From: Peter Zijlstra Date: Mon, 14 Aug 2023 11:44:32 +0000 (+0200) Subject: x86/cpu: Rename original retbleed methods X-Git-Tag: v6.6.17~4191^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d025b7bac07a6e90b6b98b487f88854ad9247c39;p=platform%2Fkernel%2Flinux-rpi.git 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 Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230814121148.909378169@infradead.org --- diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 5ed78ad9..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..7c0e2b4f 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