RE: [PATCH v10 1/9] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

[平松雅巳 / HIRAMATU，MASAMI]

>From: "David A. Long" <dave.long@xxxxxxxxxx>
>
>Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
>
>Signed-off-by: David A. Long <dave.long@xxxxxxxxxx>

Looks good for me.

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

Thanks,

>---
> arch/arm64/Kconfig              |   1 +
> arch/arm64/include/asm/ptrace.h |  31 +++++++++++
> arch/arm64/kernel/ptrace.c      | 117 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 149 insertions(+)
>
>diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>index 8cc6228..4211b0d 100644
>--- a/arch/arm64/Kconfig
>+++ b/arch/arm64/Kconfig
>@@ -78,6 +78,7 @@ 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 IOMMU_DMA if IOMMU_SUPPORT
>diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
>index e9e5467..7bd6445 100644
>--- a/arch/arm64/include/asm/ptrace.h
>+++ b/arch/arm64/include/asm/ptrace.h
>@@ -118,6 +118,8 @@ struct pt_regs {
> 	u64 syscallno;
> };
>
>+#define MAX_REG_OFFSET offsetof(struct user_pt_regs, pstate)
>+
> #define arch_has_single_step()	(1)
>
> #ifdef CONFIG_COMPAT
>@@ -146,6 +148,35 @@ struct pt_regs {
> #define user_stack_pointer(regs) \
> 	(!compat_user_mode(regs) ? (regs)->sp : (regs)->compat_sp)
>
>+extern int regs_query_register_offset(const char *name);
>+extern const char *regs_query_register_name(unsigned int offset);
>+extern bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr);
>+extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
>+					       unsigned int n);
>+
>+/**
>+ * 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->sp;
>+}
>+
> static inline unsigned long regs_return_value(struct pt_regs *regs)
> {
> 	return regs->regs[0];
>diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
>index ff7f132..efebf0f 100644
>--- a/arch/arm64/kernel/ptrace.c
>+++ b/arch/arm64/kernel/ptrace.c
>@@ -48,6 +48,123 @@
> #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, r)}
>+#define REG_OFFSET_END {.name = NULL, .offset = 0}
>+#define	GPR_OFFSET_NAME(r)	\
>+	{.name = "x" #r, .offset = offsetof(struct pt_regs, regs[r])}
>+
>+static const struct pt_regs_offset regoffset_table[] = {
>+	GPR_OFFSET_NAME(0),
>+	GPR_OFFSET_NAME(1),
>+	GPR_OFFSET_NAME(2),
>+	GPR_OFFSET_NAME(3),
>+	GPR_OFFSET_NAME(4),
>+	GPR_OFFSET_NAME(5),
>+	GPR_OFFSET_NAME(6),
>+	GPR_OFFSET_NAME(7),
>+	GPR_OFFSET_NAME(8),
>+	GPR_OFFSET_NAME(9),
>+	GPR_OFFSET_NAME(10),
>+	GPR_OFFSET_NAME(11),
>+	GPR_OFFSET_NAME(12),
>+	GPR_OFFSET_NAME(13),
>+	GPR_OFFSET_NAME(14),
>+	GPR_OFFSET_NAME(15),
>+	GPR_OFFSET_NAME(16),
>+	GPR_OFFSET_NAME(17),
>+	GPR_OFFSET_NAME(18),
>+	GPR_OFFSET_NAME(19),
>+	GPR_OFFSET_NAME(20),
>+	GPR_OFFSET_NAME(21),
>+	GPR_OFFSET_NAME(22),
>+	GPR_OFFSET_NAME(23),
>+	GPR_OFFSET_NAME(24),
>+	GPR_OFFSET_NAME(25),
>+	GPR_OFFSET_NAME(26),
>+	GPR_OFFSET_NAME(27),
>+	GPR_OFFSET_NAME(28),
>+	GPR_OFFSET_NAME(29),
>+	GPR_OFFSET_NAME(30),
>+	{.name = "lr", .offset = offsetof(struct pt_regs, regs[30])},
>+	REG_OFFSET_NAME(sp),
>+	REG_OFFSET_NAME(pc),
>+	REG_OFFSET_NAME(pstate),
>+	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.
>--
>2.5.0
>
>
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