From e60dde1114399bbae104e49368b62cad6cb6b730 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw@amazon.co.uk>
Date: Thu, 11 Jan 2018 21:46:29 +0000
Subject: [PATCH] x86/retpoline/ftrace: Convert ftrace assembler indirect jumps

commit 9351803bd803cdbeb9b5a7850b7b6f464806e3db upstream.

Convert all indirect jumps in ftrace assembler code to use non-speculative
sequences when CONFIG_RETPOLINE is enabled.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: thomas.lendacky@amd.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-8-git-send-email-dwmw@amazon.co.uk
[bwh: Backported to 3.2: adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 arch/x86/kernel/entry_32.S | 5 +++--
 arch/x86/kernel/entry_64.S | 6 +++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 4859635f5d42..f3801c756c80 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1193,7 +1193,8 @@ trace:
 	movl 0x4(%ebp), %edx
 	subl $MCOUNT_INSN_SIZE, %eax
 
-	call *ftrace_trace_function
+	movl ftrace_trace_function, %ecx
+	CALL_NOSPEC %ecx
 
 	popl %edx
 	popl %ecx
@@ -1231,7 +1232,7 @@ return_to_handler:
 	movl %eax, %ecx
 	popl %edx
 	popl %eax
-	jmp *%ecx
+	JMP_NOSPEC %ecx
 #endif
 
 .section .rodata,"a"
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7e9d2ad4c47d..a2b14db26b8a 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -126,8 +126,8 @@ trace:
 	movq 8(%rbp), %rsi
 	subq $MCOUNT_INSN_SIZE, %rdi
 
-	call   *ftrace_trace_function
-
+	movq ftrace_trace_function, %r8
+	CALL_NOSPEC %r8
 	MCOUNT_RESTORE_FRAME
 
 	jmp ftrace_stub
@@ -168,7 +168,7 @@ GLOBAL(return_to_handler)
 	movq 8(%rsp), %rdx
 	movq (%rsp), %rax
 	addq $24, %rsp
-	jmp *%rdi
+	JMP_NOSPEC %rdi
 #endif
 
 
-- 
2.39.2