Commit 834db333 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-fixes-for-linus' of... 

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf, hw_breakpoint, kgdb: Do not take mutex for kernel debugger
  x86, hw_breakpoints, kgdb: Fix kgdb to use hw_breakpoint API
  hw_breakpoints: Release the bp slot if arch_validate_hwbkpt_settings() fails.
  perf: Ignore perf.data.old
  perf report: Fix segmentation fault when running with '-g none'
parents 8ea85c28 5352ae63

arch/x86/kernel/kgdb.c

+165 −57
Original line number Diff line number Diff line
@@ -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);

		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;



		} else {

			if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {

				correctit = 1;

				dr7 &= ~breakbit;

				dr7 &= ~(0xf0000 << (breakno << 2));

	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);

	}

	return -1;

}

	if (correctit)

		set_debugreg(dr7, 7);



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;

		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);

}

include/linux/hw_breakpoint.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

kernel/hw_breakpoint.c

+46 −10
Original line number Diff line number Diff line
@@ -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;

}

kernel/kgdb.c

+3 −0
Original line number Diff line number Diff line
@@ -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();

tools/perf/.gitignore

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ perf*.xml 
perf*.html

common-cmds.h

perf.data

perf.data.old

tags

TAGS

cscope*

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