MIPS: Add uprobes support.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index ffc3203..f6fc6aa 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -14,11 +14,16 @@
 #include <linux/linkage.h>
 #include <linux/types.h>
 #include <asm/isadep.h>
+#include <asm/page.h>
+#include <asm/thread_info.h>
 #include <uapi/asm/ptrace.h>
 
 /*
  * This struct defines the way the registers are stored on the stack during a
  * system call/exception. As usual the registers k0/k1 aren't being saved.
+ *
+ * If you add a register here, also add it to regoffset_table[] in
+ * arch/mips/kernel/ptrace.c.
  */
 struct pt_regs {
 #ifdef CONFIG_32BIT
@@ -43,8 +48,83 @@ struct pt_regs {
 	unsigned long long mpl[6];        /* MTM{0-5} */
 	unsigned long long mtp[6];        /* MTP{0-5} */
 #endif
+	unsigned long __last[0];
 } __aligned(8);
 
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+{
+	return regs->regs[31];
+}
+
+/*
+ * Don't use asm-generic/ptrace.h it defines FP accessors that don't make
+ * sense on MIPS.  We rather want an error if they get invoked.
+ */
+
+static inline void instruction_pointer_set(struct pt_regs *regs,
+                                           unsigned long val)
+{
+	regs->cp0_epc = val;
+}
+
+/* Query offset/name of register from its name/offset */
+extern int regs_query_register_offset(const char *name);
+#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last))
+
+/**
+ * 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. The @offset is the
+ * offset of the register in struct pt_regs address which specified by @regs.
+ * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
+ */
+static inline unsigned long regs_get_register(struct pt_regs *regs,
+                                              unsigned int offset)
+{
+	if (unlikely(offset > MAX_REG_OFFSET))
+		return 0;
+
+	return *(unsigned long *)((unsigned long)regs + offset);
+}
+
+/**
+ * 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 inline int 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.
+ */
+static inline 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;
+}
+
 struct task_struct;
 
 extern int ptrace_getregs(struct task_struct *child,