + 1;
regs->csr_era += 4;
regs->orig_a0 = regs->regs[4];
regs->regs[4] = -ENOSYS;
nr = syscall_enter_from_user_mode(regs, nr);
add_random_kstack_offset();
if (nr < NR_syscalls) {
syscall_fn = sys_call_table[nr];
regs->regs[4] = syscall_fn(regs->orig_a0, regs->regs[5], regs->regs[6],
regs->regs[7], regs->regs[8], regs->regs[9]);
}
/*
* This value will get limited by KSTACK_OFFSET_MAX(), which is 10
* bits. The actual entropy will be further reduced by the compiler
* when applying stack alignment constraints: 16-bytes (i.e. 4-bits)
* aligned, which will remove the 4 low bits from any entropy chosen
* here.
*
* The resulting 6 bits of entropy is seen in SP[9:4].
*/
choose_random_kstack_offset(drdtime());
syscall_exit_to_user_mode(regs);
}
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