From: "David A. Long" <dave.l...@linaro.org>

Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.

Signed-off-by: David A. Long <dave.l...@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 02f31b7..bc9b516 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -58,6 +58,7 @@ 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 HAVE_KPROBES if !XIP_KERNEL
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index d3e782a..24cc048 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 (offsetof(struct pt_regs, orig_x0))
+
 #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 8a4ae8e..36a94c8 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -47,6 +47,125 @@
 #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.
-- 
1.8.1.2

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