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[PATCH] Kprobes ia64 cleanup
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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.

Signed-off-by: Rusty Lynch <Rusty.lynch@intel.com>
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>
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Rusty Lynch authored and Linus Torvalds committed Jun 23, 2005
1 parent cd2675b commit 8bc7677
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Showing 2 changed files with 84 additions and 101 deletions.
178 changes: 77 additions & 101 deletions arch/ia64/kernel/kprobes.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -84,121 +84,97 @@ static enum instruction_type bundle_encoding[32][3] = {
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));
}

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -293,7 +269,7 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs)

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) */
Expand Down
7 changes: 7 additions & 0 deletions include/asm-ia64/kprobes.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,8 @@

#define BREAK_INST (long)(__IA64_BREAK_KPROBE << 6)

struct kprobe;

typedef struct _bundle {
struct {
unsigned long long template : 5;
Expand Down Expand Up @@ -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);
Expand Down

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