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
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Razvan Ghitulete <rga@amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index adbbd4f538e96de9c09d6d634957567a64f9aa09..d437f3871e5322b2085ba3d3ba49d44b342bdf1c 100644 (file)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -863,7 +863,8 @@ 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
@@ -898,7 +899,7 @@ return_to_handler:
        movl    %eax, %ecx
        popl    %edx
        popl    %eax
-       jmp     *%ecx
+       JMP_NOSPEC %ecx
 #endif
 
 #ifdef CONFIG_TRACING

diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
index 5d9afbcb6074af4f4a26467a45d8d8e1087f68be..09284cfab86fb3f1cf26ee68335d5061e495a1dc 100644 (file)
--- a/arch/x86/kernel/mcount_64.S
+++ b/arch/x86/kernel/mcount_64.S
@@ -7,7 +7,7 @@
 #include <linux/linkage.h>
 #include <asm/ptrace.h>
 #include <asm/ftrace.h>
-
+#include <asm/nospec-branch.h>
 
        .code64
        .section .entry.text, "ax"
@@ -285,8 +285,9 @@ 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 +330,5 @@ GLOBAL(return_to_handler)
        movq 8(%rsp), %rdx
        movq (%rsp), %rax
        addq $24, %rsp
-       jmp *%rdi
+       JMP_NOSPEC %rdi
 #endif