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-rw-r--r--arch/x86/kernel/kgdb.c222
-rw-r--r--include/linux/hw_breakpoint.h2
-rw-r--r--kernel/hw_breakpoint.c56
-rw-r--r--kernel/kgdb.c3
-rw-r--r--tools/perf/.gitignore1
-rw-r--r--tools/perf/builtin-report.c2
6 files changed, 218 insertions, 68 deletions
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index dd74fe7273b..bfba6019d76 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -42,6 +42,7 @@
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/nmi.h>
+#include <linux/hw_breakpoint.h>
#include <asm/debugreg.h>
#include <asm/apicdef.h>
@@ -204,40 +205,81 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
static struct hw_breakpoint {
unsigned enabled;
- unsigned type;
- unsigned len;
unsigned long addr;
+ int len;
+ int type;
+ struct perf_event **pev;
} breakinfo[4];
static void kgdb_correct_hw_break(void)
{
- unsigned long dr7;
- int correctit = 0;
- int breakbit;
int breakno;
- get_debugreg(dr7, 7);
for (breakno = 0; breakno < 4; breakno++) {
- breakbit = 2 << (breakno << 1);
- if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
- correctit = 1;
- dr7 |= breakbit;
- dr7 &= ~(0xf0000 << (breakno << 2));
- dr7 |= ((breakinfo[breakno].len << 2) |
- breakinfo[breakno].type) <<
- ((breakno << 2) + 16);
- set_debugreg(breakinfo[breakno].addr, breakno);
-
- } else {
- if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
- correctit = 1;
- dr7 &= ~breakbit;
- dr7 &= ~(0xf0000 << (breakno << 2));
- }
- }
+ struct perf_event *bp;
+ struct arch_hw_breakpoint *info;
+ int val;
+ int cpu = raw_smp_processor_id();
+ if (!breakinfo[breakno].enabled)
+ continue;
+ bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ info = counter_arch_bp(bp);
+ if (bp->attr.disabled != 1)
+ continue;
+ bp->attr.bp_addr = breakinfo[breakno].addr;
+ bp->attr.bp_len = breakinfo[breakno].len;
+ bp->attr.bp_type = breakinfo[breakno].type;
+ info->address = breakinfo[breakno].addr;
+ info->len = breakinfo[breakno].len;
+ info->type = breakinfo[breakno].type;
+ val = arch_install_hw_breakpoint(bp);
+ if (!val)
+ bp->attr.disabled = 0;
+ }
+ hw_breakpoint_restore();
+}
+
+static int hw_break_reserve_slot(int breakno)
+{
+ int cpu;
+ int cnt = 0;
+ struct perf_event **pevent;
+
+ for_each_online_cpu(cpu) {
+ cnt++;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_reserve_bp_slot(*pevent))
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ for_each_online_cpu(cpu) {
+ cnt--;
+ if (!cnt)
+ break;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ dbg_release_bp_slot(*pevent);
}
- if (correctit)
- set_debugreg(dr7, 7);
+ return -1;
+}
+
+static int hw_break_release_slot(int breakno)
+{
+ struct perf_event **pevent;
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_release_bp_slot(*pevent))
+ /*
+ * The debugger is responisble for handing the retry on
+ * remove failure.
+ */
+ return -1;
+ }
+ return 0;
}
static int
@@ -251,6 +293,10 @@ kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
if (i == 4)
return -1;
+ if (hw_break_release_slot(i)) {
+ printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr);
+ return -1;
+ }
breakinfo[i].enabled = 0;
return 0;
@@ -259,15 +305,23 @@ kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
static void kgdb_remove_all_hw_break(void)
{
int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
- for (i = 0; i < 4; i++)
- memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
+ for (i = 0; i < 4; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (bp->attr.disabled == 1)
+ continue;
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ }
}
static int
kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
{
- unsigned type;
int i;
for (i = 0; i < 4; i++)
@@ -278,27 +332,42 @@ kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
switch (bptype) {
case BP_HARDWARE_BREAKPOINT:
- type = 0;
- len = 1;
+ len = 1;
+ breakinfo[i].type = X86_BREAKPOINT_EXECUTE;
break;
case BP_WRITE_WATCHPOINT:
- type = 1;
+ breakinfo[i].type = X86_BREAKPOINT_WRITE;
break;
case BP_ACCESS_WATCHPOINT:
- type = 3;
+ breakinfo[i].type = X86_BREAKPOINT_RW;
break;
default:
return -1;
}
-
- if (len == 1 || len == 2 || len == 4)
- breakinfo[i].len = len - 1;
- else
+ switch (len) {
+ case 1:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_1;
+ break;
+ case 2:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_2;
+ break;
+ case 4:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_4;
+ break;
+#ifdef CONFIG_X86_64
+ case 8:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_8;
+ break;
+#endif
+ default:
return -1;
-
- breakinfo[i].enabled = 1;
+ }
breakinfo[i].addr = addr;
- breakinfo[i].type = type;
+ if (hw_break_reserve_slot(i)) {
+ breakinfo[i].addr = 0;
+ return -1;
+ }
+ breakinfo[i].enabled = 1;
return 0;
}
@@ -313,8 +382,21 @@ kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
*/
void kgdb_disable_hw_debug(struct pt_regs *regs)
{
+ int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
+
/* Disable hardware debugging while we are in kgdb: */
set_debugreg(0UL, 7);
+ for (i = 0; i < 4; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (bp->attr.disabled == 1)
+ continue;
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ }
}
/**
@@ -378,7 +460,6 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
struct pt_regs *linux_regs)
{
unsigned long addr;
- unsigned long dr6;
char *ptr;
int newPC;
@@ -404,20 +485,6 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
raw_smp_processor_id());
}
- get_debugreg(dr6, 6);
- if (!(dr6 & 0x4000)) {
- int breakno;
-
- for (breakno = 0; breakno < 4; breakno++) {
- if (dr6 & (1 << breakno) &&
- breakinfo[breakno].type == 0) {
- /* Set restore flag: */
- linux_regs->flags |= X86_EFLAGS_RF;
- break;
- }
- }
- }
- set_debugreg(0UL, 6);
kgdb_correct_hw_break();
return 0;
@@ -485,8 +552,7 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
break;
case DIE_DEBUG:
- if (atomic_read(&kgdb_cpu_doing_single_step) ==
- raw_smp_processor_id()) {
+ if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
if (user_mode(regs))
return single_step_cont(regs, args);
break;
@@ -539,7 +605,42 @@ static struct notifier_block kgdb_notifier = {
*/
int kgdb_arch_init(void)
{
- return register_die_notifier(&kgdb_notifier);
+ int i, cpu;
+ int ret;
+ struct perf_event_attr attr;
+ struct perf_event **pevent;
+
+ ret = register_die_notifier(&kgdb_notifier);
+ if (ret != 0)
+ return ret;
+ /*
+ * Pre-allocate the hw breakpoint structions in the non-atomic
+ * portion of kgdb because this operation requires mutexs to
+ * complete.
+ */
+ attr.bp_addr = (unsigned long)kgdb_arch_init;
+ attr.type = PERF_TYPE_BREAKPOINT;
+ attr.bp_len = HW_BREAKPOINT_LEN_1;
+ attr.bp_type = HW_BREAKPOINT_W;
+ attr.disabled = 1;
+ for (i = 0; i < 4; i++) {
+ breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
+ if (IS_ERR(breakinfo[i].pev)) {
+ printk(KERN_ERR "kgdb: Could not allocate hw breakpoints\n");
+ breakinfo[i].pev = NULL;
+ kgdb_arch_exit();
+ return -1;
+ }
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
+ pevent[0]->hw.sample_period = 1;
+ if (pevent[0]->destroy != NULL) {
+ pevent[0]->destroy = NULL;
+ release_bp_slot(*pevent);
+ }
+ }
+ }
+ return ret;
}
/**
@@ -550,6 +651,13 @@ int kgdb_arch_init(void)
*/
void kgdb_arch_exit(void)
{
+ int i;
+ for (i = 0; i < 4; i++) {
+ if (breakinfo[i].pev) {
+ unregister_wide_hw_breakpoint(breakinfo[i].pev);
+ breakinfo[i].pev = NULL;
+ }
+ }
unregister_die_notifier(&kgdb_notifier);
}
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index 41235c93e4e..070ba062173 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -75,6 +75,8 @@ extern int __register_perf_hw_breakpoint(struct perf_event *bp);
extern void unregister_hw_breakpoint(struct perf_event *bp);
extern void unregister_wide_hw_breakpoint(struct perf_event **cpu_events);
+extern int dbg_reserve_bp_slot(struct perf_event *bp);
+extern int dbg_release_bp_slot(struct perf_event *bp);
extern int reserve_bp_slot(struct perf_event *bp);
extern void release_bp_slot(struct perf_event *bp);
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 50dbd599958..8a5c7d55ac9 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -243,38 +243,70 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable)
* ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *))
* + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM
*/
-int reserve_bp_slot(struct perf_event *bp)
+static int __reserve_bp_slot(struct perf_event *bp)
{
struct bp_busy_slots slots = {0};
- int ret = 0;
-
- mutex_lock(&nr_bp_mutex);
fetch_bp_busy_slots(&slots, bp);
/* Flexible counters need to keep at least one slot */
- if (slots.pinned + (!!slots.flexible) == HBP_NUM) {
- ret = -ENOSPC;
- goto end;
- }
+ if (slots.pinned + (!!slots.flexible) == HBP_NUM)
+ return -ENOSPC;
toggle_bp_slot(bp, true);
-end:
+ return 0;
+}
+
+int reserve_bp_slot(struct perf_event *bp)
+{
+ int ret;
+
+ mutex_lock(&nr_bp_mutex);
+
+ ret = __reserve_bp_slot(bp);
+
mutex_unlock(&nr_bp_mutex);
return ret;
}
+static void __release_bp_slot(struct perf_event *bp)
+{
+ toggle_bp_slot(bp, false);
+}
+
void release_bp_slot(struct perf_event *bp)
{
mutex_lock(&nr_bp_mutex);
- toggle_bp_slot(bp, false);
+ __release_bp_slot(bp);
mutex_unlock(&nr_bp_mutex);
}
+/*
+ * Allow the kernel debugger to reserve breakpoint slots without
+ * taking a lock using the dbg_* variant of for the reserve and
+ * release breakpoint slots.
+ */
+int dbg_reserve_bp_slot(struct perf_event *bp)
+{
+ if (mutex_is_locked(&nr_bp_mutex))
+ return -1;
+
+ return __reserve_bp_slot(bp);
+}
+
+int dbg_release_bp_slot(struct perf_event *bp)
+{
+ if (mutex_is_locked(&nr_bp_mutex))
+ return -1;
+
+ __release_bp_slot(bp);
+
+ return 0;
+}
int register_perf_hw_breakpoint(struct perf_event *bp)
{
@@ -296,6 +328,10 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
if (!bp->attr.disabled || !bp->overflow_handler)
ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
+ /* if arch_validate_hwbkpt_settings() fails then release bp slot */
+ if (ret)
+ release_bp_slot(bp);
+
return ret;
}
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 2eb517e2351..c7ade62e4ef 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -583,6 +583,9 @@ static void kgdb_wait(struct pt_regs *regs)
smp_wmb();
atomic_set(&cpu_in_kgdb[cpu], 1);
+ /* Disable any cpu specific hw breakpoints */
+ kgdb_disable_hw_debug(regs);
+
/* Wait till primary CPU is done with debugging */
while (atomic_read(&passive_cpu_wait[cpu]))
cpu_relax();
diff --git a/tools/perf/.gitignore b/tools/perf/.gitignore
index fe08660ce0b..124760bb37b 100644
--- a/tools/perf/.gitignore
+++ b/tools/perf/.gitignore
@@ -13,6 +13,7 @@ perf*.xml
perf*.html
common-cmds.h
perf.data
+perf.data.old
tags
TAGS
cscope*
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index db10c0e8eca..860f1eeeea7 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -269,7 +269,7 @@ parse_callchain_opt(const struct option *opt __used, const char *arg,
else if (!strncmp(tok, "none", strlen(arg))) {
callchain_param.mode = CHAIN_NONE;
- symbol_conf.use_callchain = true;
+ symbol_conf.use_callchain = false;
return 0;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-16 16:44:56 +0000