This is a note to let you know that I've just added the patch titled
x86/cpu: Rename original retbleed methods
to the 5.15-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-cpu-rename-original-retbleed-methods.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d025b7bac07a6e90b6b98b487f88854ad9247c39 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Mon, 14 Aug 2023 13:44:32 +0200
Subject: x86/cpu: Rename original retbleed methods
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit d025b7bac07a6e90b6b98b487f88854ad9247c39 upstream.
Rename the original retbleed return thunk and untrain_ret to
retbleed_return_thunk() and retbleed_untrain_ret().
No functional changes.
Suggested-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230814121148.909378169@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/nospec-branch.h | 8 ++++----
arch/x86/kernel/cpu/bugs.c | 2 +-
arch/x86/kernel/vmlinux.lds.S | 2 +-
arch/x86/lib/retpoline.S | 30 +++++++++++++++---------------
tools/objtool/arch/x86/decode.c | 2 +-
tools/objtool/check.c | 2 +-
6 files changed, 23 insertions(+), 23 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -156,7 +156,7 @@
.endm
#ifdef CONFIG_CPU_UNRET_ENTRY
-#define CALL_ZEN_UNTRAIN_RET "call zen_untrain_ret"
+#define CALL_ZEN_UNTRAIN_RET "call retbleed_untrain_ret"
#else
#define CALL_ZEN_UNTRAIN_RET ""
#endif
@@ -166,7 +166,7 @@
* return thunk isn't mapped into the userspace tables (then again, AMD
* typically has NO_MELTDOWN).
*
- * While zen_untrain_ret() doesn't clobber anything but requires stack,
+ * While retbleed_untrain_ret() doesn't clobber anything but requires stack,
* entry_ibpb() will clobber AX, CX, DX.
*
* As such, this must be placed after every *SWITCH_TO_KERNEL_CR3 at a point
@@ -201,11 +201,11 @@ extern void __x86_return_thunk(void);
static inline void __x86_return_thunk(void) {}
#endif
-extern void zen_return_thunk(void);
+extern void retbleed_return_thunk(void);
extern void srso_return_thunk(void);
extern void srso_alias_return_thunk(void);
-extern void zen_untrain_ret(void);
+extern void retbleed_untrain_ret(void);
extern void srso_untrain_ret(void);
extern void srso_untrain_ret_alias(void);
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1021,7 +1021,7 @@ do_cmd_auto:
setup_force_cpu_cap(X86_FEATURE_UNRET);
if (IS_ENABLED(CONFIG_RETHUNK))
- x86_return_thunk = zen_return_thunk;
+ x86_return_thunk = retbleed_return_thunk;
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -512,7 +512,7 @@ INIT_PER_CPU(irq_stack_backing_store);
#endif
#ifdef CONFIG_RETHUNK
-. = ASSERT((zen_return_thunk & 0x3f) == 0, "zen_return_thunk not cacheline-aligned");
+. = ASSERT((retbleed_return_thunk & 0x3f) == 0, "retbleed_return_thunk not cacheline-aligned");
. = ASSERT((srso_safe_ret & 0x3f) == 0, "srso_safe_ret not cacheline-aligned");
#endif
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -129,32 +129,32 @@ SYM_CODE_END(srso_alias_return_thunk)
/*
* Safety details here pertain to the AMD Zen{1,2} microarchitecture:
- * 1) The RET at zen_return_thunk must be on a 64 byte boundary, for
+ * 1) The RET at retbleed_return_thunk must be on a 64 byte boundary, for
* alignment within the BTB.
- * 2) The instruction at zen_untrain_ret must contain, and not
+ * 2) The instruction at retbleed_untrain_ret must contain, and not
* end with, the 0xc3 byte of the RET.
* 3) STIBP must be enabled, or SMT disabled, to prevent the sibling thread
* from re-poisioning the BTB prediction.
*/
.align 64
- .skip 64 - (zen_return_thunk - zen_untrain_ret), 0xcc
-SYM_FUNC_START_NOALIGN(zen_untrain_ret);
+ .skip 64 - (retbleed_return_thunk - retbleed_untrain_ret), 0xcc
+SYM_FUNC_START_NOALIGN(retbleed_untrain_ret);
/*
- * As executed from zen_untrain_ret, this is:
+ * As executed from retbleed_untrain_ret, this is:
*
* TEST $0xcc, %bl
* LFENCE
- * JMP zen_return_thunk
+ * JMP retbleed_return_thunk
*
* Executing the TEST instruction has a side effect of evicting any BTB
* prediction (potentially attacker controlled) attached to the RET, as
- * zen_return_thunk + 1 isn't an instruction boundary at the moment.
+ * retbleed_return_thunk + 1 isn't an instruction boundary at the moment.
*/
.byte 0xf6
/*
- * As executed from zen_return_thunk, this is a plain RET.
+ * As executed from retbleed_return_thunk, this is a plain RET.
*
* As part of the TEST above, RET is the ModRM byte, and INT3 the imm8.
*
@@ -166,13 +166,13 @@ SYM_FUNC_START_NOALIGN(zen_untrain_ret);
* With SMT enabled and STIBP active, a sibling thread cannot poison
* RET's prediction to a type of its choice, but can evict the
* prediction due to competitive sharing. If the prediction is
- * evicted, zen_return_thunk will suffer Straight Line Speculation
+ * evicted, retbleed_return_thunk will suffer Straight Line Speculation
* which will be contained safely by the INT3.
*/
-SYM_INNER_LABEL(zen_return_thunk, SYM_L_GLOBAL)
+SYM_INNER_LABEL(retbleed_return_thunk, SYM_L_GLOBAL)
ret
int3
-SYM_CODE_END(zen_return_thunk)
+SYM_CODE_END(retbleed_return_thunk)
/*
* Ensure the TEST decoding / BTB invalidation is complete.
@@ -183,13 +183,13 @@ SYM_CODE_END(zen_return_thunk)
* Jump back and execute the RET in the middle of the TEST instruction.
* INT3 is for SLS protection.
*/
- jmp zen_return_thunk
+ jmp retbleed_return_thunk
int3
-SYM_FUNC_END(zen_untrain_ret)
-__EXPORT_THUNK(zen_untrain_ret)
+SYM_FUNC_END(retbleed_untrain_ret)
+__EXPORT_THUNK(retbleed_untrain_ret)
/*
- * SRSO untraining sequence for Zen1/2, similar to zen_untrain_ret()
+ * SRSO untraining sequence for Zen1/2, similar to retbleed_untrain_ret()
* above. On kernel entry, srso_untrain_ret() is executed which is a
*
* movabs $0xccccccc308c48348,%rax
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -728,5 +728,5 @@ bool arch_is_rethunk(struct symbol *sym)
return !strcmp(sym->name, "__x86_return_thunk") ||
!strcmp(sym->name, "srso_untrain_ret") ||
!strcmp(sym->name, "srso_safe_ret") ||
- !strcmp(sym->name, "zen_return_thunk");
+ !strcmp(sym->name, "retbleed_return_thunk");
}
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1228,7 +1228,7 @@ static int add_jump_destinations(struct
continue;
/*
- * This is a special case for zen_untrain_ret().
+ * This is a special case for retbleed_untrain_ret().
* It jumps to __x86_return_thunk(), but objtool
* can't find the thunk's starting RET
* instruction, because the RET is also in the
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-5.15/x86-cpu-fix-up-srso_safe_ret-and-__x86_return_thunk.patch
queue-5.15/x86-static_call-fix-__static_call_fixup.patch
queue-5.15/x86-cpu-cleanup-the-untrain-mess.patch
queue-5.15/iopoll-call-cpu_relax-in-busy-loops.patch
queue-5.15/objtool-x86-fixup-frame-pointer-vs-rethunk.patch
queue-5.15/x86-retpoline-kprobes-fix-position-of-thunk-sections-with-config_lto_clang.patch
queue-5.15/x86-cpu-rename-srso_-.-_alias-to-srso_alias_-1.patch
queue-5.15/x86-alternative-make-custom-return-thunk-unconditional.patch
queue-5.15/x86-cpu-rename-original-retbleed-methods.patch
queue-5.15/x86-cpu-clean-up-srso-return-thunk-mess.patch
queue-5.15/x86-cpu-fix-__x86_return_thunk-symbol-type.patch
