]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - arch/x86/kernel/ptrace.c
Merge branch 'x86/tracehook' into x86-v28-for-linus-phase1
[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / ptrace.c
index 19a7d2c40560f13b810409c141ccec23594d63ce..e375b658efc316e4e14785b7f2a3ad61e763cd82 100644 (file)
@@ -70,7 +70,7 @@ static inline bool invalid_selector(u16 value)
 
 #define FLAG_MASK              FLAG_MASK_32
 
-static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
+static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
 {
        BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
        regno >>= 2;
@@ -555,45 +555,115 @@ 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;
@@ -601,101 +671,106 @@ 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)
@@ -703,10 +778,10 @@ 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;
 }
@@ -715,29 +790,40 @@ 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;
@@ -745,89 +831,38 @@ 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,
@@ -840,7 +875,66 @@ 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..
@@ -853,15 +947,15 @@ 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
@@ -981,7 +1075,7 @@ 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);
@@ -993,7 +1087,7 @@ 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:
@@ -1002,14 +1096,14 @@ 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);