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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); } #ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET STACK_FRAME_NON_STANDARD(do_syscall); #endif |