The following 2.6.12-rc5-mm1 patch is a cleanup of the ia64 kprobes
implementation such that all of the bundle manipulation logic is
concentrated in arch_prepare_kprobe().
With the current design for kprobes, the arch specific code only
has a chance to return failure inside the arch_prepare_kprobe()
function.
This patch moves all of the work that was happening in arch_copy_kprobe()
and most of the work that was happening in arch_arm_kprobe() into
arch_prepare_kprobe(). By doing this we can add further robustness checks
in arch_arm_kprobe() and refuse to insert kprobes that will cause problems.
--rusty
signed-off-by: Rusty Lynch <[email protected]>
Signed-off-by: Anil S Keshavamurthy <[email protected]>
arch/ia64/kernel/kprobes.c | 178 +++++++++++++++++++--------------------------
include/asm-ia64/kprobes.h | 7 +
2 files changed, 84 insertions(+), 101 deletions(-)
Index: linux-2.6.12-rc5/arch/ia64/kernel/kprobes.c
===================================================================
--- linux-2.6.12-rc5.orig/arch/ia64/kernel/kprobes.c
+++ linux-2.6.12-rc5/arch/ia64/kernel/kprobes.c
@@ -84,121 +84,97 @@ static enum instruction_type bundle_enco
int arch_prepare_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long) p->addr;
- unsigned long bundle_addr = addr & ~0xFULL;
+ unsigned long *bundle_addr = (unsigned long *)(addr & ~0xFULL);
unsigned long slot = addr & 0xf;
- bundle_t bundle;
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;
- /*
- * TODO: Verify that a probe is not being inserted
- * in sensitive regions of code
- * TODO: Verify that the memory holding the probe is rwx
- * TODO: verify this is a kernel address
- */
- memcpy(&bundle, (unsigned long *)bundle_addr, sizeof(bundle_t));
- template = bundle.quad0.template;
- if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) {
- printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n", addr);
- return -EINVAL;
- }
- return 0;
-}
+ memcpy(&p->opcode.bundle, bundle_addr, sizeof(bundle_t));
+ memcpy(&p->ainsn.insn.bundle, bundle_addr, sizeof(bundle_t));
-void arch_copy_kprobe(struct kprobe *p)
-{
- unsigned long addr = (unsigned long)p->addr;
- unsigned long bundle_addr = addr & ~0xFULL;
+ p->ainsn.inst_flag = 0;
+ p->ainsn.target_br_reg = 0;
- memcpy(&p->ainsn.insn.bundle, (unsigned long *)bundle_addr,
- sizeof(bundle_t));
- memcpy(&p->opcode.bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));
-}
+ template = bundle->quad0.template;
-void arch_arm_kprobe(struct kprobe *p)
-{
- unsigned long addr = (unsigned long)p->addr;
- unsigned long arm_addr = 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.inst_flag = 0;
- p->ainsn.target_br_reg = 0;
-
- memcpy(&bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));
- template = bundle.quad0.template;
- if (slot == 1 && bundle_encoding[template][1] == L) {
- lx_type_inst = 1;
- slot = 2;
- }
+ if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) {
+ printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
+ addr);
+ return -EINVAL;
+ }
+ if (slot == 1 && bundle_encoding[template][1] == L) {
+ lx_type_inst = 1;
+ slot = 2;
+ }
switch (slot) {
case 0:
- major_opcode = (bundle.quad0.slot0 >> SLOT0_OPCODE_SHIFT);
- kprobe_inst = bundle.quad0.slot0;
- bundle.quad0.slot0 = BREAK_INST;
+ major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
+ kprobe_inst = bundle->quad0.slot0;
+ bundle->quad0.slot0 = BREAK_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;
- bundle.quad1.slot1_p1 = (BREAK_INST >> (64-46));
+ 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;
+ 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;
+ major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
+ kprobe_inst = bundle->quad1.slot2;
+ bundle->quad1.slot2 = BREAK_INST;
break;
}
- /*
- * 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;
- }
- }
-
- /* Flush icache for the instruction at the emulated address */
- flush_icache_range((unsigned long)&p->ainsn.insn.bundle,
- (unsigned long)&p->ainsn.insn.bundle +
- sizeof(bundle_t));
- /*
- * Patch the original instruction with the probe instruction
- * and flush the instruction cache
- */
- memcpy((char *) arm_addr, (char *) &bundle, 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;
+ }
+ }
+
+ return 0;
+}
+
+void arch_arm_kprobe(struct kprobe *p)
+{
+ unsigned long addr = (unsigned long)p->addr;
+ unsigned long arm_addr = addr & ~0xFULL;
+
+ memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
}
@@ -226,7 +202,7 @@ void arch_remove_kprobe(struct kprobe *p
*/
static void resume_execution(struct kprobe *p, struct pt_regs *regs)
{
- unsigned long bundle_addr = ((unsigned long) (&p->ainsn.insn.bundle)) & ~0xFULL;
+ unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
unsigned long template;
int slot = ((unsigned long)p->addr & 0xf);
@@ -293,7 +269,7 @@ turn_ss_off:
static void prepare_ss(struct kprobe *p, struct pt_regs *regs)
{
- unsigned long bundle_addr = (unsigned long) &p->ainsn.insn.bundle;
+ unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
unsigned long slot = (unsigned long)p->addr & 0xf;
/* Update instruction pointer (IIP) and slot number (IPSR.ri) */
Index: linux-2.6.12-rc5/include/asm-ia64/kprobes.h
===================================================================
--- linux-2.6.12-rc5.orig/include/asm-ia64/kprobes.h
+++ linux-2.6.12-rc5/include/asm-ia64/kprobes.h
@@ -30,6 +30,8 @@
#define BREAK_INST (long)(__IA64_BREAK_KPROBE << 6)
+struct kprobe;
+
typedef struct _bundle {
struct {
unsigned long long template : 5;
@@ -79,6 +81,11 @@ static inline void jprobe_return(void)
{
}
+/* ia64 does not need this */
+static inline void arch_copy_kprobe(struct kprobe *p)
+{
+}
+
#ifdef CONFIG_KPROBES
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
-
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