path: root/arch/loongarch/kernel/ptrace.c

// 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
 *
 * Derived from MIPS:
 * Copyright (C) 1992 Ross Biro
 * Copyright (C) Linus Torvalds
 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
 * Copyright (C) 1996 David S. Miller
 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 1999 MIPS Technologies, Inc.
 * Copyright (C) 2000 Ulf Carlsson
 */
#include <linux/kernel.h>
#include <linux/audit.h>
#include <linux/compiler.h>
#include <linux/context_tracking.h>
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/hw_breakpoint.h>
#include <linux/mm.h>
#include <linux/nospec.h>
#include <linux/ptrace.h>
#include <linux/regset.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/security.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/seccomp.h>
#include <linux/thread_info.h>
#include <linux/uaccess.h>

#include <asm/byteorder.h>
#include <asm/cpu.h>
#include <asm/cpu-info.h>
#include <asm/fpu.h>
#include <asm/lbt.h>
#include <asm/loongarch.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/reg.h>
#include <asm/syscall.h>

static void init_fp_ctx(struct task_struct *target)
{
	/* The target already has context */
	if (tsk_used_math(target))
		return;

	/* Begin with data registers set to all 1s... */
	memset(&target->thread.fpu.fpr, ~0, sizeof(target->thread.fpu.fpr));
	set_stopped_child_used_math(target);
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* Don't load the watchpoint registers for the ex-child. */
	clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
}

/* regset get/set implementations */

static int gpr_get(struct task_struct *target,
		   const struct user_regset *regset,
		   struct membuf to)
{
	int r;
	struct pt_regs *regs = task_pt_regs(target);

	r = membuf_write(&to, &regs->regs, sizeof(u64) * GPR_NUM);
	r = membuf_write(&to, &regs->orig_a0, sizeof(u64));
	r = membuf_write(&to, &regs->csr_era, sizeof(u64));
	r = membuf_write(&to, &regs->csr_badvaddr, sizeof(u64));

	return r;
}

static int gpr_set(struct task_struct *target,
		   const struct user_regset *regset,
		   unsigned int pos, unsigned int count,
		   const void *kbuf, const void __user *ubuf)
{
	int err;
	int a0_start = sizeof(u64) * GPR_NUM;
	int era_start = a0_start + sizeof(u64);
	int badvaddr_start = era_start + sizeof(u64);
	struct pt_regs *regs = task_pt_regs(target);

	err = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &regs->regs,
				 0, a0_start);
	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &regs->orig_a0,
				 a0_start, a0_start + sizeof(u64));
	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &regs->csr_era,
				 era_start, era_start + sizeof(u64));
	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &regs->csr_badvaddr,
				 badvaddr_start, badvaddr_start + sizeof(u64));

	return err;
}


/*
 * Get the general floating-point registers.
 */
static int gfpr_get(struct task_struct *target, struct membuf *to)
{
	return membuf_write(to, &target->thread.fpu.fpr,
			    sizeof(elf_fpreg_t) * NUM_FPU_REGS);
}

static int gfpr_get_simd(struct task_struct *target, struct membuf *to)
{
	int i, r;
	u64 fpr_val;

	BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
	for (i = 0; i < NUM_FPU_REGS; i++) {
		fpr_val = get_fpr64(&target->thread.fpu.fpr[i], 0);
		r = membuf_write(to, &fpr_val, sizeof(elf_fpreg_t));
	}

	return r;
}

/*
 * Choose the appropriate helper for general registers, and then copy
 * the FCC and FCSR registers separately.
 */
static int fpr_get(struct task_struct *target,
		   const struct user_regset *regset,
		   struct membuf to)
{
	int r;

	save_fpu_regs(target);

	if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
		r