arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64, including supporting
functions and defines.

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: Remove unused functions]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 51622ba..d3c0c23 100644 (file)
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -121,7 +121,6 @@ extern unsigned long profile_pc(struct pt_regs *regs);
 #define MAX_REG_OFFSET (offsetof(struct pt_regs, ARM_ORIG_r0))
 
 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);

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5a0a691..fab133c 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -85,6 +85,7 @@ 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 a307eb6..941e12d 100644 (file)
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -74,6 +74,7 @@
 #define COMPAT_PT_DATA_ADDR            0x10004
 #define COMPAT_PT_TEXT_END_ADDR                0x10008
 #ifndef __ASSEMBLY__
+#include <linux/bug.h>
 
 /* sizeof(struct user) for AArch32 */
 #define COMPAT_USER_SZ 296
@@ -119,6 +120,8 @@ struct pt_regs {
        u64 syscallno;
 };
 
+#define MAX_REG_OFFSET offsetof(struct pt_regs, pstate)
+
 #define arch_has_single_step() (1)
 
 #ifdef CONFIG_COMPAT
@@ -147,6 +150,53 @@ 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 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 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)
+{
+       u64 val = 0;
+
+       WARN_ON(offset & 7);
+
+       offset >>= 3;
+       switch (offset) {
+       case 0 ... 30:
+               val = regs->regs[offset];
+               break;
+       case offsetof(struct pt_regs, sp) >> 3:
+               val = regs->sp;
+               break;
+       case offsetof(struct pt_regs, pc) >> 3:
+               val = regs->pc;
+               break;
+       case offsetof(struct pt_regs, pstate) >> 3:
+               val = regs->pstate;
+               break;
+       default:
+               val = 0;
+       }
+
+       return val;
+}
+
+/* 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 3f6cd5c..030c1d5 100644 (file)
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -48,6 +48,107 @@
 #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_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.
+ */
+static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
+{
+       return ((addr & ~(THREAD_SIZE - 1))  ==
+               (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
+               on_irq_stack(addr, raw_smp_processor_id());
+}
+
+/**
+ * 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.