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 <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

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index b6c6468e10bc96625c25c4ae8d19b734af81366b..4c8440de33559942a98245cf123a5ed10a30e406 100644 (file)
--- 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 c832291d948a6b4fd487a3e42fab8b8f7b9dd244..7cb8ba08beb997ef66724e2db5e66021c5ce32ee 100644 (file)
--- 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