diff mbox

[v5,1/6] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

Message ID 1424214701-4899-2-git-send-email-dave.long@linaro.org
State New
Headers show

Commit Message

David Long Feb. 17, 2015, 11:11 p.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           | 116 +++++++++++++++++++++++++++++++++++
 4 files changed, 182 insertions(+)

Comments

David Long April 20, 2015, 7:15 a.m. UTC | #1
On 03/25/15 09:44, Catalin Marinas wrote:
> On Tue, Feb 17, 2015 at 06:11:36PM -0500, David Long wrote:
>> 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
>
> There is no CPSR on AArch64, it's just called PSTATE. But more
> importantly, what's the point of all these macros?
>
>> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
>> index d882b83..adc1f39 100644
>> --- a/arch/arm64/kernel/ptrace.c
>> +++ b/arch/arm64/kernel/ptrace.c
>> @@ -48,6 +48,122 @@
>>   #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),
>
> If it is just for defining a name, just change the REG_OFFSET_NAME macro
> to take a string argument and remove all the ARM_ macros.
>
> I'm also not sure why we need the ARM_ prefix. Do you see them used
> outside the arm64 context?
>

Sorry Catalin, I don't have a record of having replied to this yet so 
this is a quite late reply.

The macros were taken from the 32-bit ARM implementation, which in turn 
looks to be taken from x86/sh/powerpc for 
HAVE_REGS_AND_STACK_ACCESS_API.  I've replaced the hacky define of cpsr 
with pstate. The macros create symbolic names that can be looked up by, 
for example, event tracing strings entered through debugfs.  This is 
consistent across multiple platforms.

-dl

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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..adc1f39 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -48,6 +48,122 @@ 
 #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(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.