linux-kernel - [PATCH 1/6] x86: events: Avoid TIF

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Date:   Sat, 12 Sep 2020 03:05:48 -0400
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     luto@...nel.org, tglx@...utronix.de
Cc:     hpa@...or.com, bp@...en8.de, rric@...nel.org, peterz@...radead.org,
        mingo@...hat.com, x86@...nel.org, linux-kernel@...r.kernel.org,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        kernel@...labora.com
Subject: [PATCH 1/6] x86: events: Avoid TIF_IA32 when checking 64bit mode

In preparation to remove TIF_IA32, stop using it in perf events code.

Tested by running perf on 32-bit, 64-bit and x32 applications.

Suggested-by: Andy Lutomirski <luto@...nel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
 arch/x86/events/core.c      | 2 +-
 arch/x86/events/intel/ds.c  | 2 +-
 arch/x86/events/intel/lbr.c | 2 +-
 arch/x86/kernel/perf_regs.c | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 1cbf57dc2ac8..4fe82d9d959b 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2499,7 +2499,7 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry_ctx *ent
 	struct stack_frame_ia32 frame;
 	const struct stack_frame_ia32 __user *fp;
 
-	if (!test_thread_flag(TIF_IA32))
+	if (user_64bit_mode(regs))
 		return 0;
 
 	cs_base = get_segment_base(regs->cs);
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 86848c57b55e..94bd0d3acd15 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1261,7 +1261,7 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
 		old_to = to;
 
 #ifdef CONFIG_X86_64
-		is_64bit = kernel_ip(to) || !test_thread_flag(TIF_IA32);
+		is_64bit = kernel_ip(to) || any_64bit_mode(regs);
 #endif
 		insn_init(&insn, kaddr, size, is_64bit);
 		insn_get_length(&insn);
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 8961653c5dd2..1aadb253d296 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1221,7 +1221,7 @@ 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) || any_64bit_mode(current_pt_regs());
 #endif
 	insn_init(&insn, addr, bytes_read, is64);
 	insn_get_opcode(&insn);
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index bb7e1132290b..9332c49a64a8 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -123,7 +123,7 @@ int perf_reg_validate(u64 mask)
 
 u64 perf_reg_abi(struct task_struct *task)
 {
-	if (test_tsk_thread_flag(task, TIF_IA32))
+	if (!user_64bit_mode(task_pt_regs(task)))
 		return PERF_SAMPLE_REGS_ABI_32;
 	else
 		return PERF_SAMPLE_REGS_ABI_64;
-- 
2.28.0