diff mbox

[v4,1/6] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

Message ID 1420949002-3726-2-git-send-email-dave.long@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

David Long Jan. 11, 2015, 4:03 a.m. UTC
From: "David A. Long" <dave.long@linaro.org>

Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.

Signed-off-by: David A. Long <dave.long@linaro.org>
---
 arch/arm64/Kconfig                   |   1 +
 arch/arm64/include/asm/ptrace.h      |  29 +++++++++
 arch/arm64/include/uapi/asm/ptrace.h |  36 +++++++++++
 arch/arm64/kernel/ptrace.c           | 119 +++++++++++++++++++++++++++++++++++
 4 files changed, 185 insertions(+)

Comments

Steve Capper Jan. 12, 2015, 12:51 p.m. UTC | #1
On Sat, Jan 10, 2015 at 11:03:16PM -0500, David Long wrote:
> From: "David A. Long" <dave.long@linaro.org>
> 
> Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
> 
> Signed-off-by: David A. Long <dave.long@linaro.org>
> ---
>  arch/arm64/Kconfig                   |   1 +
>  arch/arm64/include/asm/ptrace.h      |  29 +++++++++
>  arch/arm64/include/uapi/asm/ptrace.h |  36 +++++++++++
>  arch/arm64/kernel/ptrace.c           | 119 +++++++++++++++++++++++++++++++++++
>  4 files changed, 185 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index b1f9a20..12b3fd6 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -64,6 +64,7 @@ config ARM64
>  	select HAVE_PERF_EVENTS
>  	select HAVE_PERF_REGS
>  	select HAVE_PERF_USER_STACK_DUMP
> +	select HAVE_REGS_AND_STACK_ACCESS_API
>  	select HAVE_RCU_TABLE_FREE
>  	select HAVE_SYSCALL_TRACEPOINTS
>  	select IRQ_DOMAIN
> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> index 41ed9e1..3613e49 100644
> --- a/arch/arm64/include/asm/ptrace.h
> +++ b/arch/arm64/include/asm/ptrace.h
> @@ -111,6 +111,8 @@ struct pt_regs {
>  	u64 syscallno;
>  };
>  
> +#define MAX_REG_OFFSET (sizeof(struct user_pt_regs) - sizeof(u64))
> +
>  #define arch_has_single_step()	(1)
>  
>  #ifdef CONFIG_COMPAT
> @@ -139,11 +141,38 @@ struct pt_regs {
>  #define user_stack_pointer(regs) \
>  	(!compat_user_mode(regs) ? (regs)->sp : (regs)->compat_sp)
>  
> +/**
> + * regs_get_register() - get register value from its offset
> + * @regs:	   pt_regs from which register value is gotten
> + * @offset:    offset number of the register.
> + *
> + * regs_get_register returns the value of a register whose offset from @regs.
> + * The @offset is the offset of the register in struct pt_regs.
> + * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
> + */
> +static inline u64 regs_get_register(struct pt_regs *regs,
> +					      unsigned int offset)
> +{
> +	if (unlikely(offset > MAX_REG_OFFSET))
> +		return 0;
> +	return *(u64 *)((u64)regs + offset);
> +}
> +
> +/* Valid only for Kernel mode traps. */
> +static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
> +{
> +	return regs->ARM_sp;
> +}
> +
>  static inline unsigned long regs_return_value(struct pt_regs *regs)
>  {
>  	return regs->regs[0];
>  }
>  
> +extern int regs_query_register_offset(const char *name);
> +extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
> +					       unsigned int n);
> +
>  /*
>   * Are the current registers suitable for user mode? (used to maintain
>   * security in signal handlers)
> diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
> index 6913643..700d28b 100644
> --- a/arch/arm64/include/uapi/asm/ptrace.h
> +++ b/arch/arm64/include/uapi/asm/ptrace.h
> @@ -61,6 +61,42 @@
>  
>  #ifndef __ASSEMBLY__
>  
> +#define ARM_cpsr	pstate
> +#define ARM_pc		pc
> +#define ARM_sp		sp
> +#define ARM_lr		regs[30]
> +#define ARM_fp		regs[29]
> +#define ARM_x28		regs[28]
> +#define ARM_x27		regs[27]
> +#define ARM_x26		regs[26]
> +#define ARM_x25		regs[25]
> +#define ARM_x24		regs[24]
> +#define ARM_x23		regs[23]
> +#define ARM_x22		regs[22]
> +#define ARM_x21		regs[21]
> +#define ARM_x20		regs[20]
> +#define ARM_x19		regs[19]
> +#define ARM_x18		regs[18]
> +#define ARM_ip1		regs[17]
> +#define ARM_ip0		regs[16]
> +#define ARM_x15		regs[15]
> +#define ARM_x14		regs[14]
> +#define ARM_x13		regs[13]
> +#define ARM_x12		regs[12]
> +#define ARM_x11		regs[11]
> +#define ARM_x10		regs[10]
> +#define ARM_x9		regs[9]
> +#define ARM_x8		regs[8]
> +#define ARM_x7		regs[7]
> +#define ARM_x6		regs[6]
> +#define ARM_x5		regs[5]
> +#define ARM_x4		regs[4]
> +#define ARM_x3		regs[3]
> +#define ARM_x2		regs[2]
> +#define ARM_x1		regs[1]
> +#define ARM_x0		regs[0]
> +#define ARM_ORIG_x0	orig_x0
> +
>  /*
>   * User structures for general purpose, floating point and debug registers.
>   */
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index d882b83..9115b25 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -48,6 +48,125 @@
>  #define CREATE_TRACE_POINTS
>  #include <trace/events/syscalls.h>
>  
> +struct pt_regs_offset {
> +	const char *name;
> +	int offset;
> +};
> +
> +#define REG_OFFSET_NAME(r) \
> +	{.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
> +#define REG_OFFSET_END {.name = NULL, .offset = 0}
> +
> +static const struct pt_regs_offset regoffset_table[] = {
> +	REG_OFFSET_NAME(x0),
> +	REG_OFFSET_NAME(x1),
> +	REG_OFFSET_NAME(x2),
> +	REG_OFFSET_NAME(x3),
> +	REG_OFFSET_NAME(x4),
> +	REG_OFFSET_NAME(x5),
> +	REG_OFFSET_NAME(x6),
> +	REG_OFFSET_NAME(x7),
> +	REG_OFFSET_NAME(x8),
> +	REG_OFFSET_NAME(x9),
> +	REG_OFFSET_NAME(x10),
> +	REG_OFFSET_NAME(x11),
> +	REG_OFFSET_NAME(x12),
> +	REG_OFFSET_NAME(x13),
> +	REG_OFFSET_NAME(x14),
> +	REG_OFFSET_NAME(x15),
> +	REG_OFFSET_NAME(ip0),
> +	REG_OFFSET_NAME(ip1),
> +	REG_OFFSET_NAME(x18),
> +	REG_OFFSET_NAME(x19),
> +	REG_OFFSET_NAME(x20),
> +	REG_OFFSET_NAME(x21),
> +	REG_OFFSET_NAME(x22),
> +	REG_OFFSET_NAME(x23),
> +	REG_OFFSET_NAME(x24),
> +	REG_OFFSET_NAME(x25),
> +	REG_OFFSET_NAME(x26),
> +	REG_OFFSET_NAME(x27),
> +	REG_OFFSET_NAME(x28),
> +	REG_OFFSET_NAME(fp),
> +	REG_OFFSET_NAME(lr),
> +/*
> +	REG_OFFSET_NAME(ip),
> +*/

Should this comment block be removed?

> +	REG_OFFSET_NAME(sp),
> +	REG_OFFSET_NAME(pc),
> +	REG_OFFSET_NAME(cpsr),
> +	REG_OFFSET_NAME(ORIG_x0),
> +	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_query_register_name() - query register name from its offset
> + * @offset:	the offset of a register in struct pt_regs.
> + *
> + * regs_query_register_name() returns the name of a register from its
> + * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
> + */
> +const char *regs_query_register_name(unsigned int offset)
> +{
> +	const struct pt_regs_offset *roff;
> +
> +	for (roff = regoffset_table; roff->name != NULL; roff++)
> +		if (roff->offset == offset)
> +			return roff->name;
> +	return NULL;
> +}
> +
> +/**
> + * 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.
> + */
> +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;
> +}
> +
>  /*
>   * TODO: does not yet catch signals sent when the child dies.
>   * in exit.c or in signal.c.
> -- 
> 1.8.1.2
>
Masami Hiramatsu Jan. 15, 2015, 7:07 a.m. UTC | #2
(2015/01/12 21:51), Steve Capper wrote:
> On Sat, Jan 10, 2015 at 11:03:16PM -0500, David Long wrote:
>> From: "David A. Long" <dave.long@linaro.org>
>>
>> Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
>>
>> Signed-off-by: David A. Long <dave.long@linaro.org>
>> ---
>>  arch/arm64/Kconfig                   |   1 +
>>  arch/arm64/include/asm/ptrace.h      |  29 +++++++++
>>  arch/arm64/include/uapi/asm/ptrace.h |  36 +++++++++++
>>  arch/arm64/kernel/ptrace.c           | 119 +++++++++++++++++++++++++++++++++++
>>  4 files changed, 185 insertions(+)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index b1f9a20..12b3fd6 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -64,6 +64,7 @@ config ARM64
>>  	select HAVE_PERF_EVENTS
>>  	select HAVE_PERF_REGS
>>  	select HAVE_PERF_USER_STACK_DUMP
>> +	select HAVE_REGS_AND_STACK_ACCESS_API
>>  	select HAVE_RCU_TABLE_FREE
>>  	select HAVE_SYSCALL_TRACEPOINTS
>>  	select IRQ_DOMAIN
>> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
>> index 41ed9e1..3613e49 100644
>> --- a/arch/arm64/include/asm/ptrace.h
>> +++ b/arch/arm64/include/asm/ptrace.h
>> @@ -111,6 +111,8 @@ struct pt_regs {
>>  	u64 syscallno;
>>  };
>>  
>> +#define MAX_REG_OFFSET (sizeof(struct user_pt_regs) - sizeof(u64))
>> +
>>  #define arch_has_single_step()	(1)
>>  
>>  #ifdef CONFIG_COMPAT
>> @@ -139,11 +141,38 @@ struct pt_regs {
>>  #define user_stack_pointer(regs) \
>>  	(!compat_user_mode(regs) ? (regs)->sp : (regs)->compat_sp)
>>  
>> +/**
>> + * regs_get_register() - get register value from its offset
>> + * @regs:	   pt_regs from which register value is gotten
>> + * @offset:    offset number of the register.
>> + *
>> + * regs_get_register returns the value of a register whose offset from @regs.
>> + * The @offset is the offset of the register in struct pt_regs.
>> + * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
>> + */
>> +static inline u64 regs_get_register(struct pt_regs *regs,
>> +					      unsigned int offset)
>> +{
>> +	if (unlikely(offset > MAX_REG_OFFSET))
>> +		return 0;
>> +	return *(u64 *)((u64)regs + offset);
>> +}
>> +
>> +/* Valid only for Kernel mode traps. */
>> +static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
>> +{
>> +	return regs->ARM_sp;
>> +}
>> +
>>  static inline unsigned long regs_return_value(struct pt_regs *regs)
>>  {
>>  	return regs->regs[0];
>>  }
>>  
>> +extern int regs_query_register_offset(const char *name);
>> +extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
>> +					       unsigned int n);
>> +
>>  /*
>>   * Are the current registers suitable for user mode? (used to maintain
>>   * security in signal handlers)
>> diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
>> index 6913643..700d28b 100644
>> --- a/arch/arm64/include/uapi/asm/ptrace.h
>> +++ b/arch/arm64/include/uapi/asm/ptrace.h
>> @@ -61,6 +61,42 @@
>>  
>>  #ifndef __ASSEMBLY__
>>  
>> +#define ARM_cpsr	pstate
>> +#define ARM_pc		pc
>> +#define ARM_sp		sp
>> +#define ARM_lr		regs[30]
>> +#define ARM_fp		regs[29]
>> +#define ARM_x28		regs[28]
>> +#define ARM_x27		regs[27]
>> +#define ARM_x26		regs[26]
>> +#define ARM_x25		regs[25]
>> +#define ARM_x24		regs[24]
>> +#define ARM_x23		regs[23]
>> +#define ARM_x22		regs[22]
>> +#define ARM_x21		regs[21]
>> +#define ARM_x20		regs[20]
>> +#define ARM_x19		regs[19]
>> +#define ARM_x18		regs[18]
>> +#define ARM_ip1		regs[17]
>> +#define ARM_ip0		regs[16]
>> +#define ARM_x15		regs[15]
>> +#define ARM_x14		regs[14]
>> +#define ARM_x13		regs[13]
>> +#define ARM_x12		regs[12]
>> +#define ARM_x11		regs[11]
>> +#define ARM_x10		regs[10]
>> +#define ARM_x9		regs[9]
>> +#define ARM_x8		regs[8]
>> +#define ARM_x7		regs[7]
>> +#define ARM_x6		regs[6]
>> +#define ARM_x5		regs[5]
>> +#define ARM_x4		regs[4]
>> +#define ARM_x3		regs[3]
>> +#define ARM_x2		regs[2]
>> +#define ARM_x1		regs[1]
>> +#define ARM_x0		regs[0]
>> +#define ARM_ORIG_x0	orig_x0
>> +
>>  /*
>>   * User structures for general purpose, floating point and debug registers.
>>   */
>> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
>> index d882b83..9115b25 100644
>> --- a/arch/arm64/kernel/ptrace.c
>> +++ b/arch/arm64/kernel/ptrace.c
>> @@ -48,6 +48,125 @@
>>  #define CREATE_TRACE_POINTS
>>  #include <trace/events/syscalls.h>
>>  
>> +struct pt_regs_offset {
>> +	const char *name;
>> +	int offset;
>> +};
>> +
>> +#define REG_OFFSET_NAME(r) \
>> +	{.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
>> +#define REG_OFFSET_END {.name = NULL, .offset = 0}
>> +
>> +static const struct pt_regs_offset regoffset_table[] = {
>> +	REG_OFFSET_NAME(x0),
>> +	REG_OFFSET_NAME(x1),
>> +	REG_OFFSET_NAME(x2),
>> +	REG_OFFSET_NAME(x3),
>> +	REG_OFFSET_NAME(x4),
>> +	REG_OFFSET_NAME(x5),
>> +	REG_OFFSET_NAME(x6),
>> +	REG_OFFSET_NAME(x7),
>> +	REG_OFFSET_NAME(x8),
>> +	REG_OFFSET_NAME(x9),
>> +	REG_OFFSET_NAME(x10),
>> +	REG_OFFSET_NAME(x11),
>> +	REG_OFFSET_NAME(x12),
>> +	REG_OFFSET_NAME(x13),
>> +	REG_OFFSET_NAME(x14),
>> +	REG_OFFSET_NAME(x15),
>> +	REG_OFFSET_NAME(ip0),
>> +	REG_OFFSET_NAME(ip1),
>> +	REG_OFFSET_NAME(x18),
>> +	REG_OFFSET_NAME(x19),
>> +	REG_OFFSET_NAME(x20),
>> +	REG_OFFSET_NAME(x21),
>> +	REG_OFFSET_NAME(x22),
>> +	REG_OFFSET_NAME(x23),
>> +	REG_OFFSET_NAME(x24),
>> +	REG_OFFSET_NAME(x25),
>> +	REG_OFFSET_NAME(x26),
>> +	REG_OFFSET_NAME(x27),
>> +	REG_OFFSET_NAME(x28),
>> +	REG_OFFSET_NAME(fp),
>> +	REG_OFFSET_NAME(lr),
>> +/*
>> +	REG_OFFSET_NAME(ip),
>> +*/
> 
> Should this comment block be removed?

Agreed, I think it should be removed.
Except that, this looks good to me.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks!

> 
>> +	REG_OFFSET_NAME(sp),
>> +	REG_OFFSET_NAME(pc),
>> +	REG_OFFSET_NAME(cpsr),
>> +	REG_OFFSET_NAME(ORIG_x0),
>> +	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_query_register_name() - query register name from its offset
>> + * @offset:	the offset of a register in struct pt_regs.
>> + *
>> + * regs_query_register_name() returns the name of a register from its
>> + * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
>> + */
>> +const char *regs_query_register_name(unsigned int offset)
>> +{
>> +	const struct pt_regs_offset *roff;
>> +
>> +	for (roff = regoffset_table; roff->name != NULL; roff++)
>> +		if (roff->offset == offset)
>> +			return roff->name;
>> +	return NULL;
>> +}
>> +
>> +/**
>> + * 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.
>> + */
>> +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;
>> +}
>> +
>>  /*
>>   * TODO: does not yet catch signals sent when the child dies.
>>   * in exit.c or in signal.c.
>> -- 
>> 1.8.1.2
>>
>
diff mbox

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1f9a20..12b3fd6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -64,6 +64,7 @@  config ARM64
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RCU_TABLE_FREE
 	select HAVE_SYSCALL_TRACEPOINTS
 	select IRQ_DOMAIN
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 41ed9e1..3613e49 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -111,6 +111,8 @@  struct pt_regs {
 	u64 syscallno;
 };
 
+#define MAX_REG_OFFSET (sizeof(struct user_pt_regs) - sizeof(u64))
+
 #define arch_has_single_step()	(1)
 
 #ifdef CONFIG_COMPAT
@@ -139,11 +141,38 @@  struct pt_regs {
 #define user_stack_pointer(regs) \
 	(!compat_user_mode(regs) ? (regs)->sp : (regs)->compat_sp)
 
+/**
+ * regs_get_register() - get register value from its offset
+ * @regs:	   pt_regs from which register value is gotten
+ * @offset:    offset number of the register.
+ *
+ * regs_get_register returns the value of a register whose offset from @regs.
+ * The @offset is the offset of the register in struct pt_regs.
+ * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
+ */
+static inline u64 regs_get_register(struct pt_regs *regs,
+					      unsigned int offset)
+{
+	if (unlikely(offset > MAX_REG_OFFSET))
+		return 0;
+	return *(u64 *)((u64)regs + offset);
+}
+
+/* Valid only for Kernel mode traps. */
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+{
+	return regs->ARM_sp;
+}
+
 static inline unsigned long regs_return_value(struct pt_regs *regs)
 {
 	return regs->regs[0];
 }
 
+extern int regs_query_register_offset(const char *name);
+extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
+					       unsigned int n);
+
 /*
  * Are the current registers suitable for user mode? (used to maintain
  * security in signal handlers)
diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
index 6913643..700d28b 100644
--- a/arch/arm64/include/uapi/asm/ptrace.h
+++ b/arch/arm64/include/uapi/asm/ptrace.h
@@ -61,6 +61,42 @@ 
 
 #ifndef __ASSEMBLY__
 
+#define ARM_cpsr	pstate
+#define ARM_pc		pc
+#define ARM_sp		sp
+#define ARM_lr		regs[30]
+#define ARM_fp		regs[29]
+#define ARM_x28		regs[28]
+#define ARM_x27		regs[27]
+#define ARM_x26		regs[26]
+#define ARM_x25		regs[25]
+#define ARM_x24		regs[24]
+#define ARM_x23		regs[23]
+#define ARM_x22		regs[22]
+#define ARM_x21		regs[21]
+#define ARM_x20		regs[20]
+#define ARM_x19		regs[19]
+#define ARM_x18		regs[18]
+#define ARM_ip1		regs[17]
+#define ARM_ip0		regs[16]
+#define ARM_x15		regs[15]
+#define ARM_x14		regs[14]
+#define ARM_x13		regs[13]
+#define ARM_x12		regs[12]
+#define ARM_x11		regs[11]
+#define ARM_x10		regs[10]
+#define ARM_x9		regs[9]
+#define ARM_x8		regs[8]
+#define ARM_x7		regs[7]
+#define ARM_x6		regs[6]
+#define ARM_x5		regs[5]
+#define ARM_x4		regs[4]
+#define ARM_x3		regs[3]
+#define ARM_x2		regs[2]
+#define ARM_x1		regs[1]
+#define ARM_x0		regs[0]
+#define ARM_ORIG_x0	orig_x0
+
 /*
  * User structures for general purpose, floating point and debug registers.
  */
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index d882b83..9115b25 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -48,6 +48,125 @@ 
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
 
+struct pt_regs_offset {
+	const char *name;
+	int offset;
+};
+
+#define REG_OFFSET_NAME(r) \
+	{.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+	REG_OFFSET_NAME(x0),
+	REG_OFFSET_NAME(x1),
+	REG_OFFSET_NAME(x2),
+	REG_OFFSET_NAME(x3),
+	REG_OFFSET_NAME(x4),
+	REG_OFFSET_NAME(x5),
+	REG_OFFSET_NAME(x6),
+	REG_OFFSET_NAME(x7),
+	REG_OFFSET_NAME(x8),
+	REG_OFFSET_NAME(x9),
+	REG_OFFSET_NAME(x10),
+	REG_OFFSET_NAME(x11),
+	REG_OFFSET_NAME(x12),
+	REG_OFFSET_NAME(x13),
+	REG_OFFSET_NAME(x14),
+	REG_OFFSET_NAME(x15),
+	REG_OFFSET_NAME(ip0),
+	REG_OFFSET_NAME(ip1),
+	REG_OFFSET_NAME(x18),
+	REG_OFFSET_NAME(x19),
+	REG_OFFSET_NAME(x20),
+	REG_OFFSET_NAME(x21),
+	REG_OFFSET_NAME(x22),
+	REG_OFFSET_NAME(x23),
+	REG_OFFSET_NAME(x24),
+	REG_OFFSET_NAME(x25),
+	REG_OFFSET_NAME(x26),
+	REG_OFFSET_NAME(x27),
+	REG_OFFSET_NAME(x28),
+	REG_OFFSET_NAME(fp),
+	REG_OFFSET_NAME(lr),
+/*
+	REG_OFFSET_NAME(ip),
+*/
+	REG_OFFSET_NAME(sp),
+	REG_OFFSET_NAME(pc),
+	REG_OFFSET_NAME(cpsr),
+	REG_OFFSET_NAME(ORIG_x0),
+	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_query_register_name() - query register name from its offset
+ * @offset:	the offset of a register in struct pt_regs.
+ *
+ * regs_query_register_name() returns the name of a register from its
+ * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
+ */
+const char *regs_query_register_name(unsigned int offset)
+{
+	const struct pt_regs_offset *roff;
+
+	for (roff = regoffset_table; roff->name != NULL; roff++)
+		if (roff->offset == offset)
+			return roff->name;
+	return NULL;
+}
+
+/**
+ * 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.
+ */
+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;
+}
+
 /*
  * TODO: does not yet catch signals sent when the child dies.
  * in exit.c or in signal.c.