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Subject[PATCH v6 1/6] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature
Date
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(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1b8e973..987a681 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -65,6 +65,7 @@ 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 d6dd9fd..655620e 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 (sizeof(struct user_pt_regs) - sizeof(u64))
+
#define arch_has_single_step() (1)

#ifdef CONFIG_COMPAT
@@ -146,11 +148,38 @@ 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..58c0223 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_pstate 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..a889f79 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(pstate),
+ 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


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