Commit 8bc76772 authored by Rusty Lynch's avatar Rusty Lynch Committed by Linus Torvalds
Browse files

[PATCH] Kprobes ia64 cleanup 



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: default avatarRusty Lynch <Rusty.lynch@intel.com>
Signed-off-by: default avatarAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent cd2675bf

arch/ia64/kernel/kprobes.c

+77 −101
Original line number Diff line number Diff line
@@ -84,77 +84,53 @@ 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 slot = addr & 0xf;

	bundle_t bundle;

	unsigned long template;



	/*

	 * 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;

}



void arch_copy_kprobe(struct kprobe *p)

{

	unsigned long addr = (unsigned long)p->addr;

	unsigned long bundle_addr = addr & ~0xFULL;



	memcpy(&p->ainsn.insn.bundle, (unsigned long *)bundle_addr,

				sizeof(bundle_t));

	memcpy(&p->opcode.bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));

}



void arch_arm_kprobe(struct kprobe *p)

{

	unsigned long addr = (unsigned long)p->addr;

	unsigned long arm_addr = addr & ~0xFULL;

	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;

	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;



	memcpy(&bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));

    	template = bundle.quad0.template;

 	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;

	}



 	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
@@ -190,15 +166,15 @@ void arch_arm_kprobe(struct kprobe *p) 
 		}

	}



 	/* 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));

	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) */

include/asm-ia64/kprobes.h

+7 −0
Original line number Diff line number Diff line
@@ -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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