[PATCH] Kprobes/IA64: architecture specific JProbes support

This patch adds IA64 architecture specific JProbes support on top of Kprobes

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Rusty Lynch <Rusty.lynch@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 22 insertions, 6 deletions

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 81a53f99a573..6683a44f419f 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -35,12 +35,15 @@
 #include <asm/pgtable.h>
 #include <asm/kdebug.h>
 
+extern void jprobe_inst_return(void);
+
 /* kprobe_status settings */
 #define KPROBE_HIT_ACTIVE       0x00000001
 #define KPROBE_HIT_SS           0x00000002
 
 static struct kprobe *current_kprobe;
 static unsigned long kprobe_status;
+static struct pt_regs jprobe_saved_regs;
 
 enum instruction_type {A, I, M, F, B, L, X, u};
 static enum instruction_type bundle_encoding[32][3] = {
@@ -318,15 +321,28 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
 
 int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 {
-        printk(KERN_WARNING "Jprobes is not supported\n");
-        return 0;
-}
+        struct jprobe *jp = container_of(p, struct jprobe, kp);
+        unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
 
-void jprobe_return(void)
-{
+        /* save architectural state */
+        jprobe_saved_regs = *regs;
+
+        /* after rfi, execute the jprobe instrumented function */
+        regs->cr_iip = addr & ~0xFULL;
+        ia64_psr(regs)->ri = addr & 0xf;
+        regs->r1 = ((struct fnptr *)(jp->entry))->gp;
+
+        /*
+         * fix the return address to our jprobe_inst_return() function
+         * in the jprobes.S file
+         */
+        regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
+
+        return 1;
 }
 
 int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 {
-        return 0;
+        *regs = jprobe_saved_regs;
+        return 1;
 }