1 files changed, 269 insertions, 175 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index e37dccce85d..5df6093ac77 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -554,45 +554,115 @@ static int ptrace_set_debugreg(struct task_struct *child,
 	return 0;
 }
 
-#ifdef X86_BTS
+#ifdef CONFIG_X86_PTRACE_BTS
+/*
+ * The configuration for a particular BTS hardware implementation.
+ */
+struct bts_configuration {
+	/* the size of a BTS record in bytes; at most BTS_MAX_RECORD_SIZE */
+	unsigned char  sizeof_bts;
+	/* the size of a field in the BTS record in bytes */
+	unsigned char  sizeof_field;
+	/* a bitmask to enable/disable BTS in DEBUGCTL MSR */
+	unsigned long debugctl_mask;
+};
+static struct bts_configuration bts_cfg;
+
+#define BTS_MAX_RECORD_SIZE (8 * 3)
+
+
+/*
+ * Branch Trace Store (BTS) uses the following format. Different
+ * architectures vary in the size of those fields.
+ * - source linear address
+ * - destination linear address
+ * - flags
+ *
+ * Later architectures use 64bit pointers throughout, whereas earlier
+ * architectures use 32bit pointers in 32bit mode.
+ *
+ * We compute the base address for the first 8 fields based on:
+ * - the field size stored in the DS configuration
+ * - the relative field position
+ *
+ * In order to store additional information in the BTS buffer, we use
+ * a special source address to indicate that the record requires
+ * special interpretation.
+ *
+ * Netburst indicated via a bit in the flags field whether the branch
+ * was predicted; this is ignored.
+ */
+
+enum bts_field {
+	bts_from = 0,
+	bts_to,
+	bts_flags,
+
+	bts_escape = (unsigned long)-1,
+	bts_qual = bts_to,
+	bts_jiffies = bts_flags
+};
 
-static int ptrace_bts_get_size(struct task_struct *child)
+static inline unsigned long bts_get(const char *base, enum bts_field field)
 {
-	if (!child->thread.ds_area_msr)
-		return -ENXIO;
+	base += (bts_cfg.sizeof_field * field);
+	return *(unsigned long *)base;
+}
+
+static inline void bts_set(char *base, enum bts_field field, unsigned long val)
+{
+	base += (bts_cfg.sizeof_field * field);;
+	(*(unsigned long *)base) = val;
+}
 
-	return ds_get_bts_index((void *)child->thread.ds_area_msr);
+/*
+ * Translate a BTS record from the raw format into the bts_struct format
+ *
+ * out (out): bts_struct interpretation
+ * raw: raw BTS record
+ */
+static void ptrace_bts_translate_record(struct bts_struct *out, const void *raw)
+{
+	memset(out, 0, sizeof(*out));
+	if (bts_get(raw, bts_from) == bts_escape) {
+		out->qualifier       = bts_get(raw, bts_qual);
+		out->variant.jiffies = bts_get(raw, bts_jiffies);
+	} else {
+		out->qualifier = BTS_BRANCH;
+		out->variant.lbr.from_ip = bts_get(raw, bts_from);
+		out->variant.lbr.to_ip   = bts_get(raw, bts_to);
+	}
 }
 
-static int ptrace_bts_read_record(struct task_struct *child,
-				  long index,
+static int ptrace_bts_read_record(struct task_struct *child, size_t index,
 				  struct bts_struct __user *out)
 {
 	struct bts_struct ret;
-	int retval;
-	int bts_end;
-	int bts_index;
+	const void *bts_record;
+	size_t bts_index, bts_end;
+	int error;
 
-	if (!child->thread.ds_area_msr)
-		return -ENXIO;
+	error = ds_get_bts_end(child, &bts_end);
+	if (error < 0)
+		return error;
 
-	if (index < 0)
-		return -EINVAL;
-
-	bts_end = ds_get_bts_end((void *)child->thread.ds_area_msr);
 	if (bts_end <= index)
 		return -EINVAL;
 
+	error = ds_get_bts_index(child, &bts_index);
+	if (error < 0)
+		return error;
+
 	/* translate the ptrace bts index into the ds bts index */
-	bts_index = ds_get_bts_index((void *)child->thread.ds_area_msr);
-	bts_index -= (index + 1);
-	if (bts_index < 0)
-		bts_index += bts_end;
+	bts_index += bts_end - (index + 1);
+	if (bts_end <= bts_index)
+		bts_index -= bts_end;
+
+	error = ds_access_bts(child, bts_index, &bts_record);
+	if (error < 0)
+		return error;
 
-	retval = ds_read_bts((void *)child->thread.ds_area_msr,
-			     bts_index, &ret);
-	if (retval < 0)
-		return retval;
+	ptrace_bts_translate_record(&ret, bts_record);
 
 	if (copy_to_user(out, &ret, sizeof(ret)))
 		return -EFAULT;
@@ -600,101 +670,106 @@ static int ptrace_bts_read_record(struct task_struct *child,
 	return sizeof(ret);
 }
 
-static int ptrace_bts_clear(struct task_struct *child)
-{
-	if (!child->thread.ds_area_msr)
-		return -ENXIO;
-
-	return ds_clear((void *)child->thread.ds_area_msr);
-}
-
 static int ptrace_bts_drain(struct task_struct *child,
 			    long size,
 			    struct bts_struct __user *out)
 {
-	int end, i;
-	void *ds = (void *)child->thread.ds_area_msr;
-
-	if (!ds)
-		return -ENXIO;
+	struct bts_struct ret;
+	const unsigned char *raw;
+	size_t end, i;
+	int error;
 
-	end = ds_get_bts_index(ds);
-	if (end <= 0)
-		return end;
+	error = ds_get_bts_index(child, &end);
+	if (error < 0)
+		return error;
 
 	if (size < (end * sizeof(struct bts_struct)))
 		return -EIO;
 
-	for (i = 0; i < end; i++, out++) {
-		struct bts_struct ret;
-		int retval;
+	error = ds_access_bts(child, 0, (const void **)&raw);
+	if (error < 0)
+		return error;
 
-		retval = ds_read_bts(ds, i, &ret);
-		if (retval < 0)
-			return retval;
+	for (i = 0; i < end; i++, out++, raw += bts_cfg.sizeof_bts) {
+		ptrace_bts_translate_record(&ret, raw);
 
 		if (copy_to_user(out, &ret, sizeof(ret)))
 			return -EFAULT;
 	}
 
-	ds_clear(ds);
+	error = ds_clear_bts(child);
+	if (error < 0)
+		return error;
 
 	return end;
 }
 
+static void ptrace_bts_ovfl(struct task_struct *child)
+{
+	send_sig(child->thread.bts_ovfl_signal, child, 0);
+}
+
 static int ptrace_bts_config(struct task_struct *child,
 			     long cfg_size,
 			     const struct ptrace_bts_config __user *ucfg)
 {
 	struct ptrace_bts_config cfg;
-	int bts_size, ret = 0;
-	void *ds;
+	int error = 0;
+
+	error = -EOPNOTSUPP;
+	if (!bts_cfg.sizeof_bts)
+		goto errout;
 
+	error = -EIO;
 	if (cfg_size < sizeof(cfg))
-		return -EIO;
+		goto errout;
 
+	error = -EFAULT;
 	if (copy_from_user(&cfg, ucfg, sizeof(cfg)))
-		return -EFAULT;
+		goto errout;
 
-	if ((int)cfg.size < 0)
-		return -EINVAL;
+	error = -EINVAL;
+	if ((cfg.flags & PTRACE_BTS_O_SIGNAL) &&
+	    !(cfg.flags & PTRACE_BTS_O_ALLOC))
+		goto errout;
 
-	bts_size = 0;
-	ds = (void *)child->thread.ds_area_msr;
-	if (ds) {
-		bts_size = ds_get_bts_size(ds);
-		if (bts_size < 0)
-			return bts_size;
-	}
-	cfg.size = PAGE_ALIGN(cfg.size);
+	if (cfg.flags & PTRACE_BTS_O_ALLOC) {
+		ds_ovfl_callback_t ovfl = NULL;
+		unsigned int sig = 0;
+
+		/* we ignore the error in case we were not tracing child */
+		(void)ds_release_bts(child);
+
+		if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
+			if (!cfg.signal)
+				goto errout;
+
+			sig  = cfg.signal;
+			ovfl = ptrace_bts_ovfl;
+		}
 
-	if (bts_size != cfg.size) {
-		ret = ptrace_bts_realloc(child, cfg.size,
-					 cfg.flags & PTRACE_BTS_O_CUT_SIZE);
-		if (ret < 0)
+		error = ds_request_bts(child, /* base = */ NULL, cfg.size, ovfl);
+		if (error < 0)
 			goto errout;
 
-		ds = (void *)child->thread.ds_area_msr;
+		child->thread.bts_ovfl_signal = sig;
 	}
 
-	if (cfg.flags & PTRACE_BTS_O_SIGNAL)
-		ret = ds_set_overflow(ds, DS_O_SIGNAL);
-	else
-		ret = ds_set_overflow(ds, DS_O_WRAP);
-	if (ret < 0)
+	error = -EINVAL;
+	if (!child->thread.ds_ctx && cfg.flags)
 		goto errout;
 
 	if (cfg.flags & PTRACE_BTS_O_TRACE)
-		child->thread.debugctlmsr |= ds_debugctl_mask();
+		child->thread.debugctlmsr |= bts_cfg.debugctl_mask;
 	else
-		child->thread.debugctlmsr &= ~ds_debugctl_mask();
+		child->thread.debugctlmsr &= ~bts_cfg.debugctl_mask;
 
 	if (cfg.flags & PTRACE_BTS_O_SCHED)
 		set_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
 	else
 		clear_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
 
-	ret = sizeof(cfg);
+	error = sizeof(cfg);
 
 out:
 	if (child->thread.debugctlmsr)
@@ -702,10 +777,10 @@ out:
 	else
 		clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
 
-	return ret;
+	return error;
 
 errout:
-	child->thread.debugctlmsr &= ~ds_debugctl_mask();
+	child->thread.debugctlmsr &= ~bts_cfg.debugctl_mask;
 	clear_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
 	goto out;
 }
@@ -714,29 +789,40 @@ static int ptrace_bts_status(struct task_struct *child,
 			     long cfg_size,
 			     struct ptrace_bts_config __user *ucfg)
 {
-	void *ds = (void *)child->thread.ds_area_msr;
 	struct ptrace_bts_config cfg;
+	size_t end;
+	const void *base, *max;
+	int error;
 
 	if (cfg_size < sizeof(cfg))
 		return -EIO;
 
-	memset(&cfg, 0, sizeof(cfg));
+	error = ds_get_bts_end(child, &end);
+	if (error < 0)
+		return error;
 
-	if (ds) {
-		cfg.size = ds_get_bts_size(ds);
+	error = ds_access_bts(child, /* index = */ 0, &base);
+	if (error < 0)
+		return error;
 
-		if (ds_get_overflow(ds) == DS_O_SIGNAL)
-			cfg.flags |= PTRACE_BTS_O_SIGNAL;
+	error = ds_access_bts(child, /* index = */ end, &max);
+	if (error < 0)
+		return error;
 
-		if (test_tsk_thread_flag(child, TIF_DEBUGCTLMSR) &&
-		    child->thread.debugctlmsr & ds_debugctl_mask())
-			cfg.flags |= PTRACE_BTS_O_TRACE;
+	memset(&cfg, 0, sizeof(cfg));
+	cfg.size = (max - base);
+	cfg.signal = child->thread.bts_ovfl_signal;
+	cfg.bts_size = sizeof(struct bts_struct);
 
-		if (test_tsk_thread_flag(child, TIF_BTS_TRACE_TS))
-			cfg.flags |= PTRACE_BTS_O_SCHED;
-	}
+	if (cfg.signal)
+		cfg.flags |= PTRACE_BTS_O_SIGNAL;
 
-	cfg.bts_size = sizeof(struct bts_struct);
+	if (test_tsk_thread_flag(child, TIF_DEBUGCTLMSR) &&
+	    child->thread.debugctlmsr & bts_cfg.debugctl_mask)
+		cfg.flags |= PTRACE_BTS_O_TRACE;
+
+	if (test_tsk_thread_flag(child, TIF_BTS_TRACE_TS))
+		cfg.flags |= PTRACE_BTS_O_SCHED;
 
 	if (copy_to_user(ucfg, &cfg, sizeof(cfg)))
 		return -EFAULT;
@@ -744,89 +830,38 @@ static int ptrace_bts_status(struct task_struct *child,
 	return sizeof(cfg);
 }
 
-
 static int ptrace_bts_write_record(struct task_struct *child,
 				   const struct bts_struct *in)
 {
-	int retval;
+	unsigned char bts_record[BTS_MAX_RECORD_SIZE];
 
-	if (!child->thread.ds_area_msr)
-		return -ENXIO;
+	BUG_ON(BTS_MAX_RECORD_SIZE < bts_cfg.sizeof_bts);
 
-	retval = ds_write_bts((void *)child->thread.ds_area_msr, in);
-	if (retval)
-		return retval;
+	memset(bts_record, 0, bts_cfg.sizeof_bts);
+	switch (in->qualifier) {
+	case BTS_INVALID:
+		break;
 
-	return sizeof(*in);
-}
+	case BTS_BRANCH:
+		bts_set(bts_record, bts_from, in->variant.lbr.from_ip);
+		bts_set(bts_record, bts_to,   in->variant.lbr.to_ip);
+		break;
 
-static int ptrace_bts_realloc(struct task_struct *child,
-			      int size, int reduce_size)
-{
-	unsigned long rlim, vm;
-	int ret, old_size;
+	case BTS_TASK_ARRIVES:
+	case BTS_TASK_DEPARTS:
+		bts_set(bts_record, bts_from,    bts_escape);
+		bts_set(bts_record, bts_qual,    in->qualifier);
+		bts_set(bts_record, bts_jiffies, in->variant.jiffies);
+		break;
 
-	if (size < 0)
+	default:
 		return -EINVAL;
-
-	old_size = ds_get_bts_size((void *)child->thread.ds_area_msr);
-	if (old_size < 0)
-		return old_size;
-
-	ret = ds_free((void **)&child->thread.ds_area_msr);
-	if (ret < 0)
-		goto out;
-
-	size >>= PAGE_SHIFT;
-	old_size >>= PAGE_SHIFT;
-
-	current->mm->total_vm  -= old_size;
-	current->mm->locked_vm -= old_size;
-
-	if (size == 0)
-		goto out;
-
-	rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
-	vm = current->mm->total_vm  + size;
-	if (rlim < vm) {
-		ret = -ENOMEM;
-
-		if (!reduce_size)
-			goto out;
-
-		size = rlim - current->mm->total_vm;
-		if (size <= 0)
-			goto out;
 	}
 
-	rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
-	vm = current->mm->locked_vm  + size;
-	if (rlim < vm) {
-		ret = -ENOMEM;
-
-		if (!reduce_size)
-			goto out;
-
-		size = rlim - current->mm->locked_vm;
-		if (size <= 0)
-			goto out;
-	}
-
-	ret = ds_allocate((void **)&child->thread.ds_area_msr,
-			  size << PAGE_SHIFT);
-	if (ret < 0)
-		goto out;
-
-	current->mm->total_vm  += size;
-	current->mm->locked_vm += size;
-
-out:
-	if (child->thread.ds_area_msr)
-		set_tsk_thread_flag(child, TIF_DS_AREA_MSR);
-	else
-		clear_tsk_thread_flag(child, TIF_DS_AREA_MSR);
-
-	return ret;
+	/* The writing task will be the switched-to task on a context
+	 * switch. It needs to write into the switched-from task's BTS
+	 * buffer. */
+	return ds_unchecked_write_bts(child, bts_record, bts_cfg.sizeof_bts);
 }
 
 void ptrace_bts_take_timestamp(struct task_struct *tsk,
@@ -839,7 +874,66 @@ void ptrace_bts_take_timestamp(struct task_struct *tsk,
 
 	ptrace_bts_write_record(tsk, &rec);
 }
-#endif /* X86_BTS */
+
+static const struct bts_configuration bts_cfg_netburst = {
+	.sizeof_bts    = sizeof(long) * 3,
+	.sizeof_field  = sizeof(long),
+	.debugctl_mask = (1<<2)|(1<<3)|(1<<5)
+};
+
+static const struct bts_configuration bts_cfg_pentium_m = {
+	.sizeof_bts    = sizeof(long) * 3,
+	.sizeof_field  = sizeof(long),
+	.debugctl_mask = (1<<6)|(1<<7)
+};
+
+static const struct bts_configuration bts_cfg_core2 = {
+	.sizeof_bts    = 8 * 3,
+	.sizeof_field  = 8,
+	.debugctl_mask = (1<<6)|(1<<7)|(1<<9)
+};
+
+static inline void bts_configure(const struct bts_configuration *cfg)
+{
+	bts_cfg = *cfg;
+}
+
+void __cpuinit ptrace_bts_init_intel(struct cpuinfo_x86 *c)
+{
+	switch (c->x86) {
+	case 0x6:
+		switch (c->x86_model) {
+		case 0xD:
+		case 0xE: /* Pentium M */
+			bts_configure(&bts_cfg_pentium_m);
+			break;
+		case 0xF: /* Core2 */
+        case 0x1C: /* Atom */
+			bts_configure(&bts_cfg_core2);
+			break;
+		default:
+			/* sorry, don't know about them */
+			break;
+		}
+		break;
+	case 0xF:
+		switch (c->x86_model) {
+		case 0x0:
+		case 0x1:
+		case 0x2: /* Netburst */
+			bts_configure(&bts_cfg_netburst);
+			break;
+		default:
+			/* sorry, don't know about them */
+			break;
+		}
+		break;
+	default:
+		/* sorry, don't know about them */
+		break;
+	}
+}
+#endif /* CONFIG_X86_PTRACE_BTS */
 
 /*
  * Called by kernel/ptrace.c when detaching..
@@ -852,15 +946,15 @@ void ptrace_disable(struct task_struct *child)
 #ifdef TIF_SYSCALL_EMU
 	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 #endif
-	if (child->thread.ds_area_msr) {
-#ifdef X86_BTS
-		ptrace_bts_realloc(child, 0, 0);
-#endif
-		child->thread.debugctlmsr &= ~ds_debugctl_mask();
-		if (!child->thread.debugctlmsr)
-			clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
-		clear_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
-	}
+#ifdef CONFIG_X86_PTRACE_BTS
+	(void)ds_release_bts(child);
+
+	child->thread.debugctlmsr &= ~bts_cfg.debugctl_mask;
+	if (!child->thread.debugctlmsr)
+		clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
+
+	clear_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
+#endif /* CONFIG_X86_PTRACE_BTS */
 }
 
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
@@ -980,7 +1074,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 	/*
 	 * These bits need more cooking - not enabled yet:
 	 */
-#ifdef X86_BTS
+#ifdef CONFIG_X86_PTRACE_BTS
 	case PTRACE_BTS_CONFIG:
 		ret = ptrace_bts_config
 			(child, data, (struct ptrace_bts_config __user *)addr);
@@ -992,7 +1086,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		break;
 
 	case PTRACE_BTS_SIZE:
-		ret = ptrace_bts_get_size(child);
+		ret = ds_get_bts_index(child, /* pos = */ NULL);
 		break;
 
 	case PTRACE_BTS_GET:
@@ -1001,14 +1095,14 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		break;
 
 	case PTRACE_BTS_CLEAR:
-		ret = ptrace_bts_clear(child);
+		ret = ds_clear_bts(child);
 		break;
 
 	case PTRACE_BTS_DRAIN:
 		ret = ptrace_bts_drain
 			(child, data, (struct bts_struct __user *) addr);
 		break;
-#endif
+#endif /* CONFIG_X86_PTRACE_BTS */
 
 	default:
 		ret = ptrace_request(child, request, addr, data);