1 files changed, 152 insertions, 280 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 0a6d8c12e10d..0a5df5f82fb9 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -581,158 +581,91 @@ static int ioperm_get(struct task_struct *target,
 }
 
 #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_end);
-        if (error < 0)
-                return error;
-
-        if (bts_end <= index)
-                return -EINVAL;
+        trace = ds_read_bts(child->bts);
+        if (!trace)
+                return -EPERM;
 
-        error = ds_get_bts_index(child, &bts_index);
-        if (error < 0)
-                return error;
+        at = trace->ds.top - ((index + 1) * trace->ds.size);
+        if ((void *)at < trace->ds.begin)
+                at += (trace->ds.n * trace->ds.size);
 
-        /* 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;
+        if (!trace->read)
+                return -EOPNOTSUPP;
 
-        error = ds_access_bts(child, bts_index, &bts_record);
+        error = trace->read(child->bts, at, &bts);
         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, &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, 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);
+        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 void ptrace_bts_ovfl(struct task_struct *child)
+static int ptrace_bts_allocate_buffer(struct task_struct *child, size_t size)
 {
-        send_sig(child->thread.bts_ovfl_signal, child, 0);
+        child->bts_buffer = alloc_locked_buffer(size);
+        if (!child->bts_buffer)
+                return -ENOMEM;
+
+        child->bts_size = size;
+
+        return 0;
+}
+
+static void ptrace_bts_free_buffer(struct task_struct *child)
+{
+        free_locked_buffer(child->bts_buffer, child->bts_size);
+        child->bts_buffer = NULL;
+        child->bts_size = 0;
 }
 
 static int ptrace_bts_config(struct task_struct *child,
@@ -740,114 +673,86 @@ static int ptrace_bts_config(struct task_struct *child,
                              const struct ptrace_bts_config __user *ucfg)
 {
         struct ptrace_bts_config cfg;
-        int error = 0;
-
-        error = -EOPNOTSUPP;
-        if (!bts_cfg.sizeof_bts)
-                goto errout;
+        unsigned int flags = 0;
 
-        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 (child->bts) {
+                ds_release_bts(child->bts);
+                child->bts = NULL;
+        }
 
-        if (cfg.flags & PTRACE_BTS_O_ALLOC) {
-                ds_ovfl_callback_t ovfl = NULL;
-                unsigned int sig = 0;
+        if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
+                if (!cfg.signal)
+                        return -EINVAL;
 
-                /* we ignore the error in case we were not tracing child */
-                (void)ds_release_bts(child);
+                return -EOPNOTSUPP;
 
-                if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
-                        if (!cfg.signal)
-                                goto errout;
+                child->thread.bts_ovfl_signal = cfg.signal;
+        }
 
-                        sig  = cfg.signal;
-                        ovfl = ptrace_bts_ovfl;
-                }
+        if ((cfg.flags & PTRACE_BTS_O_ALLOC) &&
+            (cfg.size != child->bts_size)) {
+                int error;
 
-                error = ds_request_bts(child, /* base = */ NULL, cfg.size, ovfl);
-                if (error < 0)
-                        goto errout;
+                ptrace_bts_free_buffer(child);
 
-                child->thread.bts_ovfl_signal = sig;
+                error = ptrace_bts_allocate_buffer(child, cfg.size);
+                if (error < 0)
+                        return error;
         }
 
-        error = -EINVAL;
-        if (!child->thread.ds_ctx && cfg.flags)
-                goto errout;
-
         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);
+                ptrace_bts_free_buffer(child);
+                child->bts = NULL;
 
-        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, &end);
-        if (error < 0)
-                return error;
-
-        error = ds_access_bts(child, /* index = */ 0, &base);
-        if (error < 0)
-                return error;
-
-        error = ds_access_bts(child, /* 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)))
@@ -856,110 +761,77 @@ 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)
+static int ptrace_bts_clear(struct task_struct *child)
 {
-        unsigned char bts_record[BTS_MAX_RECORD_SIZE];
+        const struct bts_trace *trace;
 
-        BUG_ON(BTS_MAX_RECORD_SIZE < bts_cfg.sizeof_bts);
+        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;
+        return ds_reset_bts(child->bts);
+}
 
-        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;
+static int ptrace_bts_size(struct task_struct *child)
+{
+        const struct bts_trace *trace;
 
-        default:
-                return -EINVAL;
-        }
+        trace = ds_read_bts(child->bts);
+        if (!trace)
+                return -EPERM;
 
-        /* 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);
+        return (trace->ds.top - trace->ds.begin) / trace->ds.size;
 }
 
-void ptrace_bts_take_timestamp(struct task_struct *tsk,
-                               enum bts_qualifier qualifier)
+static void ptrace_bts_fork(struct task_struct *tsk)
 {
-        struct bts_struct rec = {
-                .qualifier = qualifier,
-                .variant.jiffies = jiffies_64
-        };
-
-        ptrace_bts_write_record(tsk, &rec);
+        tsk->bts = NULL;
+        tsk->bts_buffer = NULL;
+        tsk->bts_size = 0;
+        tsk->thread.bts_ovfl_signal = 0;
 }
 
-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 void ptrace_bts_untrace(struct task_struct *child)
+{
+        if (unlikely(child->bts)) {
+                ds_release_bts(child->bts);
+                child->bts = NULL;
+
+                /* We cannot update total_vm and locked_vm since
+                   child's mm is already gone. But we can reclaim the
+                   memory. */
+                kfree(child->bts_buffer);
+                child->bts_buffer = NULL;
+                child->bts_size = 0;
+        }
+}
 
-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 void ptrace_bts_detach(struct task_struct *child)
+{
+        if (unlikely(child->bts)) {
+                ds_release_bts(child->bts);
+                child->bts = NULL;
 
-static const struct bts_configuration bts_cfg_core2 = {
-        .sizeof_bts    = 8 * 3,
-        .sizeof_field  = 8,
-        .debugctl_mask = (1<<6)|(1<<7)|(1<<9)
-};
+                ptrace_bts_free_buffer(child);
+        }
+}
+#else
+static inline void ptrace_bts_fork(struct task_struct *tsk) {}
+static inline void ptrace_bts_detach(struct task_struct *child) {}
+static inline void ptrace_bts_untrace(struct task_struct *child) {}
+#endif /* CONFIG_X86_PTRACE_BTS */
 
-static inline void bts_configure(const struct bts_configuration *cfg)
+void x86_ptrace_fork(struct task_struct *child, unsigned long clone_flags)
 {
-        bts_cfg = *cfg;
+        ptrace_bts_fork(child);
 }
 
-void __cpuinit ptrace_bts_init_intel(struct cpuinfo_x86 *c)
+void x86_ptrace_untrace(struct task_struct *child)
 {
-        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;
-        }
+        ptrace_bts_untrace(child);
 }
-#endif /* CONFIG_X86_PTRACE_BTS */
 
 /*
  * Called by kernel/ptrace.c when detaching..
@@ -972,15 +844,7 @@ void ptrace_disable(struct task_struct *child)
 #ifdef TIF_SYSCALL_EMU
         clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 #endif
-#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 */
+        ptrace_bts_detach(child);
 }
 
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
@@ -1112,7 +976,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                 break;
 
         case PTRACE_BTS_SIZE:
-                ret = ds_get_bts_index(child, /* pos = */ NULL);
+                ret = ptrace_bts_size(child);
                 break;
 
         case PTRACE_BTS_GET:
@@ -1121,7 +985,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                 break;
 
         case PTRACE_BTS_CLEAR:
-                ret = ds_clear_bts(child);
+                ret = ptrace_bts_clear(child);
                 break;
 
         case PTRACE_BTS_DRAIN:
@@ -1384,6 +1248,14 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
         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: