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[PATCH] kprobes: prevent possible race conditions i386 changes

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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
Download Patch File Download Diff File Expand all files Collapse all files

13
arch/i386/kernel/entry.S
View File

@@ -507,7 +507,7 @@ label: \
pushl $__KERNEL_CS; \ pushl $__KERNEL_CS; \
pushl $sysenter_past_esp pushl $sysenter_past_esp
ENTRY(debug) KPROBE_ENTRY(debug)
cmpl $sysenter_entry,(%esp) cmpl $sysenter_entry,(%esp)
jne debug_stack_correct jne debug_stack_correct
FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn) FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
@@ -518,7 +518,7 @@ debug_stack_correct:
movl %esp,%eax # pt_regs pointer movl %esp,%eax # pt_regs pointer
call do_debug call do_debug
jmp ret_from_exception jmp ret_from_exception
.previous .text
/* /*
* NMI is doubly nasty. It can happen _while_ we're handling * NMI is doubly nasty. It can happen _while_ we're handling
* a debug fault, and the debug fault hasn't yet been able to * a debug fault, and the debug fault hasn't yet been able to
@@ -591,13 +591,14 @@ nmi_16bit_stack:
.long 1b,iret_exc .long 1b,iret_exc
.previous .previous
ENTRY(int3) KPROBE_ENTRY(int3)
pushl $-1 # mark this as an int pushl $-1 # mark this as an int
SAVE_ALL SAVE_ALL
xorl %edx,%edx # zero error code xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer movl %esp,%eax # pt_regs pointer
call do_int3 call do_int3
jmp ret_from_exception jmp ret_from_exception
.previous .text
ENTRY(overflow) ENTRY(overflow)
pushl $0 pushl $0
@@ -631,17 +632,19 @@ ENTRY(stack_segment)
pushl $do_stack_segment pushl $do_stack_segment
jmp error_code jmp error_code
ENTRY(general_protection) KPROBE_ENTRY(general_protection)
pushl $do_general_protection pushl $do_general_protection
jmp error_code jmp error_code
.previous .text
ENTRY(alignment_check) ENTRY(alignment_check)
pushl $do_alignment_check pushl $do_alignment_check
jmp error_code jmp error_code
ENTRY(page_fault) KPROBE_ENTRY(page_fault)
pushl $do_page_fault pushl $do_page_fault
jmp error_code jmp error_code
.previous .text
#ifdef CONFIG_X86_MCE #ifdef CONFIG_X86_MCE
ENTRY(machine_check) 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; return 0;
} }
int arch_prepare_kprobe(struct kprobe *p) int __kprobes arch_prepare_kprobe(struct kprobe *p)
{ {
return 0; 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)); memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
p->opcode = *p->addr; p->opcode = *p->addr;
} }
void arch_arm_kprobe(struct kprobe *p) void __kprobes arch_arm_kprobe(struct kprobe *p)
{ {
*p->addr = BREAKPOINT_INSTRUCTION; *p->addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long) p->addr, flush_icache_range((unsigned long) p->addr,
(unsigned long) p->addr + sizeof(kprobe_opcode_t)); (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; *p->addr = p->opcode;
flush_icache_range((unsigned long) p->addr, flush_icache_range((unsigned long) p->addr,
(unsigned long) p->addr + sizeof(kprobe_opcode_t)); (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; 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; unsigned long *sara = (unsigned long *)&regs->esp;
struct kretprobe_instance *ri; 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 * Interrupts are disabled on entry as trap3 is an interrupt gate and they
* remain disabled thorough out this function. * 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; struct kprobe *p;
int ret = 0; int ret = 0;
@@ -259,7 +260,7 @@ no_kprobe:
/* /*
* Called when we hit the probe point at kretprobe_trampoline * 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 kretprobe_instance *ri = NULL;
struct hlist_head *head; 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. * that is atop the stack is the address following the copied instruction.
* We need to make it the address following the original 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 *tos = (unsigned long *)&regs->esp;
unsigned long next_eip = 0; 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. * Wrapper routine to for handling exceptions.
*/ */
int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
void *data) unsigned long val, void *data)
{ {
struct die_args *args = (struct die_args *)data; struct die_args *args = (struct die_args *)data;
switch (val) { switch (val) {
@@ -473,7 +474,7 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
return NOTIFY_DONE; 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); struct jprobe *jp = container_of(p, struct jprobe, kp);
unsigned long addr; unsigned long addr;
@@ -495,7 +496,7 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
return 1; return 1;
} }
void jprobe_return(void) void __kprobes jprobe_return(void)
{ {
preempt_enable_no_resched(); preempt_enable_no_resched();
asm volatile (" xchgl %%ebx,%%esp \n" asm volatile (" xchgl %%ebx,%%esp \n"
@@ -506,7 +507,7 @@ void jprobe_return(void)
(jprobe_saved_esp):"memory"); (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); u8 *addr = (u8 *) (regs->eip - 1);
unsigned long stack_addr = (unsigned long)jprobe_saved_esp; 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); die(str, regs, err);
} }
static void do_trap(int trapnr, int signr, char *str, int vm86, static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
struct pt_regs * regs, long error_code, siginfo_t *info) struct pt_regs * regs, long error_code,
siginfo_t *info)
{ {
struct task_struct *tsk = current; struct task_struct *tsk = current;
tsk->thread.error_code = error_code; 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(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 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(); int cpu = get_cpu();
struct tss_struct *tss = &per_cpu(init_tss, 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); EXPORT_SYMBOL_GPL(unset_nmi_callback);
#ifdef CONFIG_KPROBES #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) if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP) == 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 * find every occurrence of the TF bit that could be saved away even
* by user code) * 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; unsigned int condition;
struct task_struct *tsk = current; struct task_struct *tsk = current;

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

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

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

@@ -21,6 +21,7 @@
#include <linux/vt_kern.h> /* For unblank_screen() */ #include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/highmem.h> #include <linux/highmem.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/kprobes.h>
#include <asm/system.h> #include <asm/system.h>
#include <asm/uaccess.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 1 == 0 means read, 1 means write
* bit 2 == 0 means kernel, 1 means user-mode * 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 task_struct *tsk;
struct mm_struct *mm; struct mm_struct *mm;