849 lines
20 KiB
C
849 lines
20 KiB
C
/*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* 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. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*
|
|
* Copyright (C) 2009, 2010 ARM Limited
|
|
*
|
|
* Author: Will Deacon <will.deacon@arm.com>
|
|
*/
|
|
|
|
/*
|
|
* HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
|
|
* using the CPU's debug registers.
|
|
*/
|
|
#define pr_fmt(fmt) "hw-breakpoint: " fmt
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/perf_event.h>
|
|
#include <linux/hw_breakpoint.h>
|
|
#include <linux/smp.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/cputype.h>
|
|
#include <asm/current.h>
|
|
#include <asm/hw_breakpoint.h>
|
|
#include <asm/kdebug.h>
|
|
#include <asm/system.h>
|
|
#include <asm/traps.h>
|
|
|
|
/* Breakpoint currently in use for each BRP. */
|
|
static DEFINE_PER_CPU(struct perf_event *, bp_on_reg[ARM_MAX_BRP]);
|
|
|
|
/* Watchpoint currently in use for each WRP. */
|
|
static DEFINE_PER_CPU(struct perf_event *, wp_on_reg[ARM_MAX_WRP]);
|
|
|
|
/* Number of BRP/WRP registers on this CPU. */
|
|
static int core_num_brps;
|
|
static int core_num_wrps;
|
|
|
|
/* Debug architecture version. */
|
|
static u8 debug_arch;
|
|
|
|
/* Maximum supported watchpoint length. */
|
|
static u8 max_watchpoint_len;
|
|
|
|
/* Determine number of BRP registers available. */
|
|
static int get_num_brps(void)
|
|
{
|
|
u32 didr;
|
|
ARM_DBG_READ(c0, 0, didr);
|
|
return ((didr >> 24) & 0xf) + 1;
|
|
}
|
|
|
|
/* Determine number of WRP registers available. */
|
|
static int get_num_wrps(void)
|
|
{
|
|
/*
|
|
* FIXME: When a watchpoint fires, the only way to work out which
|
|
* watchpoint it was is by disassembling the faulting instruction
|
|
* and working out the address of the memory access.
|
|
*
|
|
* Furthermore, we can only do this if the watchpoint was precise
|
|
* since imprecise watchpoints prevent us from calculating register
|
|
* based addresses.
|
|
*
|
|
* For the time being, we only report 1 watchpoint register so we
|
|
* always know which watchpoint fired. In the future we can either
|
|
* add a disassembler and address generation emulator, or we can
|
|
* insert a check to see if the DFAR is set on watchpoint exception
|
|
* entry [the ARM ARM states that the DFAR is UNKNOWN, but
|
|
* experience shows that it is set on some implementations].
|
|
*/
|
|
|
|
#if 0
|
|
u32 didr, wrps;
|
|
ARM_DBG_READ(c0, 0, didr);
|
|
return ((didr >> 28) & 0xf) + 1;
|
|
#endif
|
|
|
|
return 1;
|
|
}
|
|
|
|
int hw_breakpoint_slots(int type)
|
|
{
|
|
/*
|
|
* We can be called early, so don't rely on
|
|
* our static variables being initialised.
|
|
*/
|
|
switch (type) {
|
|
case TYPE_INST:
|
|
return get_num_brps();
|
|
case TYPE_DATA:
|
|
return get_num_wrps();
|
|
default:
|
|
pr_warning("unknown slot type: %d\n", type);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* Determine debug architecture. */
|
|
static u8 get_debug_arch(void)
|
|
{
|
|
u32 didr;
|
|
|
|
/* Do we implement the extended CPUID interface? */
|
|
if (((read_cpuid_id() >> 16) & 0xf) != 0xf) {
|
|
pr_warning("CPUID feature registers not supported. "
|
|
"Assuming v6 debug is present.\n");
|
|
return ARM_DEBUG_ARCH_V6;
|
|
}
|
|
|
|
ARM_DBG_READ(c0, 0, didr);
|
|
return (didr >> 16) & 0xf;
|
|
}
|
|
|
|
/* Does this core support mismatch breakpoints? */
|
|
static int core_has_mismatch_bps(void)
|
|
{
|
|
return debug_arch >= ARM_DEBUG_ARCH_V7_ECP14 && core_num_brps > 1;
|
|
}
|
|
|
|
u8 arch_get_debug_arch(void)
|
|
{
|
|
return debug_arch;
|
|
}
|
|
|
|
#define READ_WB_REG_CASE(OP2, M, VAL) \
|
|
case ((OP2 << 4) + M): \
|
|
ARM_DBG_READ(c ## M, OP2, VAL); \
|
|
break
|
|
|
|
#define WRITE_WB_REG_CASE(OP2, M, VAL) \
|
|
case ((OP2 << 4) + M): \
|
|
ARM_DBG_WRITE(c ## M, OP2, VAL);\
|
|
break
|
|
|
|
#define GEN_READ_WB_REG_CASES(OP2, VAL) \
|
|
READ_WB_REG_CASE(OP2, 0, VAL); \
|
|
READ_WB_REG_CASE(OP2, 1, VAL); \
|
|
READ_WB_REG_CASE(OP2, 2, VAL); \
|
|
READ_WB_REG_CASE(OP2, 3, VAL); \
|
|
READ_WB_REG_CASE(OP2, 4, VAL); \
|
|
READ_WB_REG_CASE(OP2, 5, VAL); \
|
|
READ_WB_REG_CASE(OP2, 6, VAL); \
|
|
READ_WB_REG_CASE(OP2, 7, VAL); \
|
|
READ_WB_REG_CASE(OP2, 8, VAL); \
|
|
READ_WB_REG_CASE(OP2, 9, VAL); \
|
|
READ_WB_REG_CASE(OP2, 10, VAL); \
|
|
READ_WB_REG_CASE(OP2, 11, VAL); \
|
|
READ_WB_REG_CASE(OP2, 12, VAL); \
|
|
READ_WB_REG_CASE(OP2, 13, VAL); \
|
|
READ_WB_REG_CASE(OP2, 14, VAL); \
|
|
READ_WB_REG_CASE(OP2, 15, VAL)
|
|
|
|
#define GEN_WRITE_WB_REG_CASES(OP2, VAL) \
|
|
WRITE_WB_REG_CASE(OP2, 0, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 1, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 2, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 3, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 4, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 5, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 6, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 7, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 8, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 9, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 10, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 11, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 12, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 13, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 14, VAL); \
|
|
WRITE_WB_REG_CASE(OP2, 15, VAL)
|
|
|
|
static u32 read_wb_reg(int n)
|
|
{
|
|
u32 val = 0;
|
|
|
|
switch (n) {
|
|
GEN_READ_WB_REG_CASES(ARM_OP2_BVR, val);
|
|
GEN_READ_WB_REG_CASES(ARM_OP2_BCR, val);
|
|
GEN_READ_WB_REG_CASES(ARM_OP2_WVR, val);
|
|
GEN_READ_WB_REG_CASES(ARM_OP2_WCR, val);
|
|
default:
|
|
pr_warning("attempt to read from unknown breakpoint "
|
|
"register %d\n", n);
|
|
}
|
|
|
|
return val;
|
|
}
|
|
|
|
static void write_wb_reg(int n, u32 val)
|
|
{
|
|
switch (n) {
|
|
GEN_WRITE_WB_REG_CASES(ARM_OP2_BVR, val);
|
|
GEN_WRITE_WB_REG_CASES(ARM_OP2_BCR, val);
|
|
GEN_WRITE_WB_REG_CASES(ARM_OP2_WVR, val);
|
|
GEN_WRITE_WB_REG_CASES(ARM_OP2_WCR, val);
|
|
default:
|
|
pr_warning("attempt to write to unknown breakpoint "
|
|
"register %d\n", n);
|
|
}
|
|
isb();
|
|
}
|
|
|
|
/*
|
|
* In order to access the breakpoint/watchpoint control registers,
|
|
* we must be running in debug monitor mode. Unfortunately, we can
|
|
* be put into halting debug mode at any time by an external debugger
|
|
* but there is nothing we can do to prevent that.
|
|
*/
|
|
static int enable_monitor_mode(void)
|
|
{
|
|
u32 dscr;
|
|
int ret = 0;
|
|
|
|
ARM_DBG_READ(c1, 0, dscr);
|
|
|
|
/* Ensure that halting mode is disabled. */
|
|
if (WARN_ONCE(dscr & ARM_DSCR_HDBGEN, "halting debug mode enabled."
|
|
"Unable to access hardware resources.")) {
|
|
ret = -EPERM;
|
|
goto out;
|
|
}
|
|
|
|
/* Write to the corresponding DSCR. */
|
|
switch (debug_arch) {
|
|
case ARM_DEBUG_ARCH_V6:
|
|
case ARM_DEBUG_ARCH_V6_1:
|
|
ARM_DBG_WRITE(c1, 0, (dscr | ARM_DSCR_MDBGEN));
|
|
break;
|
|
case ARM_DEBUG_ARCH_V7_ECP14:
|
|
ARM_DBG_WRITE(c2, 2, (dscr | ARM_DSCR_MDBGEN));
|
|
break;
|
|
default:
|
|
ret = -ENODEV;
|
|
goto out;
|
|
}
|
|
|
|
/* Check that the write made it through. */
|
|
ARM_DBG_READ(c1, 0, dscr);
|
|
if (WARN_ONCE(!(dscr & ARM_DSCR_MDBGEN),
|
|
"failed to enable monitor mode.")) {
|
|
ret = -EPERM;
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Check if 8-bit byte-address select is available.
|
|
* This clobbers WRP 0.
|
|
*/
|
|
static u8 get_max_wp_len(void)
|
|
{
|
|
u32 ctrl_reg;
|
|
struct arch_hw_breakpoint_ctrl ctrl;
|
|
u8 size = 4;
|
|
|
|
if (debug_arch < ARM_DEBUG_ARCH_V7_ECP14)
|
|
goto out;
|
|
|
|
if (enable_monitor_mode())
|
|
goto out;
|
|
|
|
memset(&ctrl, 0, sizeof(ctrl));
|
|
ctrl.len = ARM_BREAKPOINT_LEN_8;
|
|
ctrl_reg = encode_ctrl_reg(ctrl);
|
|
|
|
write_wb_reg(ARM_BASE_WVR, 0);
|
|
write_wb_reg(ARM_BASE_WCR, ctrl_reg);
|
|
if ((read_wb_reg(ARM_BASE_WCR) & ctrl_reg) == ctrl_reg)
|
|
size = 8;
|
|
|
|
out:
|
|
return size;
|
|
}
|
|
|
|
u8 arch_get_max_wp_len(void)
|
|
{
|
|
return max_watchpoint_len;
|
|
}
|
|
|
|
/*
|
|
* Handler for reactivating a suspended watchpoint when the single
|
|
* step `mismatch' breakpoint is triggered.
|
|
*/
|
|
static void wp_single_step_handler(struct perf_event *bp, int unused,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
perf_event_enable(counter_arch_bp(bp)->suspended_wp);
|
|
unregister_hw_breakpoint(bp);
|
|
}
|
|
|
|
static int bp_is_single_step(struct perf_event *bp)
|
|
{
|
|
return bp->overflow_handler == wp_single_step_handler;
|
|
}
|
|
|
|
/*
|
|
* Install a perf counter breakpoint.
|
|
*/
|
|
int arch_install_hw_breakpoint(struct perf_event *bp)
|
|
{
|
|
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
|
|
struct perf_event **slot, **slots;
|
|
int i, max_slots, ctrl_base, val_base, ret = 0;
|
|
|
|
/* Ensure that we are in monitor mode and halting mode is disabled. */
|
|
ret = enable_monitor_mode();
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
|
|
/* Breakpoint */
|
|
ctrl_base = ARM_BASE_BCR;
|
|
val_base = ARM_BASE_BVR;
|
|
slots = __get_cpu_var(bp_on_reg);
|
|
max_slots = core_num_brps - 1;
|
|
|
|
if (bp_is_single_step(bp)) {
|
|
info->ctrl.mismatch = 1;
|
|
i = max_slots;
|
|
slots[i] = bp;
|
|
goto setup;
|
|
}
|
|
} else {
|
|
/* Watchpoint */
|
|
ctrl_base = ARM_BASE_WCR;
|
|
val_base = ARM_BASE_WVR;
|
|
slots = __get_cpu_var(wp_on_reg);
|
|
max_slots = core_num_wrps;
|
|
}
|
|
|
|
for (i = 0; i < max_slots; ++i) {
|
|
slot = &slots[i];
|
|
|
|
if (!*slot) {
|
|
*slot = bp;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot")) {
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
setup:
|
|
/* Setup the address register. */
|
|
write_wb_reg(val_base + i, info->address);
|
|
|
|
/* Setup the control register. */
|
|
write_wb_reg(ctrl_base + i, encode_ctrl_reg(info->ctrl) | 0x1);
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void arch_uninstall_hw_breakpoint(struct perf_event *bp)
|
|
{
|
|
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
|
|
struct perf_event **slot, **slots;
|
|
int i, max_slots, base;
|
|
|
|
if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
|
|
/* Breakpoint */
|
|
base = ARM_BASE_BCR;
|
|
slots = __get_cpu_var(bp_on_reg);
|
|
max_slots = core_num_brps - 1;
|
|
|
|
if (bp_is_single_step(bp)) {
|
|
i = max_slots;
|
|
slots[i] = NULL;
|
|
goto reset;
|
|
}
|
|
} else {
|
|
/* Watchpoint */
|
|
base = ARM_BASE_WCR;
|
|
slots = __get_cpu_var(wp_on_reg);
|
|
max_slots = core_num_wrps;
|
|
}
|
|
|
|
/* Remove the breakpoint. */
|
|
for (i = 0; i < max_slots; ++i) {
|
|
slot = &slots[i];
|
|
|
|
if (*slot == bp) {
|
|
*slot = NULL;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
|
|
return;
|
|
|
|
reset:
|
|
/* Reset the control register. */
|
|
write_wb_reg(base + i, 0);
|
|
}
|
|
|
|
static int get_hbp_len(u8 hbp_len)
|
|
{
|
|
unsigned int len_in_bytes = 0;
|
|
|
|
switch (hbp_len) {
|
|
case ARM_BREAKPOINT_LEN_1:
|
|
len_in_bytes = 1;
|
|
break;
|
|
case ARM_BREAKPOINT_LEN_2:
|
|
len_in_bytes = 2;
|
|
break;
|
|
case ARM_BREAKPOINT_LEN_4:
|
|
len_in_bytes = 4;
|
|
break;
|
|
case ARM_BREAKPOINT_LEN_8:
|
|
len_in_bytes = 8;
|
|
break;
|
|
}
|
|
|
|
return len_in_bytes;
|
|
}
|
|
|
|
/*
|
|
* Check whether bp virtual address is in kernel space.
|
|
*/
|
|
int arch_check_bp_in_kernelspace(struct perf_event *bp)
|
|
{
|
|
unsigned int len;
|
|
unsigned long va;
|
|
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
|
|
|
|
va = info->address;
|
|
len = get_hbp_len(info->ctrl.len);
|
|
|
|
return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
|
|
}
|
|
|
|
/*
|
|
* Extract generic type and length encodings from an arch_hw_breakpoint_ctrl.
|
|
* Hopefully this will disappear when ptrace can bypass the conversion
|
|
* to generic breakpoint descriptions.
|
|
*/
|
|
int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,
|
|
int *gen_len, int *gen_type)
|
|
{
|
|
/* Type */
|
|
switch (ctrl.type) {
|
|
case ARM_BREAKPOINT_EXECUTE:
|
|
*gen_type = HW_BREAKPOINT_X;
|
|
break;
|
|
case ARM_BREAKPOINT_LOAD:
|
|
*gen_type = HW_BREAKPOINT_R;
|
|
break;
|
|
case ARM_BREAKPOINT_STORE:
|
|
*gen_type = HW_BREAKPOINT_W;
|
|
break;
|
|
case ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE:
|
|
*gen_type = HW_BREAKPOINT_RW;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Len */
|
|
switch (ctrl.len) {
|
|
case ARM_BREAKPOINT_LEN_1:
|
|
*gen_len = HW_BREAKPOINT_LEN_1;
|
|
break;
|
|
case ARM_BREAKPOINT_LEN_2:
|
|
*gen_len = HW_BREAKPOINT_LEN_2;
|
|
break;
|
|
case ARM_BREAKPOINT_LEN_4:
|
|
*gen_len = HW_BREAKPOINT_LEN_4;
|
|
break;
|
|
case ARM_BREAKPOINT_LEN_8:
|
|
*gen_len = HW_BREAKPOINT_LEN_8;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Construct an arch_hw_breakpoint from a perf_event.
|
|
*/
|
|
static int arch_build_bp_info(struct perf_event *bp)
|
|
{
|
|
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
|
|
|
|
/* Type */
|
|
switch (bp->attr.bp_type) {
|
|
case HW_BREAKPOINT_X:
|
|
info->ctrl.type = ARM_BREAKPOINT_EXECUTE;
|
|
break;
|
|
case HW_BREAKPOINT_R:
|
|
info->ctrl.type = ARM_BREAKPOINT_LOAD;
|
|
break;
|
|
case HW_BREAKPOINT_W:
|
|
info->ctrl.type = ARM_BREAKPOINT_STORE;
|
|
break;
|
|
case HW_BREAKPOINT_RW:
|
|
info->ctrl.type = ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Len */
|
|
switch (bp->attr.bp_len) {
|
|
case HW_BREAKPOINT_LEN_1:
|
|
info->ctrl.len = ARM_BREAKPOINT_LEN_1;
|
|
break;
|
|
case HW_BREAKPOINT_LEN_2:
|
|
info->ctrl.len = ARM_BREAKPOINT_LEN_2;
|
|
break;
|
|
case HW_BREAKPOINT_LEN_4:
|
|
info->ctrl.len = ARM_BREAKPOINT_LEN_4;
|
|
break;
|
|
case HW_BREAKPOINT_LEN_8:
|
|
info->ctrl.len = ARM_BREAKPOINT_LEN_8;
|
|
if ((info->ctrl.type != ARM_BREAKPOINT_EXECUTE)
|
|
&& max_watchpoint_len >= 8)
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Address */
|
|
info->address = bp->attr.bp_addr;
|
|
|
|
/* Privilege */
|
|
info->ctrl.privilege = ARM_BREAKPOINT_USER;
|
|
if (arch_check_bp_in_kernelspace(bp) && !bp_is_single_step(bp))
|
|
info->ctrl.privilege |= ARM_BREAKPOINT_PRIV;
|
|
|
|
/* Enabled? */
|
|
info->ctrl.enabled = !bp->attr.disabled;
|
|
|
|
/* Mismatch */
|
|
info->ctrl.mismatch = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Validate the arch-specific HW Breakpoint register settings.
|
|
*/
|
|
int arch_validate_hwbkpt_settings(struct perf_event *bp)
|
|
{
|
|
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
|
|
int ret = 0;
|
|
u32 bytelen, max_len, offset, alignment_mask = 0x3;
|
|
|
|
/* Build the arch_hw_breakpoint. */
|
|
ret = arch_build_bp_info(bp);
|
|
if (ret)
|
|
goto out;
|
|
|
|
/* Check address alignment. */
|
|
if (info->ctrl.len == ARM_BREAKPOINT_LEN_8)
|
|
alignment_mask = 0x7;
|
|
if (info->address & alignment_mask) {
|
|
/*
|
|
* Try to fix the alignment. This may result in a length
|
|
* that is too large, so we must check for that.
|
|
*/
|
|
bytelen = get_hbp_len(info->ctrl.len);
|
|
max_len = info->ctrl.type == ARM_BREAKPOINT_EXECUTE ? 4 :
|
|
max_watchpoint_len;
|
|
|
|
if (max_len >= 8)
|
|
offset = info->address & 0x7;
|
|
else
|
|
offset = info->address & 0x3;
|
|
|
|
if (bytelen > (1 << ((max_len - (offset + 1)) >> 1))) {
|
|
ret = -EFBIG;
|
|
goto out;
|
|
}
|
|
|
|
info->ctrl.len <<= offset;
|
|
info->address &= ~offset;
|
|
|
|
pr_debug("breakpoint alignment fixup: length = 0x%x, "
|
|
"address = 0x%x\n", info->ctrl.len, info->address);
|
|
}
|
|
|
|
/*
|
|
* Currently we rely on an overflow handler to take
|
|
* care of single-stepping the breakpoint when it fires.
|
|
* In the case of userspace breakpoints on a core with V7 debug,
|
|
* we can use the mismatch feature as a poor-man's hardware single-step.
|
|
*/
|
|
if (WARN_ONCE(!bp->overflow_handler &&
|
|
(arch_check_bp_in_kernelspace(bp) || !core_has_mismatch_bps()),
|
|
"overflow handler required but none found")) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void update_mismatch_flag(int idx, int flag)
|
|
{
|
|
struct perf_event *bp = __get_cpu_var(bp_on_reg[idx]);
|
|
struct arch_hw_breakpoint *info;
|
|
|
|
if (bp == NULL)
|
|
return;
|
|
|
|
info = counter_arch_bp(bp);
|
|
|
|
/* Update the mismatch field to enter/exit `single-step' mode */
|
|
if (!bp->overflow_handler && info->ctrl.mismatch != flag) {
|
|
info->ctrl.mismatch = flag;
|
|
write_wb_reg(ARM_BASE_BCR + idx, encode_ctrl_reg(info->ctrl) | 0x1);
|
|
}
|
|
}
|
|
|
|
static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
|
|
{
|
|
int i;
|
|
struct perf_event *bp, **slots = __get_cpu_var(wp_on_reg);
|
|
struct arch_hw_breakpoint *info;
|
|
struct perf_event_attr attr;
|
|
|
|
/* Without a disassembler, we can only handle 1 watchpoint. */
|
|
BUG_ON(core_num_wrps > 1);
|
|
|
|
hw_breakpoint_init(&attr);
|
|
attr.bp_addr = regs->ARM_pc & ~0x3;
|
|
attr.bp_len = HW_BREAKPOINT_LEN_4;
|
|
attr.bp_type = HW_BREAKPOINT_X;
|
|
|
|
for (i = 0; i < core_num_wrps; ++i) {
|
|
rcu_read_lock();
|
|
|
|
if (slots[i] == NULL) {
|
|
rcu_read_unlock();
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The DFAR is an unknown value. Since we only allow a
|
|
* single watchpoint, we can set the trigger to the lowest
|
|
* possible faulting address.
|
|
*/
|
|
info = counter_arch_bp(slots[i]);
|
|
info->trigger = slots[i]->attr.bp_addr;
|
|
pr_debug("watchpoint fired: address = 0x%x\n", info->trigger);
|
|
perf_bp_event(slots[i], regs);
|
|
|
|
/*
|
|
* If no overflow handler is present, insert a temporary
|
|
* mismatch breakpoint so we can single-step over the
|
|
* watchpoint trigger.
|
|
*/
|
|
if (!slots[i]->overflow_handler) {
|
|
bp = register_user_hw_breakpoint(&attr,
|
|
wp_single_step_handler,
|
|
current);
|
|
counter_arch_bp(bp)->suspended_wp = slots[i];
|
|
perf_event_disable(slots[i]);
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
}
|
|
|
|
static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
|
|
{
|
|
int i;
|
|
int mismatch;
|
|
u32 ctrl_reg, val, addr;
|
|
struct perf_event *bp, **slots = __get_cpu_var(bp_on_reg);
|
|
struct arch_hw_breakpoint *info;
|
|
struct arch_hw_breakpoint_ctrl ctrl;
|
|
|
|
/* The exception entry code places the amended lr in the PC. */
|
|
addr = regs->ARM_pc;
|
|
|
|
for (i = 0; i < core_num_brps; ++i) {
|
|
rcu_read_lock();
|
|
|
|
bp = slots[i];
|
|
|
|
if (bp == NULL) {
|
|
rcu_read_unlock();
|
|
continue;
|
|
}
|
|
|
|
mismatch = 0;
|
|
|
|
/* Check if the breakpoint value matches. */
|
|
val = read_wb_reg(ARM_BASE_BVR + i);
|
|
if (val != (addr & ~0x3))
|
|
goto unlock;
|
|
|
|
/* Possible match, check the byte address select to confirm. */
|
|
ctrl_reg = read_wb_reg(ARM_BASE_BCR + i);
|
|
decode_ctrl_reg(ctrl_reg, &ctrl);
|
|
if ((1 << (addr & 0x3)) & ctrl.len) {
|
|
mismatch = 1;
|
|
info = counter_arch_bp(bp);
|
|
info->trigger = addr;
|
|
}
|
|
|
|
unlock:
|
|
if ((mismatch && !info->ctrl.mismatch) || bp_is_single_step(bp)) {
|
|
pr_debug("breakpoint fired: address = 0x%x\n", addr);
|
|
perf_bp_event(bp, regs);
|
|
}
|
|
|
|
update_mismatch_flag(i, mismatch);
|
|
rcu_read_unlock();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called from either the Data Abort Handler [watchpoint] or the
|
|
* Prefetch Abort Handler [breakpoint].
|
|
*/
|
|
static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
|
|
struct pt_regs *regs)
|
|
{
|
|
int ret = 1; /* Unhandled fault. */
|
|
u32 dscr;
|
|
|
|
/* We only handle watchpoints and hardware breakpoints. */
|
|
ARM_DBG_READ(c1, 0, dscr);
|
|
|
|
/* Perform perf callbacks. */
|
|
switch (ARM_DSCR_MOE(dscr)) {
|
|
case ARM_ENTRY_BREAKPOINT:
|
|
breakpoint_handler(addr, regs);
|
|
break;
|
|
case ARM_ENTRY_ASYNC_WATCHPOINT:
|
|
WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n");
|
|
case ARM_ENTRY_SYNC_WATCHPOINT:
|
|
watchpoint_handler(addr, regs);
|
|
break;
|
|
default:
|
|
goto out;
|
|
}
|
|
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* One-time initialisation.
|
|
*/
|
|
static void __init reset_ctrl_regs(void *unused)
|
|
{
|
|
int i;
|
|
|
|
if (enable_monitor_mode())
|
|
return;
|
|
|
|
for (i = 0; i < core_num_brps; ++i) {
|
|
write_wb_reg(ARM_BASE_BCR + i, 0UL);
|
|
write_wb_reg(ARM_BASE_BVR + i, 0UL);
|
|
}
|
|
|
|
for (i = 0; i < core_num_wrps; ++i) {
|
|
write_wb_reg(ARM_BASE_WCR + i, 0UL);
|
|
write_wb_reg(ARM_BASE_WVR + i, 0UL);
|
|
}
|
|
}
|
|
|
|
static int __init arch_hw_breakpoint_init(void)
|
|
{
|
|
int ret = 0;
|
|
u32 dscr;
|
|
|
|
debug_arch = get_debug_arch();
|
|
|
|
if (debug_arch > ARM_DEBUG_ARCH_V7_ECP14) {
|
|
pr_info("debug architecture 0x%x unsupported.\n", debug_arch);
|
|
ret = -ENODEV;
|
|
goto out;
|
|
}
|
|
|
|
/* Determine how many BRPs/WRPs are available. */
|
|
core_num_brps = get_num_brps();
|
|
core_num_wrps = get_num_wrps();
|
|
|
|
pr_info("found %d breakpoint and %d watchpoint registers.\n",
|
|
core_num_brps, core_num_wrps);
|
|
|
|
if (core_has_mismatch_bps())
|
|
pr_info("1 breakpoint reserved for watchpoint single-step.\n");
|
|
|
|
ARM_DBG_READ(c1, 0, dscr);
|
|
if (dscr & ARM_DSCR_HDBGEN) {
|
|
pr_warning("halting debug mode enabled. Assuming maximum "
|
|
"watchpoint size of 4 bytes.");
|
|
} else {
|
|
/* Work out the maximum supported watchpoint length. */
|
|
max_watchpoint_len = get_max_wp_len();
|
|
pr_info("maximum watchpoint size is %u bytes.\n",
|
|
max_watchpoint_len);
|
|
|
|
/*
|
|
* Reset the breakpoint resources. We assume that a halting
|
|
* debugger will leave the world in a nice state for us.
|
|
*/
|
|
smp_call_function(reset_ctrl_regs, NULL, 1);
|
|
reset_ctrl_regs(NULL);
|
|
}
|
|
|
|
/* Register debug fault handler. */
|
|
hook_fault_code(2, hw_breakpoint_pending, SIGTRAP, TRAP_HWBKPT,
|
|
"watchpoint debug exception");
|
|
hook_ifault_code(2, hw_breakpoint_pending, SIGTRAP, TRAP_HWBKPT,
|
|
"breakpoint debug exception");
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
arch_initcall(arch_hw_breakpoint_init);
|
|
|
|
void hw_breakpoint_pmu_read(struct perf_event *bp)
|
|
{
|
|
}
|
|
|
|
/*
|
|
* Dummy function to register with die_notifier.
|
|
*/
|
|
int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
|
|
unsigned long val, void *data)
|
|
{
|
|
return NOTIFY_DONE;
|
|
}
|