cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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syscall.c (4430B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 *  S390 version
      4 *    Copyright IBM Corp. 1999, 2000
      5 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
      6 *               Thomas Spatzier (tspat@de.ibm.com)
      7 *
      8 *  Derived from "arch/i386/kernel/sys_i386.c"
      9 *
     10 *  This file contains various random system calls that
     11 *  have a non-standard calling sequence on the Linux/s390
     12 *  platform.
     13 */
     14
     15#include <linux/errno.h>
     16#include <linux/sched.h>
     17#include <linux/mm.h>
     18#include <linux/fs.h>
     19#include <linux/smp.h>
     20#include <linux/sem.h>
     21#include <linux/msg.h>
     22#include <linux/shm.h>
     23#include <linux/stat.h>
     24#include <linux/syscalls.h>
     25#include <linux/mman.h>
     26#include <linux/file.h>
     27#include <linux/utsname.h>
     28#include <linux/personality.h>
     29#include <linux/unistd.h>
     30#include <linux/ipc.h>
     31#include <linux/uaccess.h>
     32#include <linux/string.h>
     33#include <linux/thread_info.h>
     34#include <linux/entry-common.h>
     35
     36#include <asm/ptrace.h>
     37#include <asm/vtime.h>
     38
     39#include "entry.h"
     40
     41/*
     42 * Perform the mmap() system call. Linux for S/390 isn't able to handle more
     43 * than 5 system call parameters, so this system call uses a memory block
     44 * for parameter passing.
     45 */
     46
     47struct s390_mmap_arg_struct {
     48	unsigned long addr;
     49	unsigned long len;
     50	unsigned long prot;
     51	unsigned long flags;
     52	unsigned long fd;
     53	unsigned long offset;
     54};
     55
     56SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
     57{
     58	struct s390_mmap_arg_struct a;
     59	int error = -EFAULT;
     60
     61	if (copy_from_user(&a, arg, sizeof(a)))
     62		goto out;
     63	error = ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
     64out:
     65	return error;
     66}
     67
     68#ifdef CONFIG_SYSVIPC
     69/*
     70 * sys_ipc() is the de-multiplexer for the SysV IPC calls.
     71 */
     72SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
     73		unsigned long, third, void __user *, ptr)
     74{
     75	if (call >> 16)
     76		return -EINVAL;
     77	/* The s390 sys_ipc variant has only five parameters instead of six
     78	 * like the generic variant. The only difference is the handling of
     79	 * the SEMTIMEDOP subcall where on s390 the third parameter is used
     80	 * as a pointer to a struct timespec where the generic variant uses
     81	 * the fifth parameter.
     82	 * Therefore we can call the generic variant by simply passing the
     83	 * third parameter also as fifth parameter.
     84	 */
     85	return ksys_ipc(call, first, second, third, ptr, third);
     86}
     87#endif /* CONFIG_SYSVIPC */
     88
     89SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
     90{
     91	unsigned int ret = current->personality;
     92
     93	if (personality(current->personality) == PER_LINUX32 &&
     94	    personality(personality) == PER_LINUX)
     95		personality |= PER_LINUX32;
     96
     97	if (personality != 0xffffffff)
     98		set_personality(personality);
     99
    100	if (personality(ret) == PER_LINUX32)
    101		ret &= ~PER_LINUX32;
    102
    103	return ret;
    104}
    105
    106SYSCALL_DEFINE0(ni_syscall)
    107{
    108	return -ENOSYS;
    109}
    110
    111static void do_syscall(struct pt_regs *regs)
    112{
    113	unsigned long nr;
    114
    115	nr = regs->int_code & 0xffff;
    116	if (!nr) {
    117		nr = regs->gprs[1] & 0xffff;
    118		regs->int_code &= ~0xffffUL;
    119		regs->int_code |= nr;
    120	}
    121
    122	regs->gprs[2] = nr;
    123
    124	if (nr == __NR_restart_syscall && !(current->restart_block.arch_data & 1)) {
    125		regs->psw.addr = current->restart_block.arch_data;
    126		current->restart_block.arch_data = 1;
    127	}
    128	nr = syscall_enter_from_user_mode_work(regs, nr);
    129
    130	/*
    131	 * In the s390 ptrace ABI, both the syscall number and the return value
    132	 * use gpr2. However, userspace puts the syscall number either in the
    133	 * svc instruction itself, or uses gpr1. To make at least skipping syscalls
    134	 * work, the ptrace code sets PIF_SYSCALL_RET_SET, which is checked here
    135	 * and if set, the syscall will be skipped.
    136	 */
    137
    138	if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
    139		goto out;
    140	regs->gprs[2] = -ENOSYS;
    141	if (likely(nr >= NR_syscalls))
    142		goto out;
    143	do {
    144		regs->gprs[2] = current->thread.sys_call_table[nr](regs);
    145	} while (test_and_clear_pt_regs_flag(regs, PIF_EXECVE_PGSTE_RESTART));
    146out:
    147	syscall_exit_to_user_mode_work(regs);
    148}
    149
    150void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
    151{
    152	add_random_kstack_offset();
    153	enter_from_user_mode(regs);
    154	regs->psw = S390_lowcore.svc_old_psw;
    155	regs->int_code = S390_lowcore.svc_int_code;
    156	update_timer_sys();
    157	if (static_branch_likely(&cpu_has_bear))
    158		current->thread.last_break = regs->last_break;
    159
    160	local_irq_enable();
    161	regs->orig_gpr2 = regs->gprs[2];
    162
    163	if (per_trap)
    164		set_thread_flag(TIF_PER_TRAP);
    165
    166	regs->flags = 0;
    167	set_pt_regs_flag(regs, PIF_SYSCALL);
    168	do_syscall(regs);
    169	exit_to_user_mode();
    170}