arch/riscv/kernel/ptrace.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2010 Tilera Corporation. All Rights Reserved.
  * Copyright 2015 Regents of the University of California
  * Copyright 2017 SiFive
  *
  * Copied from arch/tile/kernel/ptrace.c
  */

 #include <asm/ptrace.h>
 #include <asm/syscall.h>
 #include <asm/thread_info.h>
 #include <asm/switch_to.h>
 #include <linux/audit.h>
 #include <linux/ptrace.h>
 #include <linux/elf.h>
 #include <linux/regset.h>
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
 #include <linux/tracehook.h>

 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>

 enum riscv_regset {
 	REGSET_X,
 #ifdef CONFIG_FPU
 	REGSET_F,
 #endif
 };

 static int riscv_gpr_get(struct task_struct *target,
 			 const struct user_regset *regset,
 			 struct membuf to)
 {
 	return membuf_write(&to, task_pt_regs(target),
 			    sizeof(struct user_regs_struct));
 }

 static int riscv_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 ret;
 	struct pt_regs *regs;

 	regs = task_pt_regs(target);
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
 	return ret;
 }

 #ifdef CONFIG_FPU
 static int riscv_fpr_get(struct task_struct *target,
 			 const struct user_regset *regset,
 			 struct membuf to)
 {
 	struct __riscv_d_ext_state *fstate = &target->thread.fstate;

 	if (target == current)
 		fstate_save(current, task_pt_regs(current));

 	membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
 	membuf_store(&to, fstate->fcsr);
 	return membuf_zero(&to, 4);	// explicitly pad
 }

 static int riscv_fpr_set(struct task_struct *target,
 			 const struct user_regset *regset,
 			 unsigned int pos, unsigned int count,
 			 const void *kbuf, const void __user *ubuf)
 {
 	int ret;
 	struct __riscv_d_ext_state *fstate = &target->thread.fstate;

 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
 				 offsetof(struct __riscv_d_ext_state, fcsr));
 	if (!ret) {
 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
 					 offsetof(struct __riscv_d_ext_state, fcsr) +
 					 sizeof(fstate->fcsr));
 	}

 	return ret;
 }
 #endif

 static const struct user_regset riscv_user_regset[] = {
 	[REGSET_X] = {
 		.core_note_type = NT_PRSTATUS,
 		.n = ELF_NGREG,
 		.size = sizeof(elf_greg_t),
 		.align = sizeof(elf_greg_t),
 		.regset_get = riscv_gpr_get,
 		.set = riscv_gpr_set,
 	},
 #ifdef CONFIG_FPU
 	[REGSET_F] = {
 		.core_note_type = NT_PRFPREG,
 		.n = ELF_NFPREG,
 		.size = sizeof(elf_fpreg_t),
 		.align = sizeof(elf_fpreg_t),
 		.regset_get = riscv_fpr_get,
 		.set = riscv_fpr_set,
 	},
 #endif
 };

 static const struct user_regset_view riscv_user_native_view = {
 	.name = "riscv",
 	.e_machine = EM_RISCV,
 	.regsets = riscv_user_regset,
 	.n = ARRAY_SIZE(riscv_user_regset),
 };

 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 {
 	return &riscv_user_native_view;
 }

 struct pt_regs_offset {
 	const char *name;
 	int offset;
 };

 #define REG_OFFSET_NAME(r) {.name = #r, .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(epc),
 	REG_OFFSET_NAME(ra),
 	REG_OFFSET_NAME(sp),
 	REG_OFFSET_NAME(gp),
 	REG_OFFSET_NAME(tp),
 	REG_OFFSET_NAME(t0),
 	REG_OFFSET_NAME(t1),
 	REG_OFFSET_NAME(t2),
 	REG_OFFSET_NAME(s0),
 	REG_OFFSET_NAME(s1),
 	REG_OFFSET_NAME(a0),
 	REG_OFFSET_NAME(a1),
 	REG_OFFSET_NAME(a2),
 	REG_OFFSET_NAME(a3),
 	REG_OFFSET_NAME(a4),
 	REG_OFFSET_NAME(a5),
 	REG_OFFSET_NAME(a6),
 	REG_OFFSET_NAME(a7),
 	REG_OFFSET_NAME(s2),
 	REG_OFFSET_NAME(s3),
 	REG_OFFSET_NAME(s4),
 	REG_OFFSET_NAME(s5),
 	REG_OFFSET_NAME(s6),
 	REG_OFFSET_NAME(s7),
 	REG_OFFSET_NAME(s8),
 	REG_OFFSET_NAME(s9),
 	REG_OFFSET_NAME(s10),
 	REG_OFFSET_NAME(s11),
 	REG_OFFSET_NAME(t3),
 	REG_OFFSET_NAME(t4),
 	REG_OFFSET_NAME(t5),
 	REG_OFFSET_NAME(t6),
 	REG_OFFSET_NAME(status),
 	REG_OFFSET_NAME(badaddr),
 	REG_OFFSET_NAME(cause),
 	REG_OFFSET_NAME(orig_a0),
 	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;
 }

 /**
  * regs_within_kernel_stack() - check the address in the stack
  * @regs:      pt_regs which contains kernel stack pointer.
  * @addr:      address which is checked.
  *
  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
  * If @addr is within the kernel stack, it returns true. If not, returns false.
  */
 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 {
 	return (addr & ~(THREAD_SIZE - 1))  ==
 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
 }

 /**
  * regs_get_kernel_stack_nth() - get Nth entry of the stack
  * @regs:	pt_regs which contains kernel stack pointer.
  * @n:		stack entry number.
  *
  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
  * this returns 0.
  */
 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 {
 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);

 	addr += n;
 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
 		return *addr;
 	else
 		return 0;
 }

 void ptrace_disable(struct task_struct *child)
 {
 	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 }

 long arch_ptrace(struct task_struct *child, long request,
 		 unsigned long addr, unsigned long data)
 {
 	long ret = -EIO;

 	switch (request) {
 	default:
 		ret = ptrace_request(child, request, addr, data);
 		break;
 	}

 	return ret;
 }

 /*
  * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
  * {handle,ret_from}_syscall.
  */
 __visible int do_syscall_trace_enter(struct pt_regs *regs)
 {
 	if (test_thread_flag(TIF_SYSCALL_TRACE))
 		if (tracehook_report_syscall_entry(regs))
 			return -1;

 	/*
 	 * Do the secure computing after ptrace; failures should be fast.
 	 * If this fails we might have return value in a0 from seccomp
 	 * (via SECCOMP_RET_ERRNO/TRACE).
 	 */
 	if (secure_computing() == -1)
 		return -1;

 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 		trace_sys_enter(regs, syscall_get_nr(current, regs));
 #endif

 	audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
 	return 0;
 }

 __visible void do_syscall_trace_exit(struct pt_regs *regs)
 {
 	audit_syscall_exit(regs);

 	if (test_thread_flag(TIF_SYSCALL_TRACE))
 		tracehook_report_syscall_exit(regs, 0);

 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 		trace_sys_exit(regs, regs_return_value(regs));
 #endif
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	* Copyright 2015 Regents of the University of California
	* Copyright 2017 SiFive
	*
	* Copied from arch/tile/kernel/ptrace.c
	*/

	#include <asm/ptrace.h>
	#include <asm/syscall.h>
	#include <asm/thread_info.h>
	#include <asm/switch_to.h>
	#include <linux/audit.h>
	#include <linux/ptrace.h>
	#include <linux/elf.h>
	#include <linux/regset.h>
	#include <linux/sched.h>
	#include <linux/sched/task_stack.h>
	#include <linux/tracehook.h>

	#define CREATE_TRACE_POINTS
	#include <trace/events/syscalls.h>

	enum riscv_regset {
	REGSET_X,
	#ifdef CONFIG_FPU
	REGSET_F,
	#endif
	};

	static int riscv_gpr_get(struct task_struct *target,
	const struct user_regset *regset,
	struct membuf to)
	{
	return membuf_write(&to, task_pt_regs(target),
	sizeof(struct user_regs_struct));
	}

	static int riscv_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 ret;
	struct pt_regs *regs;

	regs = task_pt_regs(target);
	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
	return ret;
	}

	#ifdef CONFIG_FPU
	static int riscv_fpr_get(struct task_struct *target,
	const struct user_regset *regset,
	struct membuf to)
	{
	struct __riscv_d_ext_state *fstate = &target->thread.fstate;

	if (target == current)
	fstate_save(current, task_pt_regs(current));

	membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
	membuf_store(&to, fstate->fcsr);
	return membuf_zero(&to, 4); // explicitly pad
	}

	static int riscv_fpr_set(struct task_struct *target,
	const struct user_regset *regset,
	unsigned int pos, unsigned int count,
	const void kbuf, const void __user ubuf)
	{
	int ret;
	struct __riscv_d_ext_state *fstate = &target->thread.fstate;

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
	offsetof(struct __riscv_d_ext_state, fcsr));
	if (!ret) {
	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
	offsetof(struct __riscv_d_ext_state, fcsr) +
	sizeof(fstate->fcsr));
	}

	return ret;
	}
	#endif

	static const struct user_regset riscv_user_regset[] = {
	[REGSET_X] = {
	.core_note_type = NT_PRSTATUS,
	.n = ELF_NGREG,
	.size = sizeof(elf_greg_t),
	.align = sizeof(elf_greg_t),
	.regset_get = riscv_gpr_get,
	.set = riscv_gpr_set,
	},
	#ifdef CONFIG_FPU
	[REGSET_F] = {
	.core_note_type = NT_PRFPREG,
	.n = ELF_NFPREG,
	.size = sizeof(elf_fpreg_t),
	.align = sizeof(elf_fpreg_t),
	.regset_get = riscv_fpr_get,
	.set = riscv_fpr_set,
	},
	#endif
	};

	static const struct user_regset_view riscv_user_native_view = {
	.name = "riscv",
	.e_machine = EM_RISCV,
	.regsets = riscv_user_regset,
	.n = ARRAY_SIZE(riscv_user_regset),
	};

	const struct user_regset_view task_user_regset_view(struct task_struct task)
	{
	return &riscv_user_native_view;
	}

	struct pt_regs_offset {
	const char *name;
	int offset;
	};

	#define REG_OFFSET_NAME(r) {.name = #r, .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(epc),
	REG_OFFSET_NAME(ra),
	REG_OFFSET_NAME(sp),
	REG_OFFSET_NAME(gp),
	REG_OFFSET_NAME(tp),
	REG_OFFSET_NAME(t0),
	REG_OFFSET_NAME(t1),
	REG_OFFSET_NAME(t2),
	REG_OFFSET_NAME(s0),
	REG_OFFSET_NAME(s1),
	REG_OFFSET_NAME(a0),
	REG_OFFSET_NAME(a1),
	REG_OFFSET_NAME(a2),
	REG_OFFSET_NAME(a3),
	REG_OFFSET_NAME(a4),
	REG_OFFSET_NAME(a5),
	REG_OFFSET_NAME(a6),
	REG_OFFSET_NAME(a7),
	REG_OFFSET_NAME(s2),
	REG_OFFSET_NAME(s3),
	REG_OFFSET_NAME(s4),
	REG_OFFSET_NAME(s5),
	REG_OFFSET_NAME(s6),
	REG_OFFSET_NAME(s7),
	REG_OFFSET_NAME(s8),
	REG_OFFSET_NAME(s9),
	REG_OFFSET_NAME(s10),
	REG_OFFSET_NAME(s11),
	REG_OFFSET_NAME(t3),
	REG_OFFSET_NAME(t4),
	REG_OFFSET_NAME(t5),
	REG_OFFSET_NAME(t6),
	REG_OFFSET_NAME(status),
	REG_OFFSET_NAME(badaddr),
	REG_OFFSET_NAME(cause),
	REG_OFFSET_NAME(orig_a0),
	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;
	}

	/**
	* regs_within_kernel_stack() - check the address in the stack
	* @regs: pt_regs which contains kernel stack pointer.
	* @addr: address which is checked.
	*
	* regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
	* If @addr is within the kernel stack, it returns true. If not, returns false.
	*/
	static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
	{
	return (addr & ~(THREAD_SIZE - 1)) ==
	(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
	}

	/**
	* regs_get_kernel_stack_nth() - get Nth entry of the stack
	* @regs: pt_regs which contains kernel stack pointer.
	* @n: stack entry number.
	*
	* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
	* is specified by @regs. If the @n th entry is NOT in the kernel stack,
	* this returns 0.
	*/
	unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
	{
	unsigned long addr = (unsigned long )kernel_stack_pointer(regs);

	addr += n;
	if (regs_within_kernel_stack(regs, (unsigned long)addr))
	return *addr;
	else
	return 0;
	}

	void ptrace_disable(struct task_struct *child)
	{
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	}

	long arch_ptrace(struct task_struct *child, long request,
	unsigned long addr, unsigned long data)
	{
	long ret = -EIO;

	switch (request) {
	default:
	ret = ptrace_request(child, request, addr, data);
	break;
	}

	return ret;
	}

	/*
	* Allows PTRACE_SYSCALL to work. These are called from entry.S in
	* {handle,ret_from}_syscall.
	*/
	__visible int do_syscall_trace_enter(struct pt_regs *regs)
	{
	if (test_thread_flag(TIF_SYSCALL_TRACE))
	if (tracehook_report_syscall_entry(regs))
	return -1;

	/*
	* Do the secure computing after ptrace; failures should be fast.
	* If this fails we might have return value in a0 from seccomp
	* (via SECCOMP_RET_ERRNO/TRACE).
	*/
	if (secure_computing() == -1)
	return -1;

	#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
	trace_sys_enter(regs, syscall_get_nr(current, regs));
	#endif

	audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
	return 0;
	}

	__visible void do_syscall_trace_exit(struct pt_regs *regs)
	{
	audit_syscall_exit(regs);

	if (test_thread_flag(TIF_SYSCALL_TRACE))
	tracehook_report_syscall_exit(regs, 0);

	#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
	trace_sys_exit(regs, regs_return_value(regs));
	#endif
	}