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Commit 5f8efbb9 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] x86_64: Allow nesting of int3 by default for kprobes 



This unbreaks recursive kprobes which didn't work anymore
due to an earlier patch which converted the debug entry point
to use an IST.

This also allows nesting of the debug entry point too.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent aa41eb99

arch/x86_64/kernel/asm-offsets.c

+2 −3
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ int main(void) 
	ENTRY(irqcount);

	ENTRY(cpunumber);

	ENTRY(irqstackptr);

	ENTRY(data_offset);

	BLANK();

#undef ENTRY

#ifdef CONFIG_IA32_EMULATION
@@ -66,8 +67,6 @@ int main(void) 
	DEFINE(pbe_orig_address, offsetof(struct pbe, orig_address));

	DEFINE(pbe_next, offsetof(struct pbe, next));

	BLANK();

#if DEBUG_STKSZ > EXCEPTION_STKSZ

	DEFINE(DEBUG_IST, DEBUG_STACK);

#endif

	DEFINE(TSS_ist, offsetof(struct tss_struct, ist));

	return 0;

}

arch/x86_64/kernel/entry.S

+5 −7
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <asm/unistd.h>

#include <asm/thread_info.h>

#include <asm/hw_irq.h>

#include <asm/page.h>



	.code64
@@ -674,9 +675,6 @@ ENTRY(spurious_interrupt) 


	/* error code is on the stack already */

	/* handle NMI like exceptions that can happen everywhere */

#ifndef DEBUG_IST

# define DEBUG_IST 0

#endif

	.macro paranoidentry sym, ist=0

	SAVE_ALL

	cld
@@ -695,11 +693,11 @@ ENTRY(spurious_interrupt) 
	movq ORIG_RAX(%rsp),%rsi

	movq $-1,ORIG_RAX(%rsp)

	.if \ist

	subq	$EXCEPTION_STACK_SIZE, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)

	subq	$EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)

	.endif

	call \sym

	.if \ist

	addq	$EXCEPTION_STACK_SIZE, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)

	addq	$EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)

	.endif

	cli

	.endm
@@ -918,7 +916,7 @@ KPROBE_ENTRY(debug) 
 	INTR_FRAME

	pushq $0

	CFI_ADJUST_CFA_OFFSET 8		

	paranoidentry do_debug, DEBUG_IST

	paranoidentry do_debug, DEBUG_STACK

	jmp paranoid_exit

	CFI_ENDPROC

	.previous .text
@@ -976,7 +974,7 @@ KPROBE_ENTRY(int3) 
 	INTR_FRAME

 	pushq $0

 	CFI_ADJUST_CFA_OFFSET 8

 	paranoidentry do_int3, DEBUG_IST

 	paranoidentry do_int3, DEBUG_STACK

 	jmp paranoid_exit

 	CFI_ENDPROC

	.previous .text

include/asm-x86_64/page.h

+7 −0
Original line number Diff line number Diff line
@@ -26,6 +26,13 @@ 
#define IRQSTACK_ORDER 2

#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER)



#define STACKFAULT_STACK 1

#define DOUBLEFAULT_STACK 2

#define NMI_STACK 3

#define DEBUG_STACK 4

#define MCE_STACK 5

#define N_EXCEPTION_STACKS 5  /* hw limit: 7 */



#define LARGE_PAGE_MASK (~(LARGE_PAGE_SIZE-1))

#define LARGE_PAGE_SIZE (1UL << PMD_SHIFT)

include/asm-x86_64/processor.h

+0 −7
Original line number Diff line number Diff line
@@ -273,13 +273,6 @@ struct thread_struct { 
#define INIT_MMAP \

{ &init_mm, 0, 0, NULL, PAGE_SHARED, VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }



#define STACKFAULT_STACK 1

#define DOUBLEFAULT_STACK 2 

#define NMI_STACK 3 

#define DEBUG_STACK 4 

#define MCE_STACK 5

#define N_EXCEPTION_STACKS 5  /* hw limit: 7 */



#define start_thread(regs,new_rip,new_rsp) do { \

	asm volatile("movl %0,%%fs; movl %0,%%es; movl %0,%%ds": :"r" (0));	 \

	load_gs_index(0);							\