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tile: support kprobes on tilegx

This change includes support for Kprobes, Jprobes and Return Probes.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Tony Lu <zlu@tilera.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
master
Tony Lu 8 years ago
committed by Chris Metcalf
parent
commit
3fa17c395b
  1. 2
      arch/tile/Kconfig
  2. 1
      arch/tile/include/asm/Kbuild
  3. 28
      arch/tile/include/asm/kdebug.h
  4. 79
      arch/tile/include/asm/kprobes.h
  5. 1
      arch/tile/include/asm/ptrace.h
  6. 1
      arch/tile/include/uapi/arch/opcode_tilegx.h
  7. 1
      arch/tile/include/uapi/arch/opcode_tilepro.h
  8. 1
      arch/tile/kernel/Makefile
  9. 528
      arch/tile/kernel/kprobes.c
  10. 14
      arch/tile/kernel/smp.c
  11. 45
      arch/tile/kernel/traps.c
  12. 1
      arch/tile/kernel/vmlinux.lds.S
  13. 12
      arch/tile/mm/fault.c
  14. 9
      samples/kprobes/kprobe_example.c

2
arch/tile/Kconfig

@ -125,6 +125,8 @@ config TILEGX
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_KPROBES
select HAVE_KRETPROBES
config TILEPRO
def_bool !TILEGX

1
arch/tile/include/asm/Kbuild

@ -15,7 +15,6 @@ generic-y += ioctl.h
generic-y += ioctls.h
generic-y += ipcbuf.h
generic-y += irq_regs.h
generic-y += kdebug.h
generic-y += local.h
generic-y += msgbuf.h
generic-y += mutex.h

28
arch/tile/include/asm/kdebug.h

@ -0,0 +1,28 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _ASM_TILE_KDEBUG_H
#define _ASM_TILE_KDEBUG_H
#include <linux/notifier.h>
enum die_val {
DIE_OOPS = 1,
DIE_BREAK,
DIE_SSTEPBP,
DIE_PAGE_FAULT,
DIE_COMPILED_BPT
};
#endif /* _ASM_TILE_KDEBUG_H */

79
arch/tile/include/asm/kprobes.h

@ -0,0 +1,79 @@
/*
* arch/tile/include/asm/kprobes.h
*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _ASM_TILE_KPROBES_H
#define _ASM_TILE_KPROBES_H
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/percpu.h>
#include <arch/opcode.h>
#define __ARCH_WANT_KPROBES_INSN_SLOT
#define MAX_INSN_SIZE 2
#define kretprobe_blacklist_size 0
typedef tile_bundle_bits kprobe_opcode_t;
#define flush_insn_slot(p) \
flush_icache_range((unsigned long)p->addr, \
(unsigned long)p->addr + \
(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
struct kprobe;
/* Architecture specific copy of original instruction. */
struct arch_specific_insn {
kprobe_opcode_t *insn;
};
struct prev_kprobe {
struct kprobe *kp;
unsigned long status;
unsigned long saved_pc;
};
#define MAX_JPROBES_STACK_SIZE 128
#define MAX_JPROBES_STACK_ADDR \
(((unsigned long)current_thread_info()) + THREAD_SIZE - 32 \
- sizeof(struct pt_regs))
#define MIN_JPROBES_STACK_SIZE(ADDR) \
((((ADDR) + MAX_JPROBES_STACK_SIZE) > MAX_JPROBES_STACK_ADDR) \
? MAX_JPROBES_STACK_ADDR - (ADDR) \
: MAX_JPROBES_STACK_SIZE)
/* per-cpu kprobe control block. */
struct kprobe_ctlblk {
unsigned long kprobe_status;
unsigned long kprobe_saved_pc;
unsigned long jprobe_saved_sp;
struct prev_kprobe prev_kprobe;
struct pt_regs jprobe_saved_regs;
char jprobes_stack[MAX_JPROBES_STACK_SIZE];
};
extern tile_bundle_bits breakpoint2_insn;
extern tile_bundle_bits breakpoint_insn;
void arch_remove_kprobe(struct kprobe *);
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
#endif /* _ASM_TILE_KPROBES_H */

1
arch/tile/include/asm/ptrace.h

@ -33,6 +33,7 @@ typedef unsigned long pt_reg_t;
#ifndef __ASSEMBLY__
#define regs_return_value(regs) ((regs)->regs[0])
#define instruction_pointer(regs) ((regs)->pc)
#define profile_pc(regs) instruction_pointer(regs)
#define user_stack_pointer(regs) ((regs)->sp)

1
arch/tile/include/uapi/arch/opcode_tilegx.h

@ -61,6 +61,7 @@ typedef tilegx_bundle_bits tile_bundle_bits;
#define TILE_BUNDLE_ALIGNMENT_IN_BYTES TILEGX_BUNDLE_ALIGNMENT_IN_BYTES
#define TILE_LOG2_BUNDLE_ALIGNMENT_IN_BYTES \
TILEGX_LOG2_BUNDLE_ALIGNMENT_IN_BYTES
#define TILE_BPT_BUNDLE TILEGX_BPT_BUNDLE
/* 64-bit pattern for a { bpt ; nop } bundle. */
#define TILEGX_BPT_BUNDLE 0x286a44ae51485000ULL

1
arch/tile/include/uapi/arch/opcode_tilepro.h

@ -71,6 +71,7 @@ typedef tilepro_bundle_bits tile_bundle_bits;
#define TILE_BUNDLE_ALIGNMENT_IN_BYTES TILEPRO_BUNDLE_ALIGNMENT_IN_BYTES
#define TILE_LOG2_BUNDLE_ALIGNMENT_IN_BYTES \
TILEPRO_LOG2_BUNDLE_ALIGNMENT_IN_BYTES
#define TILE_BPT_BUNDLE TILEPRO_BPT_BUNDLE
/* 64-bit pattern for a { bpt ; nop } bundle. */
#define TILEPRO_BPT_BUNDLE 0x400b3cae70166000ULL

1
arch/tile/kernel/Makefile

@ -28,5 +28,6 @@ endif
obj-$(CONFIG_TILE_USB) += usb.o
obj-$(CONFIG_TILE_HVGLUE_TRACE) += hvglue_trace.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o mcount_64.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-y += vdso/

528
arch/tile/kernel/kprobes.c

@ -0,0 +1,528 @@
/*
* arch/tile/kernel/kprobes.c
* Kprobes on TILE-Gx
*
* Some portions copied from the MIPS version.
*
* Copyright (C) IBM Corporation, 2002, 2004
* Copyright 2006 Sony Corp.
* Copyright 2010 Cavium Networks
*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <arch/opcode.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
tile_bundle_bits breakpoint_insn = TILEGX_BPT_BUNDLE;
tile_bundle_bits breakpoint2_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP;
/*
* Check whether instruction is branch or jump, or if executing it
* has different results depending on where it is executed (e.g. lnk).
*/
static int __kprobes insn_has_control(kprobe_opcode_t insn)
{
if (get_Mode(insn) != 0) { /* Y-format bundle */
if (get_Opcode_Y1(insn) != RRR_1_OPCODE_Y1 ||
get_RRROpcodeExtension_Y1(insn) != UNARY_RRR_1_OPCODE_Y1)
return 0;
switch (get_UnaryOpcodeExtension_Y1(insn)) {
case JALRP_UNARY_OPCODE_Y1:
case JALR_UNARY_OPCODE_Y1:
case JRP_UNARY_OPCODE_Y1:
case JR_UNARY_OPCODE_Y1:
case LNK_UNARY_OPCODE_Y1:
return 1;
default:
return 0;
}
}
switch (get_Opcode_X1(insn)) {
case BRANCH_OPCODE_X1: /* branch instructions */
case JUMP_OPCODE_X1: /* jump instructions: j and jal */
return 1;
case RRR_0_OPCODE_X1: /* other jump instructions */
if (get_RRROpcodeExtension_X1(insn) != UNARY_RRR_0_OPCODE_X1)
return 0;
switch (get_UnaryOpcodeExtension_X1(insn)) {
case JALRP_UNARY_OPCODE_X1:
case JALR_UNARY_OPCODE_X1:
case JRP_UNARY_OPCODE_X1:
case JR_UNARY_OPCODE_X1:
case LNK_UNARY_OPCODE_X1:
return 1;
default:
return 0;
}
default:
return 0;
}
}
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
if (addr & (sizeof(kprobe_opcode_t) - 1))
return -EINVAL;
if (insn_has_control(*p->addr)) {
pr_notice("Kprobes for control instructions are not "
"supported\n");
return -EINVAL;
}
/* insn: must be on special executable page on tile. */
p->ainsn.insn = get_insn_slot();
if (!p->ainsn.insn)
return -ENOMEM;
/*
* In the kprobe->ainsn.insn[] array we store the original
* instruction at index zero and a break trap instruction at
* index one.
*/
memcpy(&p->ainsn.insn[0], p->addr, sizeof(kprobe_opcode_t));
p->ainsn.insn[1] = breakpoint2_insn;
p->opcode = *p->addr;
return 0;
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
unsigned long addr_wr;
/* Operate on writable kernel text mapping. */
addr_wr = (unsigned long)p->addr - MEM_SV_START + PAGE_OFFSET;
if (probe_kernel_write((void *)addr_wr, &breakpoint_insn,
sizeof(breakpoint_insn)))
pr_err("%s: failed to enable kprobe\n", __func__);
smp_wmb();
flush_insn_slot(p);
}
void __kprobes arch_disarm_kprobe(struct kprobe *kp)
{
unsigned long addr_wr;
/* Operate on writable kernel text mapping. */
addr_wr = (unsigned long)kp->addr - MEM_SV_START + PAGE_OFFSET;
if (probe_kernel_write((void *)addr_wr, &kp->opcode,
sizeof(kp->opcode)))
pr_err("%s: failed to enable kprobe\n", __func__);
smp_wmb();
flush_insn_slot(kp);
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
if (p->ainsn.insn) {
free_insn_slot(p->ainsn.insn, 0);
p->ainsn.insn = NULL;
}
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
kcb->prev_kprobe.saved_pc = kcb->kprobe_saved_pc;
}
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
kcb->kprobe_status = kcb->prev_kprobe.status;
kcb->kprobe_saved_pc = kcb->prev_kprobe.saved_pc;
}
static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, p);
kcb->kprobe_saved_pc = regs->pc;
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
/* Single step inline if the instruction is a break. */
if (p->opcode == breakpoint_insn ||
p->opcode == breakpoint2_insn)
regs->pc = (unsigned long)p->addr;
else
regs->pc = (unsigned long)&p->ainsn.insn[0];
}
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr;
struct kprobe_ctlblk *kcb;
addr = (kprobe_opcode_t *)regs->pc;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing.
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
/* Check we're not actually recursing. */
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if (kcb->kprobe_status == KPROBE_HIT_SS &&
p->ainsn.insn[0] == breakpoint_insn) {
goto no_kprobe;
}
/*
* We have reentered the kprobe_handler(), since
* another probe was hit while within the handler.
* We here save the original kprobes variables and
* just single step on the instruction of the new probe
* without calling any user handlers.
*/
save_previous_kprobe(kcb);
set_current_kprobe(p, regs, kcb);
kprobes_inc_nmissed_count(p);
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_REENTER;
return 1;
} else {
if (*addr != breakpoint_insn) {
/*
* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
goto no_kprobe;
}
p = __this_cpu_read(current_kprobe);
if (p->break_handler && p->break_handler(p, regs))
goto ss_probe;
}
goto no_kprobe;
}
p = get_kprobe(addr);
if (!p) {
if (*addr != breakpoint_insn) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
}
/* Not one of ours: let kernel handle it. */
goto no_kprobe;
}
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs)) {
/* Handler has already set things up, so skip ss setup. */
return 1;
}
ss_probe:
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
/*
* Called after single-stepping. p->addr is the address of the
* instruction that has been replaced by the breakpoint. To avoid the
* SMP problems that can occur when we temporarily put back the
* original opcode to single-step, we single-stepped a copy of the
* instruction. The address of this copy is p->ainsn.insn.
*
* This function prepares to return from the post-single-step
* breakpoint trap.
*/
static void __kprobes resume_execution(struct kprobe *p,
struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
unsigned long orig_pc = kcb->kprobe_saved_pc;
regs->pc = orig_pc + 8;
}
static inline int post_kprobe_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (!cur)
return 0;
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
resume_execution(cur, regs, kcb);
/* Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
}
reset_current_kprobe();
out:
preempt_enable_no_resched();
return 1;
}
static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
return 1;
if (kcb->kprobe_status & KPROBE_HIT_SS) {
/*
* We are here because the instruction being single
* stepped caused a page fault. We reset the current
* kprobe and the ip points back to the probe address
* and allow the page fault handler to continue as a
* normal page fault.
*/
resume_execution(cur, regs, kcb);
reset_current_kprobe();
preempt_enable_no_resched();
}
return 0;
}
/*
* Wrapper routine for handling exceptions.
*/
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;
switch (val) {
case DIE_BREAK:
if (kprobe_handler(args->regs))
ret = NOTIFY_STOP;
break;
case DIE_SSTEPBP:
if (post_kprobe_handler(args->regs))
ret = NOTIFY_STOP;
break;
case DIE_PAGE_FAULT:
/* kprobe_running() needs smp_processor_id(). */
preempt_disable();
if (kprobe_running()
&& kprobe_fault_handler(args->regs, args->trapnr))
ret = NOTIFY_STOP;
preempt_enable();
break;
default:
break;
}
return ret;
}
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
kcb->jprobe_saved_regs = *regs;
kcb->jprobe_saved_sp = regs->sp;
memcpy(kcb->jprobes_stack, (void *)kcb->jprobe_saved_sp,
MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp));
regs->pc = (unsigned long)(jp->entry);
return 1;
}
/* Defined in the inline asm below. */
void jprobe_return_end(void);
void __kprobes jprobe_return(void)
{
asm volatile(
"bpt\n\t"
".globl jprobe_return_end\n"
"jprobe_return_end:\n");
}
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (regs->pc >= (unsigned long)jprobe_return &&
regs->pc <= (unsigned long)jprobe_return_end) {
*regs = kcb->jprobe_saved_regs;
memcpy((void *)kcb->jprobe_saved_sp, kcb->jprobes_stack,
MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp));
preempt_enable_no_resched();
return 1;
}
return 0;
}
/*
* Function return probe trampoline:
* - init_kprobes() establishes a probepoint here
* - When the probed function returns, this probe causes the
* handlers to fire
*/
static void __used kretprobe_trampoline_holder(void)
{
asm volatile(
"nop\n\t"
".global kretprobe_trampoline\n"
"kretprobe_trampoline:\n\t"
"nop\n\t"
: : : "memory");
}
void kretprobe_trampoline(void);
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *) regs->lr;
/* Replace the return addr with trampoline addr */
regs->lr = (unsigned long)kretprobe_trampoline;
}
/*
* Called when the probe at kretprobe trampoline is hit.
*/
static int __kprobes trampoline_probe_handler(struct kprobe *p,
struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
struct hlist_node *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address = (unsigned long)kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
kretprobe_hash_lock(current, &head, &flags);
/*
* It is possible to have multiple instances associated with a given
* task either because multiple functions in the call path have
* a return probe installed on them, and/or more than one return
* return probe was registered for a target function.
*
* We can handle this because:
* - instances are always inserted at the head of the list
* - when multiple return probes are registered for the same
* function, the first instance's ret_addr will point to the
* real return address, and all the rest will point to
* kretprobe_trampoline
*/
hlist_for_each_entry_safe(ri, tmp, head, hlist) {
if (ri->task != current)
/* another task is sharing our hash bucket */
continue;
if (ri->rp && ri->rp->handler)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address) {
/*
* This is the real return address. Any other
* instances associated with this task are for
* other calls deeper on the call stack
*/
break;
}
}
kretprobe_assert(ri, orig_ret_address, trampoline_address);
instruction_pointer(regs) = orig_ret_address;
reset_current_kprobe();
kretprobe_hash_unlock(current, &flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
* to run (and have re-enabled preemption)
*/
return 1;
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
if (p->addr == (kprobe_opcode_t *)kretprobe_trampoline)
return 1;
return 0;
}
static struct kprobe trampoline_p = {
.addr = (kprobe_opcode_t *)kretprobe_trampoline,
.pre_handler = trampoline_probe_handler
};
int __init arch_init_kprobes(void)
{
register_kprobe(&trampoline_p);
return 0;
}

14
arch/tile/kernel/smp.c

@ -20,6 +20,7 @@
#include <linux/irq.h>
#include <linux/module.h>
#include <asm/cacheflush.h>
#include <asm/homecache.h>
HV_Topology smp_topology __write_once;
EXPORT_SYMBOL(smp_topology);
@ -167,9 +168,16 @@ static void ipi_flush_icache_range(void *info)
void flush_icache_range(unsigned long start, unsigned long end)
{
struct ipi_flush flush = { start, end };
preempt_disable();
on_each_cpu(ipi_flush_icache_range, &flush, 1);
preempt_enable();
/* If invoked with irqs disabled, we can not issue IPIs. */
if (irqs_disabled())
flush_remote(0, HV_FLUSH_EVICT_L1I, NULL, 0, 0, 0,
NULL, NULL, 0);
else {
preempt_disable();
on_each_cpu(ipi_flush_icache_range, &flush, 1);
preempt_enable();
}
}

45
arch/tile/kernel/traps.c

@ -15,6 +15,7 @@
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/uaccess.h>
@ -214,6 +215,43 @@ static const char *const int_name[] = {
#endif
};
static int do_bpt(struct pt_regs *regs)
{
unsigned long bundle, bcode, bpt;
bundle = *(unsigned long *)instruction_pointer(regs);
/*
* bpt shoule be { bpt; nop }, which is 0x286a44ae51485000ULL.
* we encode the unused least significant bits for other purpose.
*/
bpt = bundle & ~((1ULL << 12) - 1);
if (bpt != TILE_BPT_BUNDLE)
return 0;
bcode = bundle & ((1ULL << 12) - 1);
/*
* notify the kprobe handlers, if instruction is likely to
* pertain to them.
*/
switch (bcode) {
/* breakpoint_insn */
case 0:
notify_die(DIE_BREAK, "debug", regs, bundle,
INT_ILL, SIGTRAP);
break;
/* breakpoint2_insn */
case DIE_SSTEPBP:
notify_die(DIE_SSTEPBP, "single_step", regs, bundle,
INT_ILL, SIGTRAP);
break;
default:
return 0;
}
return 1;
}
void __kprobes do_trap(struct pt_regs *regs, int fault_num,
unsigned long reason)
{
@ -221,6 +259,11 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
int signo, code;
unsigned long address = 0;
bundle_bits instr;
int is_kernel = !user_mode(regs);
/* Handle breakpoints, etc. */
if (is_kernel && fault_num == INT_ILL && do_bpt(regs))
return;
/* Re-enable interrupts, if they were previously enabled. */
if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
@ -230,7 +273,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
* If it hits in kernel mode and we can't fix it up, just exit the
* current process and hope for the best.
*/
if (!user_mode(regs)) {
if (is_kernel) {
const char *name;
char buf[100];
if (fixup_exception(regs)) /* ILL_TRANS or UNALIGN_DATA */

1
arch/tile/kernel/vmlinux.lds.S

@ -43,6 +43,7 @@ SECTIONS
HEAD_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
__fix_text_end = .; /* tile-cpack won't rearrange before this */
TEXT_TEXT

12
arch/tile/mm/fault.c

@ -34,6 +34,7 @@
#include <linux/hugetlb.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/kdebug.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
@ -721,6 +722,17 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
{
int is_page_fault;
#ifdef CONFIG_KPROBES
/*
* This is to notify the fault handler of the kprobes. The
* exception code is redundant as it is also carried in REGS,
* but we pass it anyhow.
*/
if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
regs->faultnum, SIGSEGV) == NOTIFY_STOP)
return;
#endif
#ifdef __tilegx__
/*
* We don't need early do_page_fault_ics() support, since unlike

9
samples/kprobes/kprobe_example.c

@ -37,6 +37,11 @@ static int handler_pre(struct kprobe *p, struct pt_regs *regs)
" status = 0x%lx\n",
p->addr, regs->cp0_epc, regs->cp0_status);
#endif
#ifdef CONFIG_TILEGX
printk(KERN_INFO "pre_handler: p->addr = 0x%p, pc = 0x%lx,"
" ex1 = 0x%lx\n",
p->addr, regs->pc, regs->ex1);
#endif
/* A dump_stack() here will give a stack backtrace */
return 0;
@ -58,6 +63,10 @@ static void handler_post(struct kprobe *p, struct pt_regs *regs,
printk(KERN_INFO "post_handler: p->addr = 0x%p, status = 0x%lx\n",
p->addr, regs->cp0_status);
#endif
#ifdef CONFIG_TILEGX
printk(KERN_INFO "post_handler: p->addr = 0x%p, ex1 = 0x%lx\n",
p->addr, regs->ex1);
#endif
}
/*

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