linux-kernel - [tip:x86/pti] x86/retpoline/irq32: Convert assembler indirect jumps

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Message-ID: <tip-3025d1ebb41bc8fc58fc050c6d4d6dd4d71ca5e8@git.kernel.org>
Date:   Tue, 9 Jan 2018 07:59:17 -0800
From:   tip-bot for Andi Kleen <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     torvalds@...ux-foundation.org, riel@...hat.com,
        gregkh@...ux-foundation.org, linux-kernel@...r.kernel.org,
        pjt@...gle.com, tim.c.chen@...ux.intel.com, ak@...ux.intel.com,
        peterz@...radead.org, mingo@...nel.org, jikos@...nel.org,
        tglx@...utronix.de, hpa@...or.com, dave.hansen@...el.com,
        luto@...capital.net, arjan@...ux.intel.com, keescook@...gle.com
Subject: [tip:x86/pti] x86/retpoline/irq32: Convert assembler indirect jumps

Commit-ID:  3025d1ebb41bc8fc58fc050c6d4d6dd4d71ca5e8
Gitweb:     https://git.kernel.org/tip/3025d1ebb41bc8fc58fc050c6d4d6dd4d71ca5e8
Author:     Andi Kleen <ak@...ux.intel.com>
AuthorDate: Tue, 9 Jan 2018 14:43:16 +0000
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue, 9 Jan 2018 16:17:54 +0100

x86/retpoline/irq32: Convert assembler indirect jumps

Convert all indirect jumps in 32bit irq inline asm code to use non
speculative sequences.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Arjan van de Ven <arjan@...ux.intel.com>
Acked-by: Ingo Molnar <mingo@...nel.org>
Cc: gnomes@...rguk.ukuu.org.uk
Cc: Rik van Riel <riel@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Jiri Kosina <jikos@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Kees Cook <keescook@...gle.com>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@...ux-foundation.org>
Cc: Paul Turner <pjt@...gle.com>
Link: https://lkml.kernel.org/r/1515508997-6154-11-git-send-email-dwmw@amazon.co.uk

---
 arch/x86/kernel/irq_32.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index a83b334..c1bdbd3 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 
 #include <asm/apic.h>
+#include <asm/nospec-branch.h>
 
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 
@@ -55,11 +56,11 @@ DEFINE_PER_CPU(struct irq_stack *, softirq_stack);
 static void call_on_stack(void *func, void *stack)
 {
 	asm volatile("xchgl	%%ebx,%%esp	\n"
-		     "call	*%%edi		\n"
+		     CALL_NOSPEC
 		     "movl	%%ebx,%%esp	\n"
 		     : "=b" (stack)
 		     : "0" (stack),
-		       "D"(func)
+		       [thunk_target] "D"(func)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -95,11 +96,11 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		call_on_stack(print_stack_overflow, isp);
 
 	asm volatile("xchgl	%%ebx,%%esp	\n"
-		     "call	*%%edi		\n"
+		     CALL_NOSPEC
 		     "movl	%%ebx,%%esp	\n"
 		     : "=a" (arg1), "=b" (isp)
 		     :  "0" (desc),   "1" (isp),
-			"D" (desc->handle_irq)
+			[thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "ecx");
 	return 1;
 }