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 tools: Makefile: Use gcc to determine ARCH
  perf events, x86: Fix Intel Nehalem and Westmere last level cache event definitions
  hw_breakpoints, powerpc: Fix CONFIG_HAVE_HW_BREAKPOINT off-case in ptrace_set_debugreg()
  sh, hw_breakpoints: Fix racy access to ptrace breakpoints
  arm, hw_breakpoints: Fix racy access to ptrace breakpoints
  powerpc, hw_breakpoints: Fix racy access to ptrace breakpoints
  x86, hw_breakpoints: Fix racy access to ptrace breakpoints
  ptrace: Prepare to fix racy accesses on task breakpoints

10 files changed, 144 insertions, 54 deletions

diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 2bf27f364d09..8182f45ca493 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -767,12 +767,20 @@ long arch_ptrace(struct task_struct *child, long request,
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
                 case PTRACE_GETHBPREGS:
+                        if (ptrace_get_breakpoints(child) < 0)
+                                return -ESRCH;
+
                         ret = ptrace_gethbpregs(child, addr,
                                                 (unsigned long __user *)data);
+                        ptrace_put_breakpoints(child);
                         break;
                 case PTRACE_SETHBPREGS:
+                        if (ptrace_get_breakpoints(child) < 0)
+                                return -ESRCH;
+
                         ret = ptrace_sethbpregs(child, addr,
                                                 (unsigned long __user *)data);
+                        ptrace_put_breakpoints(child);
                         break;
 #endif
 
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 55613e33e263..a6ae1cfad86c 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -933,12 +933,16 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
         if (data && !(data & DABR_TRANSLATION))
                 return -EIO;
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
+        if (ptrace_get_breakpoints(task) < 0)
+                return -ESRCH;
+
         bp = thread->ptrace_bps[0];
         if ((!data) || !(data & (DABR_DATA_WRITE | DABR_DATA_READ))) {
                 if (bp) {
                         unregister_hw_breakpoint(bp);
                         thread->ptrace_bps[0] = NULL;
                 }
+                ptrace_put_breakpoints(task);
                 return 0;
         }
         if (bp) {
@@ -948,9 +952,12 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
                                         (DABR_DATA_WRITE | DABR_DATA_READ),
                                                         &attr.bp_type);
                 ret =  modify_user_hw_breakpoint(bp, &attr);
-                if (ret)
+                if (ret) {
+                        ptrace_put_breakpoints(task);
                         return ret;
+                }
                 thread->ptrace_bps[0] = bp;
+                ptrace_put_breakpoints(task);
                 thread->dabr = data;
                 return 0;
         }
@@ -965,9 +972,12 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
                                                         ptrace_triggered, task);
         if (IS_ERR(bp)) {
                 thread->ptrace_bps[0] = NULL;
+                ptrace_put_breakpoints(task);
                 return PTR_ERR(bp);
         }
 
+        ptrace_put_breakpoints(task);
+
 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 
         /* Move contents to the DABR register */
diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c
index 2130ca674e9b..3d7b209b2178 100644
--- a/arch/sh/kernel/ptrace_32.c
+++ b/arch/sh/kernel/ptrace_32.c
@@ -117,7 +117,11 @@ void user_enable_single_step(struct task_struct *child)
 
         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 
+        if (ptrace_get_breakpoints(child) < 0)
+                return;
+
         set_single_step(child, pc);
+        ptrace_put_breakpoints(child);
 }
 
 void user_disable_single_step(struct task_struct *child)
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index e61539b07d2c..447a28de6f09 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -184,26 +184,23 @@ static __initconst const u64 snb_hw_cache_event_ids
         },
  },
  [ C(LL  ) ] = {
-        /*
-         * TBD: Need Off-core Response Performance Monitoring support
-         */
         [ C(OP_READ) ] = {
-                /* OFFCORE_RESPONSE_0.ANY_DATA.LOCAL_CACHE */
+                /* OFFCORE_RESPONSE.ANY_DATA.LOCAL_CACHE */
                 [ C(RESULT_ACCESS) ] = 0x01b7,
-                /* OFFCORE_RESPONSE_1.ANY_DATA.ANY_LLC_MISS */
-                [ C(RESULT_MISS)   ] = 0x01bb,
+                /* OFFCORE_RESPONSE.ANY_DATA.ANY_LLC_MISS */
+                [ C(RESULT_MISS)   ] = 0x01b7,
         },
         [ C(OP_WRITE) ] = {
-                /* OFFCORE_RESPONSE_0.ANY_RFO.LOCAL_CACHE */
+                /* OFFCORE_RESPONSE.ANY_RFO.LOCAL_CACHE */
                 [ C(RESULT_ACCESS) ] = 0x01b7,
-                /* OFFCORE_RESPONSE_1.ANY_RFO.ANY_LLC_MISS */
-                [ C(RESULT_MISS)   ] = 0x01bb,
+                /* OFFCORE_RESPONSE.ANY_RFO.ANY_LLC_MISS */
+                [ C(RESULT_MISS)   ] = 0x01b7,
         },
         [ C(OP_PREFETCH) ] = {
-                /* OFFCORE_RESPONSE_0.PREFETCH.LOCAL_CACHE */
+                /* OFFCORE_RESPONSE.PREFETCH.LOCAL_CACHE */
                 [ C(RESULT_ACCESS) ] = 0x01b7,
-                /* OFFCORE_RESPONSE_1.PREFETCH.ANY_LLC_MISS */
-                [ C(RESULT_MISS)   ] = 0x01bb,
+                /* OFFCORE_RESPONSE.PREFETCH.ANY_LLC_MISS */
+                [ C(RESULT_MISS)   ] = 0x01b7,
         },
  },
  [ C(DTLB) ] = {
@@ -285,26 +282,26 @@ static __initconst const u64 westmere_hw_cache_event_ids
  },
  [ C(LL  ) ] = {
         [ C(OP_READ) ] = {
-                /* OFFCORE_RESPONSE_0.ANY_DATA.LOCAL_CACHE */
+                /* OFFCORE_RESPONSE.ANY_DATA.LOCAL_CACHE */
                 [ C(RESULT_ACCESS) ] = 0x01b7,
-                /* OFFCORE_RESPONSE_1.ANY_DATA.ANY_LLC_MISS */
-                [ C(RESULT_MISS)   ] = 0x01bb,
+                /* OFFCORE_RESPONSE.ANY_DATA.ANY_LLC_MISS */
+                [ C(RESULT_MISS)   ] = 0x01b7,
         },
         /*
          * Use RFO, not WRITEBACK, because a write miss would typically occur
          * on RFO.
          */
         [ C(OP_WRITE) ] = {
-                /* OFFCORE_RESPONSE_1.ANY_RFO.LOCAL_CACHE */
-                [ C(RESULT_ACCESS) ] = 0x01bb,
-                /* OFFCORE_RESPONSE_0.ANY_RFO.ANY_LLC_MISS */
+                /* OFFCORE_RESPONSE.ANY_RFO.LOCAL_CACHE */
+                [ C(RESULT_ACCESS) ] = 0x01b7,
+                /* OFFCORE_RESPONSE.ANY_RFO.ANY_LLC_MISS */
                 [ C(RESULT_MISS)   ] = 0x01b7,
         },
         [ C(OP_PREFETCH) ] = {
-                /* OFFCORE_RESPONSE_0.PREFETCH.LOCAL_CACHE */
+                /* OFFCORE_RESPONSE.PREFETCH.LOCAL_CACHE */
                 [ C(RESULT_ACCESS) ] = 0x01b7,
-                /* OFFCORE_RESPONSE_1.PREFETCH.ANY_LLC_MISS */
-                [ C(RESULT_MISS)   ] = 0x01bb,
+                /* OFFCORE_RESPONSE.PREFETCH.ANY_LLC_MISS */
+                [ C(RESULT_MISS)   ] = 0x01b7,
         },
  },
  [ C(DTLB) ] = {
@@ -352,16 +349,36 @@ static __initconst const u64 westmere_hw_cache_event_ids
 };
 
 /*
- * OFFCORE_RESPONSE MSR bits (subset), See IA32 SDM Vol 3 30.6.1.3
+ * Nehalem/Westmere MSR_OFFCORE_RESPONSE bits;
+ * See IA32 SDM Vol 3B 30.6.1.3
  */
 
-#define DMND_DATA_RD     (1 << 0)
-#define DMND_RFO         (1 << 1)
-#define DMND_WB          (1 << 3)
-#define PF_DATA_RD       (1 << 4)
-#define PF_DATA_RFO      (1 << 5)
-#define RESP_UNCORE_HIT  (1 << 8)
-#define RESP_MISS        (0xf600) /* non uncore hit */
+#define NHM_DMND_DATA_RD        (1 << 0)
+#define NHM_DMND_RFO            (1 << 1)
+#define NHM_DMND_IFETCH         (1 << 2)
+#define NHM_DMND_WB             (1 << 3)
+#define NHM_PF_DATA_RD          (1 << 4)
+#define NHM_PF_DATA_RFO         (1 << 5)
+#define NHM_PF_IFETCH           (1 << 6)
+#define NHM_OFFCORE_OTHER       (1 << 7)
+#define NHM_UNCORE_HIT          (1 << 8)
+#define NHM_OTHER_CORE_HIT_SNP  (1 << 9)
+#define NHM_OTHER_CORE_HITM     (1 << 10)
+                                /* reserved */
+#define NHM_REMOTE_CACHE_FWD    (1 << 12)
+#define NHM_REMOTE_DRAM         (1 << 13)
+#define NHM_LOCAL_DRAM          (1 << 14)
+#define NHM_NON_DRAM            (1 << 15)
+
+#define NHM_ALL_DRAM            (NHM_REMOTE_DRAM|NHM_LOCAL_DRAM)
+
+#define NHM_DMND_READ           (NHM_DMND_DATA_RD)
+#define NHM_DMND_WRITE          (NHM_DMND_RFO|NHM_DMND_WB)
+#define NHM_DMND_PREFETCH       (NHM_PF_DATA_RD|NHM_PF_DATA_RFO)
+
+#define NHM_L3_HIT      (NHM_UNCORE_HIT|NHM_OTHER_CORE_HIT_SNP|NHM_OTHER_CORE_HITM)
+#define NHM_L3_MISS     (NHM_NON_DRAM|NHM_ALL_DRAM|NHM_REMOTE_CACHE_FWD)
+#define NHM_L3_ACCESS   (NHM_L3_HIT|NHM_L3_MISS)
 
 static __initconst const u64 nehalem_hw_cache_extra_regs
                                 [PERF_COUNT_HW_CACHE_MAX]
@@ -370,16 +387,16 @@ static __initconst const u64 nehalem_hw_cache_extra_regs
 {
  [ C(LL  ) ] = {
         [ C(OP_READ) ] = {
-                [ C(RESULT_ACCESS) ] = DMND_DATA_RD|RESP_UNCORE_HIT,
-                [ C(RESULT_MISS)   ] = DMND_DATA_RD|RESP_MISS,
+                [ C(RESULT_ACCESS) ] = NHM_DMND_READ|NHM_L3_ACCESS,
+                [ C(RESULT_MISS)   ] = NHM_DMND_READ|NHM_L3_MISS,
         },
         [ C(OP_WRITE) ] = {
-                [ C(RESULT_ACCESS) ] = DMND_RFO|DMND_WB|RESP_UNCORE_HIT,
-                [ C(RESULT_MISS)   ] = DMND_RFO|DMND_WB|RESP_MISS,
+                [ C(RESULT_ACCESS) ] = NHM_DMND_WRITE|NHM_L3_ACCESS,
+                [ C(RESULT_MISS)   ] = NHM_DMND_WRITE|NHM_L3_MISS,
         },
         [ C(OP_PREFETCH) ] = {
-                [ C(RESULT_ACCESS) ] = PF_DATA_RD|PF_DATA_RFO|RESP_UNCORE_HIT,
-                [ C(RESULT_MISS)   ] = PF_DATA_RD|PF_DATA_RFO|RESP_MISS,
+                [ C(RESULT_ACCESS) ] = NHM_DMND_PREFETCH|NHM_L3_ACCESS,
+                [ C(RESULT_MISS)   ] = NHM_DMND_PREFETCH|NHM_L3_MISS,
         },
  }
 };
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 45892dc4b72a..f65e5b521dbd 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -608,6 +608,9 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
         unsigned len, type;
         struct perf_event *bp;
 
+        if (ptrace_get_breakpoints(tsk) < 0)
+                return -ESRCH;
+
         data &= ~DR_CONTROL_RESERVED;
         old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
 restore:
@@ -655,6 +658,9 @@ restore:
                 }
                 goto restore;
         }
+
+        ptrace_put_breakpoints(tsk);
+
         return ((orig_ret < 0) ? orig_ret : rc);
 }
 
@@ -668,10 +674,17 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
 
         if (n < HBP_NUM) {
                 struct perf_event *bp;
+
+                if (ptrace_get_breakpoints(tsk) < 0)
+                        return -ESRCH;
+
                 bp = thread->ptrace_bps[n];
                 if (!bp)
-                        return 0;
-                val = bp->hw.info.address;
+                        val = 0;
+                else
+                        val = bp->hw.info.address;
+
+                ptrace_put_breakpoints(tsk);
         } else if (n == 6) {
                 val = thread->debugreg6;
          } else if (n == 7) {
@@ -686,6 +699,10 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
         struct perf_event *bp;
         struct thread_struct *t = &tsk->thread;
         struct perf_event_attr attr;
+        int err = 0;
+
+        if (ptrace_get_breakpoints(tsk) < 0)
+                return -ESRCH;
 
         if (!t->ptrace_bps[nr]) {
                 ptrace_breakpoint_init(&attr);
@@ -709,24 +726,23 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
                  * writing for the user. And anyway this is the previous
                  * behaviour.
                  */
-                if (IS_ERR(bp))
-                        return PTR_ERR(bp);
+                if (IS_ERR(bp)) {
+                        err = PTR_ERR(bp);
+                        goto put;
+                }
 
                 t->ptrace_bps[nr] = bp;
         } else {
-                int err;
-
                 bp = t->ptrace_bps[nr];
 
                 attr = bp->attr;
                 attr.bp_addr = addr;
                 err = modify_user_hw_breakpoint(bp, &attr);
-                if (err)
-                        return err;
         }
 
-
-        return 0;
+put:
+        ptrace_put_breakpoints(tsk);
+        return err;
 }
 
 /*
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index a1147e5dd245..9178d5cc0b01 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -189,6 +189,10 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
                 child->ptrace = current->ptrace;
                 __ptrace_link(child, current->parent);
         }
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+        atomic_set(&child->ptrace_bp_refcnt, 1);
+#endif
 }
 
 /**
@@ -350,6 +354,13 @@ extern int task_current_syscall(struct task_struct *target, long *callno,
                                 unsigned long args[6], unsigned int maxargs,
                                 unsigned long *sp, unsigned long *pc);
 
-#endif
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+extern int ptrace_get_breakpoints(struct task_struct *tsk);
+extern void ptrace_put_breakpoints(struct task_struct *tsk);
+#else
+static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
+#endif /* __KERNEL */
 
 #endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 18d63cea2848..781abd137673 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1537,6 +1537,9 @@ struct task_struct {
                 unsigned long memsw_nr_pages; /* uncharged mem+swap usage */
         } memcg_batch;
 #endif
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+        atomic_t ptrace_bp_refcnt;
+#endif
 };
 
 /* Future-safe accessor for struct task_struct's cpus_allowed. */
diff --git a/kernel/exit.c b/kernel/exit.c
index f5d2f63bae0b..8dd874181542 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1016,7 +1016,7 @@ NORET_TYPE void do_exit(long code)
         /*
          * FIXME: do that only when needed, using sched_exit tracepoint
          */
-        flush_ptrace_hw_breakpoint(tsk);
+        ptrace_put_breakpoints(tsk);
 
         exit_notify(tsk, group_dead);
 #ifdef CONFIG_NUMA
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 0fc1eed28d27..dc7ab65f3b36 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -22,6 +22,7 @@
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <linux/regset.h>
+#include <linux/hw_breakpoint.h>
 
 
 /*
@@ -879,3 +880,19 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
         return ret;
 }
 #endif  /* CONFIG_COMPAT */
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+int ptrace_get_breakpoints(struct task_struct *tsk)
+{
+        if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt))
+                return 0;
+
+        return -1;
+}
+
+void ptrace_put_breakpoints(struct task_struct *tsk)
+{
+        if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt))
+                flush_ptrace_hw_breakpoint(tsk);
+}
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 207dee5c5b16..0c542563ea6c 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -35,15 +35,21 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
                                   -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
                                   -e s/sh[234].*/sh/ )
 
+CC = $(CROSS_COMPILE)gcc
+AR = $(CROSS_COMPILE)ar
+
 # Additional ARCH settings for x86
 ifeq ($(ARCH),i386)
         ARCH := x86
 endif
 ifeq ($(ARCH),x86_64)
-        RAW_ARCH := x86_64
-        ARCH := x86
-        ARCH_CFLAGS := -DARCH_X86_64
-        ARCH_INCLUDE = ../../arch/x86/lib/memcpy_64.S
+        ARCH := x86
+        IS_X86_64 := $(shell echo __x86_64__ | ${CC} -E -xc - | tail -n 1)
+        ifeq (${IS_X86_64}, 1)
+                RAW_ARCH := x86_64
+                ARCH_CFLAGS := -DARCH_X86_64
+                ARCH_INCLUDE = ../../arch/x86/lib/memcpy_64.S
+        endif
 endif
 
 #
@@ -119,8 +125,6 @@ lib = lib
 
 export prefix bindir sharedir sysconfdir
 
-CC = $(CROSS_COMPILE)gcc
-AR = $(CROSS_COMPILE)ar
 RM = rm -f
 MKDIR = mkdir
 FIND = find