linux-kernel - [PATCH 3/4] x86/intel lbr: down with test_thread_flag(TIF

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Message-ID: <1460657414-12530-4-git-send-email-dsafonov@virtuozzo.com>
Date:	Thu, 14 Apr 2016 21:10:13 +0300
From:	Dmitry Safonov <dsafonov@...tuozzo.com>
To:	<linux-kernel@...r.kernel.org>
CC:	<luto@...capital.net>, <tglx@...utronix.de>, <mingo@...hat.com>,
	<hpa@...or.com>, <x86@...nel.org>, <rric@...nel.org>,
	<oprofile-list@...ts.sf.net>, <0x7f454c46@...il.com>,
	Dmitry Safonov <dsafonov@...tuozzo.com>
Subject: [PATCH 3/4] x86/intel lbr: down with test_thread_flag(TIF_IA32)

Use user_mode64_bit to check process state. For that pass
interrupt register set from irq handler.
This should fix opcode decoder misinterpreting ABI for
tasks that change their code selector.

Signed-off-by: Dmitry Safonov <dsafonov@...tuozzo.com>
---
 arch/x86/events/intel/core.c |  2 +-
 arch/x86/events/intel/lbr.c  | 17 ++++++++++-------
 arch/x86/events/perf_event.h |  2 +-
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 68fa55b4d42e..df13d1d6dbf6 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -1860,7 +1860,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 
 	loops = 0;
 again:
-	intel_pmu_lbr_read();
+	intel_pmu_lbr_read(regs);
 	intel_pmu_ack_status(status);
 	if (++loops > 100) {
 		static bool warned = false;
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 6c3b7c1780c9..f1a1dbc77dea 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -136,7 +136,9 @@ enum {
 	 X86_BR_IRQ		|\
 	 X86_BR_INT)
 
-static void intel_pmu_lbr_filter(struct cpu_hw_events *cpuc);
+
+static void
+intel_pmu_lbr_filter(struct pt_regs *regs, struct cpu_hw_events *cpuc);
 
 /*
  * We only support LBR implementations that have FREEZE_LBRS_ON_PMI
@@ -500,7 +502,7 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
 	cpuc->lbr_stack.nr = out;
 }
 
-void intel_pmu_lbr_read(void)
+void intel_pmu_lbr_read(struct pt_regs *regs)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 
@@ -512,7 +514,7 @@ void intel_pmu_lbr_read(void)
 	else
 		intel_pmu_lbr_read_64(cpuc);
 
-	intel_pmu_lbr_filter(cpuc);
+	intel_pmu_lbr_filter(regs, cpuc);
 }
 
 /*
@@ -658,7 +660,8 @@ int intel_pmu_setup_lbr_filter(struct perf_event *event)
  * decoded (e.g., text page not present), then X86_BR_NONE is
  * returned.
  */
-static int branch_type(unsigned long from, unsigned long to, int abort)
+static int branch_type(unsigned long from, unsigned long to, int abort,
+		struct pt_regs *regs)
 {
 	struct insn insn;
 	void *addr;
@@ -724,7 +727,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
 	 * on 64-bit systems running 32-bit apps
 	 */
 #ifdef CONFIG_X86_64
-	is64 = kernel_ip((unsigned long)addr) || !test_thread_flag(TIF_IA32);
+	is64 = kernel_ip((unsigned long)addr) || user_64bit_mode(regs);
 #endif
 	insn_init(&insn, addr, bytes_read, is64);
 	insn_get_opcode(&insn);
@@ -830,7 +833,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
  * in PERF_SAMPLE_BRANCH_STACK sample may vary.
  */
 static void
-intel_pmu_lbr_filter(struct cpu_hw_events *cpuc)
+intel_pmu_lbr_filter(struct pt_regs *regs, struct cpu_hw_events *cpuc)
 {
 	u64 from, to;
 	int br_sel = cpuc->br_sel;
@@ -846,7 +849,7 @@ intel_pmu_lbr_filter(struct cpu_hw_events *cpuc)
 		from = cpuc->lbr_entries[i].from;
 		to = cpuc->lbr_entries[i].to;
 
-		type = branch_type(from, to, cpuc->lbr_entries[i].abort);
+		type = branch_type(from, to, cpuc->lbr_entries[i].abort, regs);
 		if (type != X86_BR_NONE && (br_sel & X86_BR_ANYTX)) {
 			if (cpuc->lbr_entries[i].in_tx)
 				type |= X86_BR_IN_TX;
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index ad4dc7ffffb5..da1ec8240097 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -899,7 +899,7 @@ void intel_pmu_lbr_enable_all(bool pmi);
 
 void intel_pmu_lbr_disable_all(void);
 
-void intel_pmu_lbr_read(void);
+void intel_pmu_lbr_read(struct pt_regs *regs);
 
 void intel_pmu_lbr_init_core(void);
 
-- 
2.8.0