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Patch "x86/retpoline/ftrace: Convert ftrace assembler indirect jumps" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message Jan 17, 2018

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This is a note to let you know that I've just added the patch titled

x86/retpoline/ftrace: Convert ftrace assembler indirect jumps

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 9351803bd803cdbeb9b5a7850b7b6f464806e3db Mon Sep 17 00:00:00 2001

From: David Woodhouse <[email protected]>
Date: Thu, 11 Jan 2018 21:46:29 +0000
Subject: x86/retpoline/ftrace: Convert ftrace assembler indirect jumps

From: David Woodhouse <[email protected]>

commit 9351803bd803cdbeb9b5a7850b7b6f464806e3db upstream.

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

---
 arch/x86/entry/entry_32.S   |    5 +++--
 arch/x86/kernel/mcount_64.S |    7 ++++---
 2 files changed, 7 insertions(+), 5 deletions(-)
arch/x86/entry/entry_32.S +3 -2
@@ -862,7 +862,8 @@ 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
@@ -897,7 +898,7 @@ return_to_handler:
 	movl	%eax, %ecx
 	popl	%edx
 	popl	%eax
-	jmp	*%ecx
+	JMP_NOSPEC %ecx
 #endif
 
 #ifdef CONFIG_TRACING
arch/x86/kernel/mcount_64.S +4 -3
@@ -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

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch queue-4.4/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch queue-4.4/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch queue-4.4/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch queue-4.4/x86-cpu-amd-make-lfence-a-serializing-instruction.patch queue-4.4/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch queue-4.4/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch queue-4.4/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch queue-4.4/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch queue-4.4/x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch queue-4.4/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch queue-4.4/x86-retpoline-remove-compile-time-warning.patch queue-4.4/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch queue-4.4/x86-retpoline-add-initial-retpoline-support.patch