x86, bts: provide in-kernel branch-trace interface
Impact: cleanup
Move the BTS bits from ptrace.c into ds.c.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index b2998fe..45e9855 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -581,153 +581,73 @@
}
#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 inline unsigned long bts_get(const char *base, enum bts_field field)
-{
- 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;
-}
-
-/*
- * 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, size_t index,
struct bts_struct __user *out)
{
- struct bts_struct ret;
- const void *bts_record;
- size_t bts_index, bts_end;
+ const struct bts_trace *trace;
+ struct bts_struct bts;
+ const unsigned char *at;
int error;
- error = ds_get_bts_end(child->bts, &bts_end);
+ trace = ds_read_bts(child->bts);
+ if (!trace)
+ return -EPERM;
+
+ at = trace->ds.top - ((index + 1) * trace->ds.size);
+ if ((void *)at < trace->ds.begin)
+ at += (trace->ds.n * trace->ds.size);
+
+ if (!trace->read)
+ return -EOPNOTSUPP;
+
+ error = trace->read(child->bts, at, &bts);
if (error < 0)
return error;
- if (bts_end <= index)
- return -EINVAL;
-
- error = ds_get_bts_index(child->bts, &bts_index);
- if (error < 0)
- return error;
-
- /* translate the ptrace bts index into the ds bts index */
- bts_index += bts_end - (index + 1);
- if (bts_end <= bts_index)
- bts_index -= bts_end;
-
- error = ds_access_bts(child->bts, bts_index, &bts_record);
- if (error < 0)
- return error;
-
- ptrace_bts_translate_record(&ret, bts_record);
-
- if (copy_to_user(out, &ret, sizeof(ret)))
+ if (copy_to_user(out, &bts, sizeof(bts)))
return -EFAULT;
- return sizeof(ret);
+ return sizeof(bts);
}
static int ptrace_bts_drain(struct task_struct *child,
long size,
struct bts_struct __user *out)
{
- struct bts_struct ret;
- const unsigned char *raw;
- size_t end, i;
- int error;
+ const struct bts_trace *trace;
+ const unsigned char *at;
+ int error, drained = 0;
- error = ds_get_bts_index(child->bts, &end);
- if (error < 0)
- return error;
+ trace = ds_read_bts(child->bts);
+ if (!trace)
+ return -EPERM;
- if (size < (end * sizeof(struct bts_struct)))
+ if (!trace->read)
+ return -EOPNOTSUPP;
+
+ if (size < (trace->ds.top - trace->ds.begin))
return -EIO;
- error = ds_access_bts(child->bts, 0, (const void **)&raw);
- if (error < 0)
- return error;
+ for (at = trace->ds.begin; (void *)at < trace->ds.top;
+ out++, drained++, at += trace->ds.size) {
+ struct bts_struct bts;
+ int error;
- for (i = 0; i < end; i++, out++, raw += bts_cfg.sizeof_bts) {
- ptrace_bts_translate_record(&ret, raw);
+ error = trace->read(child->bts, at, &bts);
+ if (error < 0)
+ return error;
- if (copy_to_user(out, &ret, sizeof(ret)))
+ if (copy_to_user(out, &bts, sizeof(bts)))
return -EFAULT;
}
- error = ds_clear_bts(child->bts);
+ memset(trace->ds.begin, 0, trace->ds.n * trace->ds.size);
+
+ error = ds_reset_bts(child->bts);
if (error < 0)
return error;
- return end;
+ return drained;
}
static int ptrace_bts_config(struct task_struct *child,
@@ -735,136 +655,89 @@
const struct ptrace_bts_config __user *ucfg)
{
struct ptrace_bts_config cfg;
- int error = 0;
+ unsigned int flags = 0;
- error = -EOPNOTSUPP;
- if (!bts_cfg.sizeof_bts)
- goto errout;
-
- error = -EIO;
if (cfg_size < sizeof(cfg))
- goto errout;
+ return -EIO;
- error = -EFAULT;
if (copy_from_user(&cfg, ucfg, sizeof(cfg)))
- goto errout;
+ return -EFAULT;
- error = -EINVAL;
- if ((cfg.flags & PTRACE_BTS_O_SIGNAL) &&
- !(cfg.flags & PTRACE_BTS_O_ALLOC))
- goto errout;
-
- if (cfg.flags & PTRACE_BTS_O_ALLOC) {
- bts_ovfl_callback_t ovfl = NULL;
- unsigned int sig = 0;
-
- error = -EINVAL;
- if (cfg.size < (10 * bts_cfg.sizeof_bts))
- goto errout;
-
- if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
- if (!cfg.signal)
- goto errout;
-
- error = -EOPNOTSUPP;
- goto errout;
-
- sig = cfg.signal;
- }
-
- if (child->bts) {
- (void)ds_release_bts(child->bts);
- kfree(child->bts_buffer);
-
- child->bts = NULL;
- child->bts_buffer = NULL;
- }
-
- error = -ENOMEM;
- child->bts_buffer = kzalloc(cfg.size, GFP_KERNEL);
- if (!child->bts_buffer)
- goto errout;
-
- child->bts = ds_request_bts(child, child->bts_buffer, cfg.size,
- ovfl, /* th = */ (size_t)-1);
- if (IS_ERR(child->bts)) {
- error = PTR_ERR(child->bts);
- kfree(child->bts_buffer);
- child->bts = NULL;
- child->bts_buffer = NULL;
- goto errout;
- }
-
- child->thread.bts_ovfl_signal = sig;
+ if (child->bts) {
+ ds_release_bts(child->bts);
+ child->bts = NULL;
}
- error = -EINVAL;
- if (!child->thread.ds_ctx && cfg.flags)
- goto errout;
+ if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
+ if (!cfg.signal)
+ return -EINVAL;
+
+ return -EOPNOTSUPP;
+
+ child->thread.bts_ovfl_signal = cfg.signal;
+ }
+
+ if ((cfg.flags & PTRACE_BTS_O_ALLOC) &&
+ (cfg.size != child->bts_size)) {
+ kfree(child->bts_buffer);
+
+ child->bts_size = cfg.size;
+ child->bts_buffer = kzalloc(cfg.size, GFP_KERNEL);
+ if (!child->bts_buffer) {
+ child->bts_size = 0;
+ return -ENOMEM;
+ }
+ }
if (cfg.flags & PTRACE_BTS_O_TRACE)
- child->thread.debugctlmsr |= bts_cfg.debugctl_mask;
- else
- child->thread.debugctlmsr &= ~bts_cfg.debugctl_mask;
+ flags |= BTS_USER;
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);
+ flags |= BTS_TIMESTAMPS;
- error = sizeof(cfg);
+ child->bts = ds_request_bts(child, child->bts_buffer, child->bts_size,
+ /* ovfl = */ NULL, /* th = */ (size_t)-1,
+ flags);
+ if (IS_ERR(child->bts)) {
+ int error = PTR_ERR(child->bts);
-out:
- if (child->thread.debugctlmsr)
- set_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
- else
- clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
+ kfree(child->bts_buffer);
+ child->bts = NULL;
+ child->bts_buffer = NULL;
+ child->bts_size = 0;
- return error;
+ return error;
+ }
-errout:
- child->thread.debugctlmsr &= ~bts_cfg.debugctl_mask;
- clear_tsk_thread_flag(child, TIF_BTS_TRACE_TS);
- goto out;
+ return sizeof(cfg);
}
static int ptrace_bts_status(struct task_struct *child,
long cfg_size,
struct ptrace_bts_config __user *ucfg)
{
+ const struct bts_trace *trace;
struct ptrace_bts_config cfg;
- size_t end;
- const void *base, *max;
- int error;
if (cfg_size < sizeof(cfg))
return -EIO;
- error = ds_get_bts_end(child->bts, &end);
- if (error < 0)
- return error;
-
- error = ds_access_bts(child->bts, /* index = */ 0, &base);
- if (error < 0)
- return error;
-
- error = ds_access_bts(child->bts, /* index = */ end, &max);
- if (error < 0)
- return error;
+ trace = ds_read_bts(child->bts);
+ if (!trace)
+ return -EPERM;
memset(&cfg, 0, sizeof(cfg));
- cfg.size = (max - base);
+ cfg.size = trace->ds.end - trace->ds.begin;
cfg.signal = child->thread.bts_ovfl_signal;
cfg.bts_size = sizeof(struct bts_struct);
if (cfg.signal)
cfg.flags |= PTRACE_BTS_O_SIGNAL;
- if (test_tsk_thread_flag(child, TIF_DEBUGCTLMSR) &&
- child->thread.debugctlmsr & bts_cfg.debugctl_mask)
+ if (trace->ds.flags & BTS_USER)
cfg.flags |= PTRACE_BTS_O_TRACE;
- if (test_tsk_thread_flag(child, TIF_BTS_TRACE_TS))
+ if (trace->ds.flags & BTS_TIMESTAMPS)
cfg.flags |= PTRACE_BTS_O_SCHED;
if (copy_to_user(ucfg, &cfg, sizeof(cfg)))
@@ -873,105 +746,28 @@
return sizeof(cfg);
}
-static int ptrace_bts_write_record(struct task_struct *child,
- const struct bts_struct *in)
+static int ptrace_bts_clear(struct task_struct *child)
{
- unsigned char bts_record[BTS_MAX_RECORD_SIZE];
+ const struct bts_trace *trace;
- if (BTS_MAX_RECORD_SIZE < bts_cfg.sizeof_bts)
- return -EOVERFLOW;
+ trace = ds_read_bts(child->bts);
+ if (!trace)
+ return -EPERM;
- memset(bts_record, 0, bts_cfg.sizeof_bts);
- switch (in->qualifier) {
- case BTS_INVALID:
- break;
+ memset(trace->ds.begin, 0, trace->ds.n * trace->ds.size);
- 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;
-
- 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;
-
- default:
- return -EINVAL;
- }
-
- return ds_write_bts(child->bts, bts_record, bts_cfg.sizeof_bts);
+ return ds_reset_bts(child->bts);
}
-void ptrace_bts_take_timestamp(struct task_struct *tsk,
- enum bts_qualifier qualifier)
+static int ptrace_bts_size(struct task_struct *child)
{
- struct bts_struct rec = {
- .qualifier = qualifier,
- .variant.jiffies = jiffies_64
- };
+ const struct bts_trace *trace;
- ptrace_bts_write_record(tsk, &rec);
-}
+ trace = ds_read_bts(child->bts);
+ if (!trace)
+ return -EPERM;
-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 0 ... 0xC:
- /* sorry, don't know about them */
- break;
- case 0xD:
- case 0xE: /* Pentium M */
- bts_configure(&bts_cfg_pentium_m);
- break;
- default: /* Core2, Atom, ... */
- bts_configure(&bts_cfg_core2);
- 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;
- }
+ return (trace->ds.top - trace->ds.begin) / trace->ds.size;
}
#endif /* CONFIG_X86_PTRACE_BTS */
@@ -988,15 +784,12 @@
#endif
#ifdef CONFIG_X86_PTRACE_BTS
if (child->bts) {
- (void)ds_release_bts(child->bts);
+ ds_release_bts(child->bts);
+ child->bts = NULL;
+
kfree(child->bts_buffer);
child->bts_buffer = NULL;
-
- 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);
+ child->bts_size = 0;
}
#endif /* CONFIG_X86_PTRACE_BTS */
}
@@ -1129,16 +922,9 @@
(child, data, (struct ptrace_bts_config __user *)addr);
break;
- case PTRACE_BTS_SIZE: {
- size_t size;
-
- ret = ds_get_bts_index(child->bts, &size);
- if (ret == 0) {
- WARN_ON_ONCE(size != (int) size);
- ret = (int) size;
- }
+ case PTRACE_BTS_SIZE:
+ ret = ptrace_bts_size(child);
break;
- }
case PTRACE_BTS_GET:
ret = ptrace_bts_read_record
@@ -1146,7 +932,7 @@
break;
case PTRACE_BTS_CLEAR:
- ret = ds_clear_bts(child->bts);
+ ret = ptrace_bts_clear(child);
break;
case PTRACE_BTS_DRAIN:
@@ -1409,6 +1195,14 @@
case PTRACE_GET_THREAD_AREA:
case PTRACE_SET_THREAD_AREA:
+#ifdef CONFIG_X86_PTRACE_BTS
+ case PTRACE_BTS_CONFIG:
+ case PTRACE_BTS_STATUS:
+ case PTRACE_BTS_SIZE:
+ case PTRACE_BTS_GET:
+ case PTRACE_BTS_CLEAR:
+ case PTRACE_BTS_DRAIN:
+#endif /* CONFIG_X86_PTRACE_BTS */
return arch_ptrace(child, request, addr, data);
default:
