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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ptrace.c (4508B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * OpenRISC ptrace.c
      4 *
      5 * Linux architectural port borrowing liberally from similar works of
      6 * others.  All original copyrights apply as per the original source
      7 * declaration.
      8 *
      9 * Modifications for the OpenRISC architecture:
     10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
     11 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
     12 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
     13 */
     14
     15#include <linux/kernel.h>
     16#include <linux/sched.h>
     17#include <linux/sched/task_stack.h>
     18#include <linux/string.h>
     19
     20#include <linux/mm.h>
     21#include <linux/errno.h>
     22#include <linux/ptrace.h>
     23#include <linux/audit.h>
     24#include <linux/regset.h>
     25#include <linux/elf.h>
     26
     27#include <asm/thread_info.h>
     28#include <asm/page.h>
     29
     30/*
     31 * Copy the thread state to a regset that can be interpreted by userspace.
     32 *
     33 * It doesn't matter what our internal pt_regs structure looks like.  The
     34 * important thing is that we export a consistent view of the thread state
     35 * to userspace.  As such, we need to make sure that the regset remains
     36 * ABI compatible as defined by the struct user_regs_struct:
     37 *
     38 * (Each item is a 32-bit word)
     39 * r0 = 0 (exported for clarity)
     40 * 31 GPRS r1-r31
     41 * PC (Program counter)
     42 * SR (Supervision register)
     43 */
     44static int genregs_get(struct task_struct *target,
     45		       const struct user_regset *regset,
     46		       struct membuf to)
     47{
     48	const struct pt_regs *regs = task_pt_regs(target);
     49
     50	/* r0 */
     51	membuf_zero(&to, 4);
     52	membuf_write(&to, regs->gpr + 1, 31 * 4);
     53	membuf_store(&to, regs->pc);
     54	return membuf_store(&to, regs->sr);
     55}
     56
     57/*
     58 * Set the thread state from a regset passed in via ptrace
     59 */
     60static int genregs_set(struct task_struct *target,
     61		       const struct user_regset *regset,
     62		       unsigned int pos, unsigned int count,
     63		       const void *kbuf, const void __user * ubuf)
     64{
     65	struct pt_regs *regs = task_pt_regs(target);
     66	int ret;
     67
     68	/* ignore r0 */
     69	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
     70	/* r1 - r31 */
     71	if (!ret)
     72		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
     73					 regs->gpr+1, 4, 4*32);
     74	/* PC */
     75	if (!ret)
     76		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
     77				 &regs->pc, 4*32, 4*33);
     78	/*
     79	 * Skip SR and padding... userspace isn't allowed to changes bits in
     80	 * the Supervision register
     81	 */
     82	if (!ret)
     83		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
     84						4*33, -1);
     85
     86	return ret;
     87}
     88
     89/*
     90 * Define the register sets available on OpenRISC under Linux
     91 */
     92enum or1k_regset {
     93	REGSET_GENERAL,
     94};
     95
     96static const struct user_regset or1k_regsets[] = {
     97	[REGSET_GENERAL] = {
     98			    .core_note_type = NT_PRSTATUS,
     99			    .n = ELF_NGREG,
    100			    .size = sizeof(long),
    101			    .align = sizeof(long),
    102			    .regset_get = genregs_get,
    103			    .set = genregs_set,
    104			    },
    105};
    106
    107static const struct user_regset_view user_or1k_native_view = {
    108	.name = "or1k",
    109	.e_machine = EM_OPENRISC,
    110	.regsets = or1k_regsets,
    111	.n = ARRAY_SIZE(or1k_regsets),
    112};
    113
    114const struct user_regset_view *task_user_regset_view(struct task_struct *task)
    115{
    116	return &user_or1k_native_view;
    117}
    118
    119/*
    120 * does not yet catch signals sent when the child dies.
    121 * in exit.c or in signal.c.
    122 */
    123
    124
    125/*
    126 * Called by kernel/ptrace.c when detaching..
    127 *
    128 * Make sure the single step bit is not set.
    129 */
    130void ptrace_disable(struct task_struct *child)
    131{
    132	pr_debug("ptrace_disable(): TODO\n");
    133
    134	user_disable_single_step(child);
    135	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
    136}
    137
    138long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
    139		 unsigned long data)
    140{
    141	int ret;
    142
    143	switch (request) {
    144	default:
    145		ret = ptrace_request(child, request, addr, data);
    146		break;
    147	}
    148
    149	return ret;
    150}
    151
    152/*
    153 * Notification of system call entry/exit
    154 * - triggered by current->work.syscall_trace
    155 */
    156asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
    157{
    158	long ret = 0;
    159
    160	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
    161	    ptrace_report_syscall_entry(regs))
    162		/*
    163		 * Tracing decided this syscall should not happen.
    164		 * We'll return a bogus call number to get an ENOSYS
    165		 * error, but leave the original number in <something>.
    166		 */
    167		ret = -1L;
    168
    169	audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
    170			    regs->gpr[5], regs->gpr[6]);
    171
    172	return ret ? : regs->gpr[11];
    173}
    174
    175asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
    176{
    177	int step;
    178
    179	audit_syscall_exit(regs);
    180
    181	step = test_thread_flag(TIF_SINGLESTEP);
    182	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
    183		ptrace_report_syscall_exit(regs, step);
    184}