Commit-ID:  cafa890653f4a4ba87e98b53d9c301260a4864b7
Gitweb:     https://git.kernel.org/tip/cafa890653f4a4ba87e98b53d9c301260a4864b7
Author:     David Woodhouse <[email protected]>
AuthorDate: Tue, 9 Jan 2018 14:43:12 +0000
Committer:  Thomas Gleixner <[email protected]>
CommitDate: Wed, 10 Jan 2018 18:28:23 +0100

x86/retpoline/ftrace: Convert ftrace assembler indirect jumps

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

Signed-off-by: David Woodhouse <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Arjan van de Ven <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Cc: [email protected]
Cc: Rik van Riel <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Paul Turner <[email protected]>
Link: 
https://lkml.kernel.org/r/[email protected]


---
 arch/x86/kernel/ftrace_32.S | 6 ++++--
 arch/x86/kernel/ftrace_64.S | 8 ++++----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index b6c6468..4c8440d 100644
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -8,6 +8,7 @@
 #include <asm/segment.h>
 #include <asm/export.h>
 #include <asm/ftrace.h>
+#include <asm/nospec-branch.h>
 
 #ifdef CC_USING_FENTRY
 # define function_hook __fentry__
@@ -197,7 +198,8 @@ ftrace_stub:
        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
@@ -241,5 +243,5 @@ return_to_handler:
        movl    %eax, %ecx
        popl    %edx
        popl    %eax
-       jmp     *%ecx
+       JMP_NOSPEC %ecx
 #endif
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index c832291..7cb8ba0 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -7,7 +7,7 @@
 #include <asm/ptrace.h>
 #include <asm/ftrace.h>
 #include <asm/export.h>
-
+#include <asm/nospec-branch.h>
 
        .code64
        .section .entry.text, "ax"
@@ -286,8 +286,8 @@ trace:
         * ip and parent ip are used and the list function is called when
         * function tracing is enabled.
         */
-       call   *ftrace_trace_function
-
+       movq ftrace_trace_function, %r8
+       CALL_NOSPEC %r8
        restore_mcount_regs
 
        jmp fgraph_trace
@@ -329,5 +329,5 @@ GLOBAL(return_to_handler)
        movq 8(%rsp), %rdx
        movq (%rsp), %rax
        addq $24, %rsp
-       jmp *%rdi
+       JMP_NOSPEC %rdi
 #endif

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