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.h (2793B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * Access to user system call parameters and results
      4 *
      5 * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
      6 *
      7 * See asm-generic/syscall.h for descriptions of what we must do here.
      8 */
      9
     10#ifndef _ASM_SYSCALL_H
     11#define _ASM_SYSCALL_H	1
     12
     13#include <uapi/linux/audit.h>
     14#include <linux/sched.h>
     15#include <linux/thread_info.h>
     16
     17/* ftrace syscalls requires exporting the sys_call_table */
     18extern const unsigned long sys_call_table[];
     19extern const unsigned long compat_sys_call_table[];
     20
     21static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
     22{
     23	/*
     24	 * Note that we are returning an int here. That means 0xffffffff, ie.
     25	 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
     26	 * This is important for seccomp so that compat tasks can set r0 = -1
     27	 * to reject the syscall.
     28	 */
     29	if (trap_is_syscall(regs))
     30		return regs->gpr[0];
     31	else
     32		return -1;
     33}
     34
     35static inline void syscall_rollback(struct task_struct *task,
     36				    struct pt_regs *regs)
     37{
     38	regs->gpr[3] = regs->orig_gpr3;
     39}
     40
     41static inline long syscall_get_error(struct task_struct *task,
     42				     struct pt_regs *regs)
     43{
     44	if (trap_is_scv(regs)) {
     45		unsigned long error = regs->gpr[3];
     46
     47		return IS_ERR_VALUE(error) ? error : 0;
     48	} else {
     49		/*
     50		 * If the system call failed,
     51		 * regs->gpr[3] contains a positive ERRORCODE.
     52		 */
     53		return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
     54	}
     55}
     56
     57static inline long syscall_get_return_value(struct task_struct *task,
     58					    struct pt_regs *regs)
     59{
     60	return regs->gpr[3];
     61}
     62
     63static inline void syscall_set_return_value(struct task_struct *task,
     64					    struct pt_regs *regs,
     65					    int error, long val)
     66{
     67	if (trap_is_scv(regs)) {
     68		regs->gpr[3] = (long) error ?: val;
     69	} else {
     70		/*
     71		 * In the general case it's not obvious that we must deal with
     72		 * CCR here, as the syscall exit path will also do that for us.
     73		 * However there are some places, eg. the signal code, which
     74		 * check ccr to decide if the value in r3 is actually an error.
     75		 */
     76		if (error) {
     77			regs->ccr |= 0x10000000L;
     78			regs->gpr[3] = error;
     79		} else {
     80			regs->ccr &= ~0x10000000L;
     81			regs->gpr[3] = val;
     82		}
     83	}
     84}
     85
     86static inline void syscall_get_arguments(struct task_struct *task,
     87					 struct pt_regs *regs,
     88					 unsigned long *args)
     89{
     90	unsigned long val, mask = -1UL;
     91	unsigned int n = 6;
     92
     93	if (is_tsk_32bit_task(task))
     94		mask = 0xffffffff;
     95
     96	while (n--) {
     97		if (n == 0)
     98			val = regs->orig_gpr3;
     99		else
    100			val = regs->gpr[3 + n];
    101
    102		args[n] = val & mask;
    103	}
    104}
    105
    106static inline int syscall_get_arch(struct task_struct *task)
    107{
    108	if (is_tsk_32bit_task(task))
    109		return AUDIT_ARCH_PPC;
    110	else if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
    111		return AUDIT_ARCH_PPC64LE;
    112	else
    113		return AUDIT_ARCH_PPC64;
    114}
    115#endif	/* _ASM_SYSCALL_H */