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[PATCH] kprobes: prevent possible race conditions i386 changes 

This patch contains the i386 architecture specific changes to prevent the
possible race conditions.

Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Prasanna S Panchamukhi 2005-09-06 15:19:27 -07:00 committed by Linus Torvalds
parent d0aaff9796
commit 3d97ae5b95
5 changed files with 34 additions and 25 deletions
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13
arch/i386/kernel/entry.S
View File

@ -507,7 +507,7 @@ label: \
pushl $__KERNEL_CS; \
pushl $sysenter_past_esp
ENTRY(debug)
KPROBE_ENTRY(debug)
cmpl $sysenter_entry,(%esp)
jne debug_stack_correct
FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
@ -518,7 +518,7 @@ debug_stack_correct:
movl %esp,%eax # pt_regs pointer
call do_debug
jmp ret_from_exception
.previous .text
/*
* NMI is doubly nasty. It can happen _while_ we're handling
* a debug fault, and the debug fault hasn't yet been able to
@ -591,13 +591,14 @@ nmi_16bit_stack:
.long 1b,iret_exc
.previous
ENTRY(int3)
KPROBE_ENTRY(int3)
pushl $-1 # mark this as an int
SAVE_ALL
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_int3
jmp ret_from_exception
.previous .text
ENTRY(overflow)
pushl $0
@ -631,17 +632,19 @@ ENTRY(stack_segment)
pushl $do_stack_segment
jmp error_code
ENTRY(general_protection)
KPROBE_ENTRY(general_protection)
pushl $do_general_protection
jmp error_code
.previous .text
ENTRY(alignment_check)
pushl $do_alignment_check
jmp error_code
ENTRY(page_fault)
KPROBE_ENTRY(page_fault)
pushl $do_page_fault
jmp error_code
.previous .text
#ifdef CONFIG_X86_MCE
ENTRY(machine_check)

29
arch/i386/kernel/kprobes.c
View File

@ -62,32 +62,32 @@ static inline int is_IF_modifier(kprobe_opcode_t opcode)
return 0;
}
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)
{
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)
{
}
@ -127,7 +127,8 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
regs->eip = (unsigned long)&p->ainsn.insn;
}
void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs)
void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
struct pt_regs *regs)
{
unsigned long *sara = (unsigned long *)&regs->esp;
struct kretprobe_instance *ri;
@ -150,7 +151,7 @@ void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs)
* Interrupts are disabled on entry as trap3 is an interrupt gate and they
* remain disabled thorough out this function.
*/
static int kprobe_handler(struct pt_regs *regs)
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
@ -259,7 +260,7 @@ no_kprobe:
/*
* Called when we hit the probe point at kretprobe_trampoline
*/
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;
@ -338,7 +339,7 @@ int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
* that is atop the stack is the address following the copied instruction.
* We need to make it the address following the original instruction.
*/
static void resume_execution(struct kprobe *p, struct pt_regs *regs)
static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
{
unsigned long *tos = (unsigned long *)&regs->esp;
unsigned long next_eip = 0;
@ -444,8 +445,8 @@ 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) {
@ -473,7 +474,7 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
return NOTIFY_DONE;
}
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);
unsigned long addr;
@ -495,7 +496,7 @@ 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 (" xchgl %%ebx,%%esp \n"
@ -506,7 +507,7 @@ void jprobe_return(void)
(jprobe_saved_esp):"memory");
}
int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
u8 *addr = (u8 *) (regs->eip - 1);
unsigned long stack_addr = (unsigned long)jprobe_saved_esp;

12
arch/i386/kernel/traps.c
View File

@ -363,8 +363,9 @@ static inline void die_if_kernel(const char * str, struct pt_regs * regs, long e
die(str, regs, err);
}
static void do_trap(int trapnr, int signr, char *str, int vm86,
struct pt_regs * regs, long error_code, siginfo_t *info)
static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
struct pt_regs * regs, long error_code,
siginfo_t *info)
{
struct task_struct *tsk = current;
tsk->thread.error_code = error_code;
@ -460,7 +461,8 @@ DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0)
fastcall void do_general_protection(struct pt_regs * regs, long error_code)
fastcall void __kprobes do_general_protection(struct pt_regs * regs,
long error_code)
{
int cpu = get_cpu();
struct tss_struct *tss = &per_cpu(init_tss, cpu);
@ -676,7 +678,7 @@ void unset_nmi_callback(void)
EXPORT_SYMBOL_GPL(unset_nmi_callback);
#ifdef CONFIG_KPROBES
fastcall void do_int3(struct pt_regs *regs, long error_code)
fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
{
if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
@ -710,7 +712,7 @@ fastcall void do_int3(struct pt_regs *regs, long error_code)
* find every occurrence of the TF bit that could be saved away even
* by user code)
*/
fastcall void do_debug(struct pt_regs * regs, long error_code)
fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)
{
unsigned int condition;
struct task_struct *tsk = current;

1
arch/i386/kernel/vmlinux.lds.S
View File

@ -22,6 +22,7 @@ SECTIONS
*(.text)
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
*(.fixup)
*(.gnu.warning)
} = 0x9090

4
arch/i386/mm/fault.c
View File

@ -21,6 +21,7 @@
#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@ -223,7 +224,8 @@ fastcall void do_invalid_op(struct pt_regs *, unsigned long);
* bit 1 == 0 means read, 1 means write
* bit 2 == 0 means kernel, 1 means user-mode
*/
fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code)
fastcall void __kprobes do_page_fault(struct pt_regs *regs,
unsigned long error_code)
{
struct task_struct *tsk;
struct mm_struct *mm;