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Commit 05e14cb3 authored by Prasanna S Panchamukhi's avatar Prasanna S Panchamukhi Committed by Linus Torvalds
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[PATCH] Kprobes: prevent possible race conditions sparc64 changes 



This patch contains the sparc64 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 1f7ad57b

arch/sparc64/kernel/kprobes.c

+20 −16
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/kprobes.h>

#include <asm/kdebug.h>

#include <asm/signal.h>

#include <asm/cacheflush.h>



/* We do not have hardware single-stepping on sparc64.

 * So we implement software single-stepping with breakpoint
@@ -37,31 +38,31 @@ 
 * - Mark that we are no longer actively in a kprobe.

 */



int arch_prepare_kprobe(struct kprobe *p)

int __kprobes arch_prepare_kprobe(struct kprobe *p)

{

	return 0;

}



void arch_copy_kprobe(struct kprobe *p)

void __kprobes arch_copy_kprobe(struct kprobe *p)

{

	p->ainsn.insn[0] = *p->addr;

	p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;

	p->opcode = *p->addr;

}



void arch_arm_kprobe(struct kprobe *p)

void __kprobes arch_arm_kprobe(struct kprobe *p)

{

	*p->addr = BREAKPOINT_INSTRUCTION;

	flushi(p->addr);

}



void arch_disarm_kprobe(struct kprobe *p)

void __kprobes arch_disarm_kprobe(struct kprobe *p)

{

	*p->addr = p->opcode;

	flushi(p->addr);

}



void arch_remove_kprobe(struct kprobe *p)

void __kprobes arch_remove_kprobe(struct kprobe *p)

{

}
@@ -111,7 +112,7 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) 
	}

}



static int kprobe_handler(struct pt_regs *regs)

static int __kprobes kprobe_handler(struct pt_regs *regs)

{

	struct kprobe *p;

	void *addr = (void *) regs->tpc;
@@ -191,8 +192,9 @@ static int kprobe_handler(struct pt_regs *regs) 
 * The original INSN location was REAL_PC, it actually

 * executed at PC and produced destination address NPC.

 */

static unsigned long relbranch_fixup(u32 insn, unsigned long real_pc,

				     unsigned long pc, unsigned long npc)

static unsigned long __kprobes relbranch_fixup(u32 insn, unsigned long real_pc,

					       unsigned long pc,

					       unsigned long npc)

{

	/* Branch not taken, no mods necessary.  */

	if (npc == pc + 0x4UL)
@@ -217,7 +219,8 @@ static unsigned long relbranch_fixup(u32 insn, unsigned long real_pc, 
/* If INSN is an instruction which writes it's PC location

 * into a destination register, fix that up.

 */

static void retpc_fixup(struct pt_regs *regs, u32 insn, unsigned long real_pc)

static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,

				  unsigned long real_pc)

{

	unsigned long *slot = NULL;
@@ -257,7 +260,7 @@ static void retpc_fixup(struct pt_regs *regs, u32 insn, unsigned long real_pc) 
 * This function prepares to return from the post-single-step

 * breakpoint trap.

 */

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

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

{

	u32 insn = p->ainsn.insn[0];
@@ -315,8 +318,8 @@ 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;

	switch (val) {
@@ -344,7 +347,8 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, 
	return NOTIFY_DONE;

}



asmlinkage void kprobe_trap(unsigned long trap_level, struct pt_regs *regs)

asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,

				      struct pt_regs *regs)

{

	BUG_ON(trap_level != 0x170 && trap_level != 0x171);
@@ -368,7 +372,7 @@ static struct pt_regs jprobe_saved_regs; 
static struct pt_regs *jprobe_saved_regs_location;

static struct sparc_stackf jprobe_saved_stack;



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);
@@ -390,7 +394,7 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) 
	return 1;

}



void jprobe_return(void)

void __kprobes jprobe_return(void)

{

	preempt_enable_no_resched();

	__asm__ __volatile__(
@@ -403,7 +407,7 @@ extern void jprobe_return_trap_instruction(void); 


extern void __show_regs(struct pt_regs * regs);



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

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

{

	u32 *addr = (u32 *) regs->tpc;

arch/sparc64/kernel/vmlinux.lds.S

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ SECTIONS 
    *(.text)

    SCHED_TEXT

    LOCK_TEXT

    KPROBES_TEXT

    *(.gnu.warning)

  } =0

  _etext = .;

arch/sparc64/mm/fault.c

+5 −3
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/smp_lock.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/kprobes.h>



#include <asm/page.h>

#include <asm/pgtable.h>
@@ -117,7 +118,8 @@ unsigned long __init prom_probe_memory (void) 
	return tally;

}



static void unhandled_fault(unsigned long address, struct task_struct *tsk,

static void __kprobes unhandled_fault(unsigned long address,

				      struct task_struct *tsk,

				      struct pt_regs *regs)

{

	if ((unsigned long) address < PAGE_SIZE) {
@@ -304,7 +306,7 @@ static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code, 
	unhandled_fault (address, current, regs);

}



asmlinkage void do_sparc64_fault(struct pt_regs *regs)

asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)

{

	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma;

arch/sparc64/mm/init.c

+2 −1
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/pagemap.h>

#include <linux/fs.h>

#include <linux/seq_file.h>

#include <linux/kprobes.h>



#include <asm/head.h>

#include <asm/system.h>
@@ -250,7 +251,7 @@ void flush_dcache_page(struct page *page) 
	put_cpu();

}



void flush_icache_range(unsigned long start, unsigned long end)

void __kprobes flush_icache_range(unsigned long start, unsigned long end)

{

	/* Cheetah has coherent I-cache. */

	if (tlb_type == spitfire) {

arch/sparc64/mm/ultra.S

+2 −0
Original line number Diff line number Diff line
@@ -119,6 +119,7 @@ __spitfire_flush_tlb_mm_slow: 
#else

#error unsupported PAGE_SIZE

#endif

	.section .kprobes.text

	.align		32

	.globl		__flush_icache_page

__flush_icache_page:	/* %o0 = phys_page */
@@ -201,6 +202,7 @@ dflush4:stxa %g0, [%o4] ASI_DCACHE_TAG 
	 nop

#endif /* DCACHE_ALIASING_POSSIBLE */



	.previous .text

	.align		32

__prefill_dtlb:

	rdpr		%pstate, %g7