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Commit bb144a85 authored by Prasanna S Panchamukhi's avatar Prasanna S Panchamukhi Committed by Linus Torvalds
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[PATCH] Kprobes: prevent possible race conditions ppc64 changes 



This patch contains the ppc64 architecture specific changes to prevent the
possible race conditions.

Signed-off-by: default avatarPrasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0f2fbdcb

arch/ppc64/kernel/kprobes.c

+15 −14
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ static struct kprobe *kprobe_prev; 
static unsigned long kprobe_status_prev, kprobe_saved_msr_prev;

static struct pt_regs jprobe_saved_regs;



int arch_prepare_kprobe(struct kprobe *p)

int __kprobes arch_prepare_kprobe(struct kprobe *p)

{

	int ret = 0;

	kprobe_opcode_t insn = *p->addr;
@@ -68,27 +68,27 @@ int arch_prepare_kprobe(struct kprobe *p) 
	return ret;

}



void arch_copy_kprobe(struct kprobe *p)

void __kprobes arch_copy_kprobe(struct kprobe *p)

{

	memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));

	p->opcode = *p->addr;

}



void arch_arm_kprobe(struct kprobe *p)

void __kprobes arch_arm_kprobe(struct kprobe *p)

{

	*p->addr = BREAKPOINT_INSTRUCTION;

	flush_icache_range((unsigned long) p->addr,

			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));

}



void arch_disarm_kprobe(struct kprobe *p)

void __kprobes arch_disarm_kprobe(struct kprobe *p)

{

	*p->addr = p->opcode;

	flush_icache_range((unsigned long) p->addr,

			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));

}



void arch_remove_kprobe(struct kprobe *p)

void __kprobes arch_remove_kprobe(struct kprobe *p)

{

	up(&kprobe_mutex);

	free_insn_slot(p->ainsn.insn);
@@ -122,7 +122,8 @@ static inline void restore_previous_kprobe(void) 
	kprobe_saved_msr = kprobe_saved_msr_prev;

}



void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs)

void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,

				      struct pt_regs *regs)

{

	struct kretprobe_instance *ri;
@@ -244,7 +245,7 @@ void kretprobe_trampoline_holder(void) 
/*

 * Called when the probe at kretprobe trampoline is hit

 */

int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)

int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)

{

        struct kretprobe_instance *ri = NULL;

        struct hlist_head *head;
@@ -308,7 +309,7 @@ int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 
 * single-stepped a copy of the instruction.  The address of this

 * copy is p->ainsn.insn.

 */

static void resume_execution(struct kprobe *p, struct pt_regs *regs)

static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)

{

	int ret;

	unsigned int insn = *p->ainsn.insn;
@@ -373,8 +374,8 @@ static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 
/*

 * Wrapper routine to for handling exceptions.

 */

int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,

			     void *data)

int __kprobes kprobe_exceptions_notify(struct notifier_block *self,

				       unsigned long val, void *data)

{

	struct die_args *args = (struct die_args *)data;

	int ret = NOTIFY_DONE;
@@ -406,7 +407,7 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, 
	return ret;

}



int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)

int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)

{

	struct jprobe *jp = container_of(p, struct jprobe, kp);
@@ -419,16 +420,16 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) 
	return 1;

}



void jprobe_return(void)

void __kprobes jprobe_return(void)

{

	asm volatile("trap" ::: "memory");

}



void jprobe_return_end(void)

void __kprobes jprobe_return_end(void)

{

};



int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)

int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)

{

	/*

	 * FIXME - we should ideally be validating that we got here 'cos

arch/ppc64/kernel/misc.S

+2 −2
Original line number Diff line number Diff line
@@ -183,7 +183,7 @@ PPC64_CACHES: 
 *   flush all bytes from start through stop-1 inclusive

 */



_GLOBAL(__flush_icache_range)

_KPROBE(__flush_icache_range)



/*

 * Flush the data cache to memory
@@ -223,7 +223,7 @@ _GLOBAL(__flush_icache_range) 
	bdnz	2b

	isync

	blr

	

	.previous .text

/*

 * Like above, but only do the D-cache.

 *

arch/ppc64/kernel/traps.c

+3 −2
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/init.h>

#include <linux/module.h>

#include <linux/delay.h>

#include <linux/kprobes.h>

#include <asm/kdebug.h>



#include <asm/pgtable.h>
@@ -220,7 +221,7 @@ void instruction_breakpoint_exception(struct pt_regs *regs) 
	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);

}



void single_step_exception(struct pt_regs *regs)

void __kprobes single_step_exception(struct pt_regs *regs)

{

	regs->msr &= ~MSR_SE;  /* Turn off 'trace' bit */
@@ -398,7 +399,7 @@ check_bug_trap(struct pt_regs *regs) 
	return 0;

}



void program_check_exception(struct pt_regs *regs)

void __kprobes program_check_exception(struct pt_regs *regs)

{

	if (debugger_fault_handler(regs))

		return;

arch/ppc64/kernel/vmlinux.lds.S

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ SECTIONS 
	*(.text .text.*)

	SCHED_TEXT

	LOCK_TEXT

	KPROBES_TEXT

	*(.fixup)

	. = ALIGN(4096);

	_etext = .;

arch/ppc64/mm/fault.c

+3 −2
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/interrupt.h>

#include <linux/smp_lock.h>

#include <linux/module.h>

#include <linux/kprobes.h>



#include <asm/page.h>

#include <asm/pgtable.h>
@@ -84,7 +85,7 @@ static int store_updates_sp(struct pt_regs *regs) 
 * The return value is 0 if the fault was handled, or the signal

 * number if this is a kernel fault that can't be handled here.

 */

int do_page_fault(struct pt_regs *regs, unsigned long address,

int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,

			    unsigned long error_code)

{

	struct vm_area_struct * vma;