[PATCH] Kprobes IA64: arch_prepare_kprobes() cleanup
arch_prepare_kprobes() was doing lots of functionality
in just one single function. This patch
attempts to clean up arch_prepare_kprobes() by moving
specific sub task to the following (new)functions
1)valid_kprobe_addr() -->> validate the given kprobe address
2)get_kprobe_inst(slot..)->> Retrives the instruction for a given slot from the bundle
3)prepare_break_inst() -->> Prepares break instruction within the bundle
3a)update_kprobe_inst_flag()-->>Updates the internal flags, required
for proper emulation of the instruction at later
point in time.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 98bef04..5d53446 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -81,90 +81,141 @@
{ u, u, u }, /* 1F */
};
-int arch_prepare_kprobe(struct kprobe *p)
+/*
+ * In this function we check to see if the instruction
+ * is IP relative instruction and update the kprobe
+ * inst flag accordingly
+ */
+static void update_kprobe_inst_flag(uint template, uint slot, uint major_opcode,
+ unsigned long kprobe_inst, struct kprobe *p)
{
- unsigned long addr = (unsigned long) p->addr;
- unsigned long *bundle_addr = (unsigned long *)(addr & ~0xFULL);
- unsigned long slot = addr & 0xf;
- unsigned long template;
- unsigned long major_opcode = 0;
- unsigned long lx_type_inst = 0;
- unsigned long kprobe_inst = 0;
- bundle_t *bundle = &p->ainsn.insn.bundle;
-
- memcpy(&p->opcode.bundle, bundle_addr, sizeof(bundle_t));
- memcpy(&p->ainsn.insn.bundle, bundle_addr, sizeof(bundle_t));
-
p->ainsn.inst_flag = 0;
p->ainsn.target_br_reg = 0;
- template = bundle->quad0.template;
+ if (bundle_encoding[template][slot] == B) {
+ switch (major_opcode) {
+ case INDIRECT_CALL_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+ p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+ break;
+ case IP_RELATIVE_PREDICT_OPCODE:
+ case IP_RELATIVE_BRANCH_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
+ break;
+ case IP_RELATIVE_CALL_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
+ p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+ p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+ break;
+ }
+ } else if (bundle_encoding[template][slot] == X) {
+ switch (major_opcode) {
+ case LONG_CALL_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+ p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+ break;
+ }
+ }
+ return;
+}
- if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) {
+/*
+ * In this function we override the bundle with
+ * the break instruction at the given slot.
+ */
+static void prepare_break_inst(uint template, uint slot, uint major_opcode,
+ unsigned long kprobe_inst, struct kprobe *p)
+{
+ unsigned long break_inst = BREAK_INST;
+ bundle_t *bundle = &p->ainsn.insn.bundle;
+
+ /*
+ * Copy the original kprobe_inst qualifying predicate(qp)
+ * to the break instruction
+ */
+ break_inst |= (0x3f & kprobe_inst);
+
+ switch (slot) {
+ case 0:
+ bundle->quad0.slot0 = break_inst;
+ break;
+ case 1:
+ bundle->quad0.slot1_p0 = break_inst;
+ bundle->quad1.slot1_p1 = break_inst >> (64-46);
+ break;
+ case 2:
+ bundle->quad1.slot2 = break_inst;
+ break;
+ }
+
+ /*
+ * Update the instruction flag, so that we can
+ * emulate the instruction properly after we
+ * single step on original instruction
+ */
+ update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
+}
+
+static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
+ unsigned long *kprobe_inst, uint *major_opcode)
+{
+ unsigned long kprobe_inst_p0, kprobe_inst_p1;
+ unsigned int template;
+
+ template = bundle->quad0.template;
+
+ switch (slot) {
+ case 0:
+ *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
+ *kprobe_inst = bundle->quad0.slot0;
+ break;
+ case 1:
+ *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
+ kprobe_inst_p0 = bundle->quad0.slot1_p0;
+ kprobe_inst_p1 = bundle->quad1.slot1_p1;
+ *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
+ break;
+ case 2:
+ *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
+ *kprobe_inst = bundle->quad1.slot2;
+ break;
+ }
+}
+
+static int valid_kprobe_addr(int template, int slot, unsigned long addr)
+{
+ if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
addr);
return -EINVAL;
}
+ return 0;
+}
- if (slot == 1 && bundle_encoding[template][1] == L) {
- lx_type_inst = 1;
- slot = 2;
- }
+int arch_prepare_kprobe(struct kprobe *p)
+{
+ unsigned long addr = (unsigned long) p->addr;
+ unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
+ unsigned long kprobe_inst=0;
+ unsigned int slot = addr & 0xf, template, major_opcode = 0;
+ bundle_t *bundle = &p->ainsn.insn.bundle;
- switch (slot) {
- case 0:
- major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
- kprobe_inst = bundle->quad0.slot0;
- bundle->quad0.slot0 = BREAK_INST | (0x3f & kprobe_inst);
- break;
- case 1:
- major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
- kprobe_inst = (bundle->quad0.slot1_p0 |
- (bundle->quad1.slot1_p1 << (64-46)));
- bundle->quad0.slot1_p0 = BREAK_INST | (0x3f & kprobe_inst);
- bundle->quad1.slot1_p1 = (BREAK_INST >> (64-46));
- break;
- case 2:
- major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
- kprobe_inst = bundle->quad1.slot2;
- bundle->quad1.slot2 = BREAK_INST | (0x3f & kprobe_inst);
- break;
- }
+ memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
+ memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));
- /*
- * Look for IP relative Branches, IP relative call or
- * IP relative predicate instructions
- */
- if (bundle_encoding[template][slot] == B) {
- switch (major_opcode) {
- case INDIRECT_CALL_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
- p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
- break;
- case IP_RELATIVE_PREDICT_OPCODE:
- case IP_RELATIVE_BRANCH_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
- break;
- case IP_RELATIVE_CALL_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
- p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
- p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
- break;
- default:
- /* Do nothing */
- break;
- }
- } else if (lx_type_inst) {
- switch (major_opcode) {
- case LONG_CALL_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
- p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
- break;
- default:
- /* Do nothing */
- break;
- }
- }
+ template = bundle->quad0.template;
+
+ if(valid_kprobe_addr(template, slot, addr))
+ return -EINVAL;
+
+ /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
+ if (slot == 1 && bundle_encoding[template][1] == L)
+ slot++;
+
+ /* Get kprobe_inst and major_opcode from the bundle */
+ get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
+
+ prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
return 0;
}
@@ -260,7 +311,7 @@
if (regs->cr_iip == bundle_addr) {
regs->cr_iip = resume_addr;
}
- }
+ }
turn_ss_off:
/* Turn off Single Step bit */