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Date:   Tue, 05 May 2020 15:43:57 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, "Paul E. McKenney" <paulmck@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Alexandre Chartre <alexandre.chartre@...cle.com>,
        Frederic Weisbecker <frederic@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Brian Gerst <brgerst@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Will Deacon <will@...nel.org>
Subject: [patch V4 part 3 03/29] x86/entry: Disable interrupts for
 native_load_gs_index() in C code

There is absolutely no point in doing this in ASM code. Move it to C.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/entry/entry_64.S            |   19 +++++++------------
 arch/x86/include/asm/special_insns.h |   14 ++++++++++++--
 2 files changed, 19 insertions(+), 14 deletions(-)

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1036,27 +1036,22 @@ idtentry alignment_check		do_alignment_c
 idtentry simd_coprocessor_error		do_simd_coprocessor_error	has_error_code=0
 
 
-	/*
-	 * Reload gs selector with exception handling
-	 * edi:  new selector
-	 */
+/*
+ * Reload gs selector with exception handling
+ * edi:  new selector
+ */
 .pushsection .text, "ax"
-SYM_FUNC_START(native_load_gs_index)
+SYM_FUNC_START(asm_native_load_gs_index)
 	FRAME_BEGIN
-	pushfq
-	DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
-	TRACE_IRQS_OFF
 	SWAPGS
 .Lgs_change:
 	movl	%edi, %gs
 2:	ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
 	SWAPGS
-	TRACE_IRQS_FLAGS (%rsp)
-	popfq
 	FRAME_END
 	ret
-SYM_FUNC_END(native_load_gs_index)
-EXPORT_SYMBOL(native_load_gs_index)
+SYM_FUNC_END(asm_native_load_gs_index)
+EXPORT_SYMBOL(asm_native_load_gs_index)
 .popsection
 
 	_ASM_EXTABLE(.Lgs_change, .Lbad_gs)
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -7,6 +7,7 @@
 
 #include <asm/nops.h>
 #include <asm/processor-flags.h>
+#include <linux/irqflags.h>
 #include <linux/jump_label.h>
 
 /*
@@ -129,7 +130,16 @@ static inline void native_wbinvd(void)
 	asm volatile("wbinvd": : :"memory");
 }
 
-extern asmlinkage void native_load_gs_index(unsigned);
+extern asmlinkage void asm_native_load_gs_index(unsigned int selector);
+
+static inline void native_load_gs_index(unsigned int selector)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	asm_native_load_gs_index(selector);
+	local_irq_restore(flags);
+}
 
 static inline unsigned long __read_cr4(void)
 {
@@ -186,7 +196,7 @@ static inline void wbinvd(void)
 
 #ifdef CONFIG_X86_64
 
-static inline void load_gs_index(unsigned selector)
+static inline void load_gs_index(unsigned int selector)
 {
 	native_load_gs_index(selector);
 }

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