parisc: Add HAVE_REGS_AND_STACK_ACCESS_API feature

Some parts of the HAVE_REGS_AND_STACK_ACCESS_API feature is needed for
the rseq syscall. This patch adds the most important parts, and as long
as we don't support kprobes, we should be fine.

Signed-off-by: Helge Deller <deller@gmx.de>

arch/parisc/Kconfig

@@ -45,6 +45,7 @@ config PARISC
 	select HAVE_ARCH_HASH
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_REGS_AND_STACK_ACCESS_API
 	select GENERIC_SCHED_CLOCK
 	select HAVE_UNSTABLE_SCHED_CLOCK if SMP
 	select GENERIC_CLOCKEVENTS

arch/parisc/include/asm/ptrace.h

@@ -25,4 +25,15 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
 	return regs->gr[20];
 }
 
+static inline void instruction_pointer_set(struct pt_regs *regs,
+						unsigned long val)
+{
+        regs->iaoq[0] = val;
+}
+
+/* Query offset/name of register from its name/offset */
+extern int regs_query_register_offset(const char *name);
+extern const char *regs_query_register_name(unsigned int offset);
+#define MAX_REG_OFFSET (offsetof(struct pt_regs, ipsw))
+
 #endif

arch/parisc/kernel/ptrace.c

@@ -676,3 +676,103 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 #endif
 	return &user_parisc_native_view;
 }
+
+
+/* HAVE_REGS_AND_STACK_ACCESS_API feature */
+
+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_INDEX(r,i) {.name = #r#i, .offset = offsetof(struct pt_regs, r[i])}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+	REG_OFFSET_INDEX(gr,0),
+	REG_OFFSET_INDEX(gr,1),
+	REG_OFFSET_INDEX(gr,2),
+	REG_OFFSET_INDEX(gr,3),
+	REG_OFFSET_INDEX(gr,4),
+	REG_OFFSET_INDEX(gr,5),
+	REG_OFFSET_INDEX(gr,6),
+	REG_OFFSET_INDEX(gr,7),
+	REG_OFFSET_INDEX(gr,8),
+	REG_OFFSET_INDEX(gr,9),
+	REG_OFFSET_INDEX(gr,10),
+	REG_OFFSET_INDEX(gr,11),
+	REG_OFFSET_INDEX(gr,12),
+	REG_OFFSET_INDEX(gr,13),
+	REG_OFFSET_INDEX(gr,14),
+	REG_OFFSET_INDEX(gr,15),
+	REG_OFFSET_INDEX(gr,16),
+	REG_OFFSET_INDEX(gr,17),
+	REG_OFFSET_INDEX(gr,18),
+	REG_OFFSET_INDEX(gr,19),
+	REG_OFFSET_INDEX(gr,20),
+	REG_OFFSET_INDEX(gr,21),
+	REG_OFFSET_INDEX(gr,22),
+	REG_OFFSET_INDEX(gr,23),
+	REG_OFFSET_INDEX(gr,24),
+	REG_OFFSET_INDEX(gr,25),
+	REG_OFFSET_INDEX(gr,26),
+	REG_OFFSET_INDEX(gr,27),
+	REG_OFFSET_INDEX(gr,28),
+	REG_OFFSET_INDEX(gr,29),
+	REG_OFFSET_INDEX(gr,30),
+	REG_OFFSET_INDEX(gr,31),
+	REG_OFFSET_INDEX(sr,0),
+	REG_OFFSET_INDEX(sr,1),
+	REG_OFFSET_INDEX(sr,2),
+	REG_OFFSET_INDEX(sr,3),
+	REG_OFFSET_INDEX(sr,4),
+	REG_OFFSET_INDEX(sr,5),
+	REG_OFFSET_INDEX(sr,6),
+	REG_OFFSET_INDEX(sr,7),
+	REG_OFFSET_INDEX(iasq,0),
+	REG_OFFSET_INDEX(iasq,1),
+	REG_OFFSET_INDEX(iaoq,0),
+	REG_OFFSET_INDEX(iaoq,1),
+	REG_OFFSET_NAME(cr27),
+	REG_OFFSET_NAME(ksp),
+	REG_OFFSET_NAME(kpc),
+	REG_OFFSET_NAME(sar),
+	REG_OFFSET_NAME(iir),
+	REG_OFFSET_NAME(isr),
+	REG_OFFSET_NAME(ior),
+	REG_OFFSET_NAME(ipsw),
+	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;
+}