4.4-stable review patch. If anyone has any objections, please let me know.
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From: David Woodhouse dwmw@amazon.co.uk
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.u... 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 --- arch/x86/entry/entry_32.S | 5 +++-- arch/x86/kernel/mcount_64.S | 7 ++++--- 2 files changed, 7 insertions(+), 5 deletions(-)
--- 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 --- 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