Convert all indirect jumps in ftrace assembler code to use non-speculative
sequences when CONFIG_RETPOLINE is enabled.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
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..eb9a56f 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
+ NOSPEC_CALL ecx
popl %edx
popl %ecx
@@ -241,5 +243,5 @@ return_to_handler:
movl %eax, %ecx
popl %edx
popl %eax
- jmp *%ecx
+ NOSPEC_JMP ecx
#endif
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index c832291..d4611d8 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
+ NOSPEC_CALL 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
+ NOSPEC_JMP rdi
#endif
--
2.7.4
