s390: Add pt_regs register and stack access API
This API is needed for the kprobe-based event tracer.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <20100212123840.GB27548@osiris.boeblingen.de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index c802352..2590ce2 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -87,6 +87,7 @@
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_DEFAULT_NO_SPIN_MUTEXES
select HAVE_OPROFILE
select HAVE_KPROBES
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 95dcf18..dd2d913 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -492,13 +492,24 @@
struct task_struct;
extern void user_enable_single_step(struct task_struct *);
extern void user_disable_single_step(struct task_struct *);
+extern void show_regs(struct pt_regs * regs);
#define user_mode(regs) (((regs)->psw.mask & PSW_MASK_PSTATE) != 0)
#define instruction_pointer(regs) ((regs)->psw.addr & PSW_ADDR_INSN)
#define user_stack_pointer(regs)((regs)->gprs[15])
#define regs_return_value(regs)((regs)->gprs[2])
#define profile_pc(regs) instruction_pointer(regs)
-extern void show_regs(struct pt_regs * regs);
+
+int regs_query_register_offset(const char *name);
+const char *regs_query_register_name(unsigned int offset);
+unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset);
+unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n);
+
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+{
+ return regs->gprs[15] & PSW_ADDR_INSN;
+}
+
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 13815d3..1720f38 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -984,3 +984,61 @@
#endif
return &user_s390_view;
}
+
+static const char *gpr_names[NUM_GPRS] = {
+ "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
+ "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
+};
+
+unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
+{
+ if (offset >= NUM_GPRS)
+ return 0;
+ return regs->gprs[offset];
+}
+
+int regs_query_register_offset(const char *name)
+{
+ unsigned long offset;
+
+ if (!name || *name != 'r')
+ return -EINVAL;
+ if (strict_strtoul(name + 1, 10, &offset))
+ return -EINVAL;
+ if (offset >= NUM_GPRS)
+ return -EINVAL;
+ return offset;
+}
+
+const char *regs_query_register_name(unsigned int offset)
+{
+ if (offset >= NUM_GPRS)
+ return NULL;
+ return gpr_names[offset];
+}
+
+static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
+{
+ unsigned long ksp = kernel_stack_pointer(regs);
+
+ return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(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 specifined 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;
+
+ addr = kernel_stack_pointer(regs) + n * sizeof(long);
+ if (!regs_within_kernel_stack(regs, addr))
+ return 0;
+ return *(unsigned long *)addr;
+}