[tip: x86/urgent] x86/cpu: Rename original retbleed methods

From: tip-bot2 for Peter Zijlstra
Date: Wed Aug 16 2023 - 17:21:02 EST


The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: d025b7bac07a6e90b6b98b487f88854ad9247c39
Gitweb: https://git.kernel.org/tip/d025b7bac07a6e90b6b98b487f88854ad9247c39
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 14 Aug 2023 13:44:32 +02:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Wed, 16 Aug 2023 21:47:53 +02:00

x86/cpu: Rename original retbleed methods

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
---
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(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 5ed78ad..8a0d4c5 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -272,7 +272,7 @@
.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
@@ -282,7 +282,7 @@
* 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
@@ -347,11 +347,11 @@ 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);

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 56cf250..bbbbda9 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1043,7 +1043,7 @@ 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)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index d3b02d6..7c0e2b4 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -521,7 +521,7 @@ 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

diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 7df8582..adabd07 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -188,32 +188,32 @@ 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_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
+ .skip 64 - (retbleed_return_thunk - retbleed_untrain_ret), 0xcc
+SYM_START(retbleed_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
ANNOTATE_NOENDBR
/*
- * 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.
*
@@ -225,13 +225,13 @@ SYM_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
* 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.
@@ -242,13 +242,13 @@ 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 $0xccccc30824648d48,%rax
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index c55f3bb..c0f25d0 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -829,6 +829,6 @@ bool arch_is_rethunk(struct symbol *sym)

bool arch_is_embedded_insn(struct symbol *sym)
{
- return !strcmp(sym->name, "zen_return_thunk") ||
+ return !strcmp(sym->name, "retbleed_return_thunk") ||
!strcmp(sym->name, "srso_safe_ret");
}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 191656e..7a9aaf4 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1593,7 +1593,7 @@ static int add_jump_destinations(struct objtool_file *file)
struct symbol *sym = find_symbol_by_offset(dest_sec, dest_off);

/*
- * 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