17 files changed, 175 insertions, 32 deletions

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index dab39350e51e..cb4e43bce98a 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -196,11 +196,16 @@ static inline u32 get_ibs_caps(void) { return 0; }
 extern void perf_events_lapic_init(void);
 
 /*
- * Abuse bit 3 of the cpu eflags register to indicate proper PEBS IP fixups.
- * This flag is otherwise unused and ABI specified to be 0, so nobody should
- * care what we do with it.
+ * Abuse bits {3,5} of the cpu eflags register. These flags are otherwise
+ * unused and ABI specified to be 0, so nobody should care what we do with
+ * them.
+ *
+ * EXACT - the IP points to the exact instruction that triggered the
+ *         event (HW bugs exempt).
+ * VM    - original X86_VM_MASK; see set_linear_ip().
  */
 #define PERF_EFLAGS_EXACT       (1UL << 3)
+#define PERF_EFLAGS_VM          (1UL << 5)
 
 struct pt_regs;
 extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 29557aa06dda..915b876edd1e 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -32,6 +32,8 @@
 #include <asm/smp.h>
 #include <asm/alternative.h>
 #include <asm/timer.h>
+#include <asm/desc.h>
+#include <asm/ldt.h>
 
 #include "perf_event.h"
 
@@ -1738,6 +1740,29 @@ valid_user_frame(const void __user *fp, unsigned long size)
         return (__range_not_ok(fp, size, TASK_SIZE) == 0);
 }
 
+static unsigned long get_segment_base(unsigned int segment)
+{
+        struct desc_struct *desc;
+        int idx = segment >> 3;
+
+        if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) {
+                if (idx > LDT_ENTRIES)
+                        return 0;
+
+                if (idx > current->active_mm->context.size)
+                        return 0;
+
+                desc = current->active_mm->context.ldt;
+        } else {
+                if (idx > GDT_ENTRIES)
+                        return 0;
+
+                desc = __this_cpu_ptr(&gdt_page.gdt[0]);
+        }
+
+        return get_desc_base(desc + idx);
+}
+
 #ifdef CONFIG_COMPAT
 
 #include <asm/compat.h>
@@ -1746,13 +1771,17 @@ static inline int
 perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
 {
         /* 32-bit process in 64-bit kernel. */
+        unsigned long ss_base, cs_base;
         struct stack_frame_ia32 frame;
         const void __user *fp;
 
         if (!test_thread_flag(TIF_IA32))
                 return 0;
 
-        fp = compat_ptr(regs->bp);
+        cs_base = get_segment_base(regs->cs);
+        ss_base = get_segment_base(regs->ss);
+
+        fp = compat_ptr(ss_base + regs->bp);
         while (entry->nr < PERF_MAX_STACK_DEPTH) {
                 unsigned long bytes;
                 frame.next_frame     = 0;
@@ -1765,8 +1794,8 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
                 if (!valid_user_frame(fp, sizeof(frame)))
                         break;
 
-                perf_callchain_store(entry, frame.return_address);
-                fp = compat_ptr(frame.next_frame);
+                perf_callchain_store(entry, cs_base + frame.return_address);
+                fp = compat_ptr(ss_base + frame.next_frame);
         }
         return 1;
 }
@@ -1789,6 +1818,12 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
                 return;
         }
 
+        /*
+         * We don't know what to do with VM86 stacks.. ignore them for now.
+         */
+        if (regs->flags & (X86_VM_MASK | PERF_EFLAGS_VM))
+                return;
+
         fp = (void __user *)regs->bp;
 
         perf_callchain_store(entry, regs->ip);
@@ -1816,16 +1851,50 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
         }
 }
 
-unsigned long perf_instruction_pointer(struct pt_regs *regs)
+/*
+ * Deal with code segment offsets for the various execution modes:
+ *
+ *   VM86 - the good olde 16 bit days, where the linear address is
+ *          20 bits and we use regs->ip + 0x10 * regs->cs.
+ *
+ *   IA32 - Where we need to look at GDT/LDT segment descriptor tables
+ *          to figure out what the 32bit base address is.
+ *
+ *    X32 - has TIF_X32 set, but is running in x86_64
+ *
+ * X86_64 - CS,DS,SS,ES are all zero based.
+ */
+static unsigned long code_segment_base(struct pt_regs *regs)
 {
-        unsigned long ip;
+        /*
+         * If we are in VM86 mode, add the segment offset to convert to a
+         * linear address.
+         */
+        if (regs->flags & X86_VM_MASK)
+                return 0x10 * regs->cs;
+
+        /*
+         * For IA32 we look at the GDT/LDT segment base to convert the
+         * effective IP to a linear address.
+         */
+#ifdef CONFIG_X86_32
+        if (user_mode(regs) && regs->cs != __USER_CS)
+                return get_segment_base(regs->cs);
+#else
+        if (test_thread_flag(TIF_IA32)) {
+                if (user_mode(regs) && regs->cs != __USER32_CS)
+                        return get_segment_base(regs->cs);
+        }
+#endif
+        return 0;
+}
 
+unsigned long perf_instruction_pointer(struct pt_regs *regs)
+{
         if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
-                ip = perf_guest_cbs->get_guest_ip();
-        else
-                ip = instruction_pointer(regs);
+                return perf_guest_cbs->get_guest_ip();
 
-        return ip;
+        return regs->ip + code_segment_base(regs);
 }
 
 unsigned long perf_misc_flags(struct pt_regs *regs)
@@ -1838,7 +1907,7 @@ unsigned long perf_misc_flags(struct pt_regs *regs)
                 else
                         misc |= PERF_RECORD_MISC_GUEST_KERNEL;
         } else {
-                if (!kernel_ip(regs->ip))
+                if (user_mode(regs))
                         misc |= PERF_RECORD_MISC_USER;
                 else
                         misc |= PERF_RECORD_MISC_KERNEL;
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 821d53b696d1..6605a81ba339 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -516,6 +516,26 @@ static inline bool kernel_ip(unsigned long ip)
 #endif
 }
 
+/*
+ * Not all PMUs provide the right context information to place the reported IP
+ * into full context. Specifically segment registers are typically not
+ * supplied.
+ *
+ * Assuming the address is a linear address (it is for IBS), we fake the CS and
+ * vm86 mode using the known zero-based code segment and 'fix up' the registers
+ * to reflect this.
+ *
+ * Intel PEBS/LBR appear to typically provide the effective address, nothing
+ * much we can do about that but pray and treat it like a linear address.
+ */
+static inline void set_linear_ip(struct pt_regs *regs, unsigned long ip)
+{
+        regs->cs = kernel_ip(ip) ? __KERNEL_CS : __USER_CS;
+        if (regs->flags & X86_VM_MASK)
+                regs->flags ^= (PERF_EFLAGS_VM | X86_VM_MASK);
+        regs->ip = ip;
+}
+
 #ifdef CONFIG_CPU_SUP_AMD
 
 int amd_pmu_init(void);
diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index da9bcdcd9856..7bfb5bec8630 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -13,6 +13,8 @@
 
 #include <asm/apic.h>
 
+#include "perf_event.h"
+
 static u32 ibs_caps;
 
 #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD)
@@ -536,7 +538,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
         if (check_rip && (ibs_data.regs[2] & IBS_RIP_INVALID)) {
                 regs.flags &= ~PERF_EFLAGS_EXACT;
         } else {
-                instruction_pointer_set(&regs, ibs_data.regs[1]);
+                set_linear_ip(&regs, ibs_data.regs[1]);
                 regs.flags |= PERF_EFLAGS_EXACT;
         }
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 629ae0b7ad90..e38d97bf4259 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -499,7 +499,7 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
          * We sampled a branch insn, rewind using the LBR stack
          */
         if (ip == to) {
-                regs->ip = from;
+                set_linear_ip(regs, from);
                 return 1;
         }
 
@@ -529,7 +529,7 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
         } while (to < ip);
 
         if (to == ip) {
-                regs->ip = old_to;
+                set_linear_ip(regs, old_to);
                 return 1;
         }
 
@@ -569,7 +569,8 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
          * A possible PERF_SAMPLE_REGS will have to transfer all regs.
          */
         regs = *iregs;
-        regs.ip = pebs->ip;
+        regs.flags = pebs->flags;
+        set_linear_ip(&regs, pebs->ip);
         regs.bp = pebs->bp;
         regs.sp = pebs->sp;
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.h b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
index f3851892e077..c9e5dc56630a 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.h
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
@@ -5,7 +5,7 @@
 #include "perf_event.h"
 
 #define UNCORE_PMU_NAME_LEN             32
-#define UNCORE_PMU_HRTIMER_INTERVAL     (60 * NSEC_PER_SEC)
+#define UNCORE_PMU_HRTIMER_INTERVAL     (60LL * NSEC_PER_SEC)
 
 #define UNCORE_FIXED_EVENT              0xff
 #define UNCORE_PMC_IDX_MAX_GENERIC      8
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index af961d6f7ab1..642928cf57b4 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -306,9 +306,10 @@ extern void *perf_trace_buf_prepare(int size, unsigned short type,
 
 static inline void
 perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
-                       u64 count, struct pt_regs *regs, void *head)
+                       u64 count, struct pt_regs *regs, void *head,
+                       struct task_struct *task)
 {
-        perf_tp_event(addr, count, raw_data, size, regs, head, rctx);
+        perf_tp_event(addr, count, raw_data, size, regs, head, rctx, task);
 }
 #endif
 
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 76c5c8b724a7..7602ccb3f40e 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1272,7 +1272,8 @@ static inline bool perf_paranoid_kernel(void)
 extern void perf_event_init(void);
 extern void perf_tp_event(u64 addr, u64 count, void *record,
                           int entry_size, struct pt_regs *regs,
-                          struct hlist_head *head, int rctx);
+                          struct hlist_head *head, int rctx,
+                          struct task_struct *task);
 extern void perf_bp_event(struct perf_event *event, void *data);
 
 #ifndef perf_misc_flags
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index ea7a2035456d..5a8671e8a67f 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -73,6 +73,9 @@ DECLARE_EVENT_CLASS(sched_wakeup_template,
                 __entry->prio           = p->prio;
                 __entry->success        = success;
                 __entry->target_cpu     = task_cpu(p);
+        )
+        TP_perf_assign(
+                __perf_task(p);
         ),
 
         TP_printk("comm=%s pid=%d prio=%d success=%d target_cpu=%03d",
@@ -325,6 +328,7 @@ DECLARE_EVENT_CLASS(sched_stat_template,
         )
         TP_perf_assign(
                 __perf_count(delay);
+                __perf_task(tsk);
         ),
 
         TP_printk("comm=%s pid=%d delay=%Lu [ns]",
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index c6bc2faaf261..a763888a36f9 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -712,6 +712,9 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
 #undef __perf_count
 #define __perf_count(c) __count = (c)
 
+#undef __perf_task
+#define __perf_task(t) __task = (t)
+
 #undef TP_perf_assign
 #define TP_perf_assign(args...) args
 
@@ -725,6 +728,7 @@ perf_trace_##call(void *__data, proto)					\
         struct ftrace_raw_##call *entry;                                \
         struct pt_regs __regs;                                          \
         u64 __addr = 0, __count = 1;                                    \
+        struct task_struct *__task = NULL;                              \
         struct hlist_head *head;                                        \
         int __entry_size;                                               \
         int __data_size;                                                \
@@ -752,7 +756,7 @@ perf_trace_##call(void *__data, proto)					\
                                                                         \
         head = this_cpu_ptr(event_call->perf_events);                   \
         perf_trace_buf_submit(entry, __entry_size, rctx, __addr,        \
-                __count, &__regs, head);                                \
+                __count, &__regs, head, __task);                        \
 }
 
 /*
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 6581a040f399..98d4597f43d6 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -153,7 +153,8 @@ put_callchain_entry(int rctx)
         put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
 }
 
-struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
+struct perf_callchain_entry *
+perf_callchain(struct perf_event *event, struct pt_regs *regs)
 {
         int rctx;
         struct perf_callchain_entry *entry;
@@ -178,6 +179,12 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
         }
 
         if (regs) {
+                /*
+                 * Disallow cross-task user callchains.
+                 */
+                if (event->ctx->task && event->ctx->task != current)
+                        goto exit_put;
+
                 perf_callchain_store(entry, PERF_CONTEXT_USER);
                 perf_callchain_user(entry, regs);
         }
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f1cf0edeb39a..b7935fcec7d9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4039,7 +4039,7 @@ void perf_prepare_sample(struct perf_event_header *header,
         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
                 int size = 1;
 
-                data->callchain = perf_callchain(regs);
+                data->callchain = perf_callchain(event, regs);
 
                 if (data->callchain)
                         size += data->callchain->nr;
@@ -5209,7 +5209,8 @@ static int perf_tp_event_match(struct perf_event *event,
 }
 
 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
-                   struct pt_regs *regs, struct hlist_head *head, int rctx)
+                   struct pt_regs *regs, struct hlist_head *head, int rctx,
+                   struct task_struct *task)
 {
         struct perf_sample_data data;
         struct perf_event *event;
@@ -5228,6 +5229,31 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
                         perf_swevent_event(event, count, &data, regs);
         }
 
+        /*
+         * If we got specified a target task, also iterate its context and
+         * deliver this event there too.
+         */
+        if (task && task != current) {
+                struct perf_event_context *ctx;
+                struct trace_entry *entry = record;
+
+                rcu_read_lock();
+                ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
+                if (!ctx)
+                        goto unlock;
+
+                list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+                        if (event->attr.type != PERF_TYPE_TRACEPOINT)
+                                continue;
+                        if (event->attr.config != entry->type)
+                                continue;
+                        if (perf_tp_event_match(event, &data, regs))
+                                perf_swevent_event(event, count, &data, regs);
+                }
+unlock:
+                rcu_read_unlock();
+        }
+
         perf_swevent_put_recursion_context(rctx);
 }
 EXPORT_SYMBOL_GPL(perf_tp_event);
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index b0b107f90afc..a096c19f2c2a 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -101,7 +101,8 @@ __output_copy(struct perf_output_handle *handle,
 }
 
 /* Callchain handling */
-extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
+extern struct perf_callchain_entry *
+perf_callchain(struct perf_event *event, struct pt_regs *regs);
 extern int get_callchain_buffers(void);
 extern void put_callchain_buffers(void);
 
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index fee3752ae8f6..8a6d2ee2086c 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -281,7 +281,7 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip)
 
         head = this_cpu_ptr(event_function.perf_events);
         perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0,
-                              1, &regs, head);
+                              1, &regs, head, NULL);
 
 #undef ENTRY_SIZE
 }
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index b31d3d5699fe..1a2117043bb1 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1002,7 +1002,8 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
         head = this_cpu_ptr(call->perf_events);
-        perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
+        perf_trace_buf_submit(entry, size, rctx,
+                                        entry->ip, 1, regs, head, NULL);
 }
 
 /* Kretprobe profile handler */
@@ -1033,7 +1034,8 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
         head = this_cpu_ptr(call->perf_events);
-        perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
+        perf_trace_buf_submit(entry, size, rctx,
+                                        entry->ret_ip, 1, regs, head, NULL);
 }
 #endif  /* CONFIG_PERF_EVENTS */
 
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 96fc73369099..60e4d7875672 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -532,7 +532,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
                                (unsigned long *)&rec->args);
 
         head = this_cpu_ptr(sys_data->enter_event->perf_events);
-        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
+        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
 int perf_sysenter_enable(struct ftrace_event_call *call)
@@ -608,7 +608,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
         rec->ret = syscall_get_return_value(current, regs);
 
         head = this_cpu_ptr(sys_data->exit_event->perf_events);
-        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
+        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
 int perf_sysexit_enable(struct ftrace_event_call *call)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 2b36ac68549e..03003cd7dd96 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -670,7 +670,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 
         head = this_cpu_ptr(call->perf_events);
-        perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
+        perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL);
 
  out:
         preempt_enable();