1 files changed, 433 insertions, 0 deletions

diff --git a/arch/loongarch/kernel/ptrace.c b/arch/loongarch/kernel/ptrace.c
new file mode 100644
index 000000000..dc2b82ea8
--- /dev/null
+++ b/arch/loongarch/kernel/ptrace.c
@@ -0,0 +1,433 @@
+// 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/mm.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/uaccess.h>
+
+#include <asm/byteorder.h>
+#include <asm/cpu.h>
+#include <asm/cpu-info.h>
+#include <asm/fpu.h>
+#include <asm/loongarch.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/processor.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;
+
+	if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
+		r = gfpr_get(target, &to);
+	else
+		r = gfpr_get_simd(target, &to);
+
+	r = membuf_write(&to, &target->thread.fpu.fcc, sizeof(target->thread.fpu.fcc));
+	r = membuf_write(&to, &target->thread.fpu.fcsr, sizeof(target->thread.fpu.fcsr));
+
+	return r;
+}
+
+static int gfpr_set(struct task_struct *target,
+		    unsigned int *pos, unsigned int *count,
+		    const void **kbuf, const void __user **ubuf)
+{
+	return user_regset_copyin(pos, count, kbuf, ubuf,
+				  &target->thread.fpu.fpr,
+				  0, NUM_FPU_REGS * sizeof(elf_fpreg_t));
+}
+
+static int gfpr_set_simd(struct task_struct *target,
+		       unsigned int *pos, unsigned int *count,
+		       const void **kbuf, const void __user **ubuf)
+{
+	int i, err;
+	u64 fpr_val;
+
+	BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
+	for (i = 0; i < NUM_FPU_REGS && *count > 0; i++) {
+		err = user_regset_copyin(pos, count, kbuf, ubuf,
+					 &fpr_val, i * sizeof(elf_fpreg_t),
+					 (i + 1) * sizeof(elf_fpreg_t));
+		if (err)
+			return err;
+		set_fpr64(&target->thread.fpu.fpr[i], 0, fpr_val);
+	}
+
+	return 0;
+}
+
+/*
+ * Choose the appropriate helper for general registers, and then copy
+ * the FCC register separately.
+ */
+static int fpr_set(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	const int fcc_start = NUM_FPU_REGS * sizeof(elf_fpreg_t);
+	const int fcsr_start = fcc_start + sizeof(u64);
+	int err;
+
+	BUG_ON(count % sizeof(elf_fpreg_t));
+	if (pos + count > sizeof(elf_fpregset_t))
+		return -EIO;
+
+	init_fp_ctx(target);
+
+	if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
+		err = gfpr_set(target, &pos, &count, &kbuf, &ubuf);
+	else
+		err = gfpr_set_simd(target, &pos, &count, &kbuf, &ubuf);
+	if (err)
+		return err;
+
+	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				  &target->thread.fpu.fcc, fcc_start,
+				  fcc_start + sizeof(u64));
+	err |= user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				  &target->thread.fpu.fcsr, fcsr_start,
+				  fcsr_start + sizeof(u32));
+
+	return err;
+}
+
+static int cfg_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   struct membuf to)
+{
+	int i, r;
+	u32 cfg_val;
+
+	i = 0;
+	while (to.left > 0) {
+		cfg_val = read_cpucfg(i++);
+		r = membuf_write(&to, &cfg_val, sizeof(u32));
+	}
+
+	return r;
+}
+
+/*
+ * CFG registers are read-only.
+ */
+static int cfg_set(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	return 0;
+}
+
+struct pt_regs_offset {
+	const char *name;
+	int offset;
+};
+
+#define REG_OFFSET_NAME(n, r) {.name = #n, .offset = offsetof(struct pt_regs, r)}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+	REG_OFFSET_NAME(r0, regs[0]),
+	REG_OFFSET_NAME(r1, regs[1]),
+	REG_OFFSET_NAME(r2, regs[2]),
+	REG_OFFSET_NAME(r3, regs[3]),
+	REG_OFFSET_NAME(r4, regs[4]),
+	REG_OFFSET_NAME(r5, regs[5]),
+	REG_OFFSET_NAME(r6, regs[6]),
+	REG_OFFSET_NAME(r7, regs[7]),
+	REG_OFFSET_NAME(r8, regs[8]),
+	REG_OFFSET_NAME(r9, regs[9]),
+	REG_OFFSET_NAME(r10, regs[10]),
+	REG_OFFSET_NAME(r11, regs[11]),
+	REG_OFFSET_NAME(r12, regs[12]),
+	REG_OFFSET_NAME(r13, regs[13]),
+	REG_OFFSET_NAME(r14, regs[14]),
+	REG_OFFSET_NAME(r15, regs[15]),
+	REG_OFFSET_NAME(r16, regs[16]),
+	REG_OFFSET_NAME(r17, regs[17]),
+	REG_OFFSET_NAME(r18, regs[18]),
+	REG_OFFSET_NAME(r19, regs[19]),
+	REG_OFFSET_NAME(r20, regs[20]),
+	REG_OFFSET_NAME(r21, regs[21]),
+	REG_OFFSET_NAME(r22, regs[22]),
+	REG_OFFSET_NAME(r23, regs[23]),
+	REG_OFFSET_NAME(r24, regs[24]),
+	REG_OFFSET_NAME(r25, regs[25]),
+	REG_OFFSET_NAME(r26, regs[26]),
+	REG_OFFSET_NAME(r27, regs[27]),
+	REG_OFFSET_NAME(r28, regs[28]),
+	REG_OFFSET_NAME(r29, regs[29]),
+	REG_OFFSET_NAME(r30, regs[30]),
+	REG_OFFSET_NAME(r31, regs[31]),
+	REG_OFFSET_NAME(orig_a0, orig_a0),
+	REG_OFFSET_NAME(csr_era, csr_era),
+	REG_OFFSET_NAME(csr_badvaddr, csr_badvaddr),
+	REG_OFFSET_NAME(csr_crmd, csr_crmd),
+	REG_OFFSET_NAME(csr_prmd, csr_prmd),
+	REG_OFFSET_NAME(csr_euen, csr_euen),
+	REG_OFFSET_NAME(csr_ecfg, csr_ecfg),
+	REG_OFFSET_NAME(csr_estat, csr_estat),
+	REG_OFFSET_END,
+};
+
+/**
+ * regs_query_register_offset() - query register offset from its name
+ * @name:       the name of a register
+ *
+ * regs_query_register_offset() returns the offset of a register in struct
+ * pt_regs from its name. If the name is invalid, this returns -EINVAL;
+ */
+int regs_query_register_offset(const char *name)
+{
+	const struct pt_regs_offset *roff;
+
+	for (roff = regoffset_table; roff->name != NULL; roff++)
+		if (!strcmp(roff->name, name))
+			return roff->offset;
+	return -EINVAL;
+}
+
+enum loongarch_regset {
+	REGSET_GPR,
+	REGSET_FPR,
+	REGSET_CPUCFG,
+};
+
+static const struct user_regset loongarch64_regsets[] = {
+	[REGSET_GPR] = {
+		.core_note_type	= NT_PRSTATUS,
+		.n		= ELF_NGREG,
+		.size		= sizeof(elf_greg_t),
+		.align		= sizeof(elf_greg_t),
+		.regset_get	= gpr_get,
+		.set		= gpr_set,
+	},
+	[REGSET_FPR] = {
+		.core_note_type	= NT_PRFPREG,
+		.n		= ELF_NFPREG,
+		.size		= sizeof(elf_fpreg_t),
+		.align		= sizeof(elf_fpreg_t),
+		.regset_get	= fpr_get,
+		.set		= fpr_set,
+	},
+	[REGSET_CPUCFG] = {
+		.core_note_type	= NT_LOONGARCH_CPUCFG,
+		.n		= 64,
+		.size		= sizeof(u32),
+		.align		= sizeof(u32),
+		.regset_get	= cfg_get,
+		.set		= cfg_set,
+	},
+};
+
+static const struct user_regset_view user_loongarch64_view = {
+	.name		= "loongarch64",
+	.e_machine	= ELF_ARCH,
+	.regsets	= loongarch64_regsets,
+	.n		= ARRAY_SIZE(loongarch64_regsets),
+};
+
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &user_loongarch64_view;
+}
+
+static inline int read_user(struct task_struct *target, unsigned long addr,
+			    unsigned long __user *data)
+{
+	unsigned long tmp = 0;
+
+	switch (addr) {
+	case 0 ... 31:
+		tmp = task_pt_regs(target)->regs[addr];
+		break;
+	case ARG0:
+		tmp = task_pt_regs(target)->orig_a0;
+		break;
+	case PC:
+		tmp = task_pt_regs(target)->csr_era;
+		break;
+	case BADVADDR:
+		tmp = task_pt_regs(target)->csr_badvaddr;
+		break;
+	default:
+		return -EIO;
+	}
+
+	return put_user(tmp, data);
+}
+
+static inline int write_user(struct task_struct *target, unsigned long addr,
+			    unsigned long data)
+{
+	switch (addr) {
+	case 0 ... 31:
+		task_pt_regs(target)->regs[addr] = data;
+		break;
+	case ARG0:
+		task_pt_regs(target)->orig_a0 = data;
+		break;
+	case PC:
+		task_pt_regs(target)->csr_era = data;
+		break;
+	case BADVADDR:
+		task_pt_regs(target)->csr_badvaddr = data;
+		break;
+	default:
+		return -EIO;
+	}
+
+	return 0;
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	int ret;
+	unsigned long __user *datap = (void __user *) data;
+
+	switch (request) {
+	case PTRACE_PEEKUSR:
+		ret = read_user(child, addr, datap);
+		break;
+
+	case PTRACE_POKEUSR:
+		ret = write_user(child, addr, data);
+		break;
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}