The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f43b9876e857c739d407bc56df288b0ebe1a9164 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra peterz@infradead.org Date: Mon, 27 Jun 2022 22:21:17 +0000 Subject: [PATCH] x86/retbleed: Add fine grained Kconfig knobs
Do fine-grained Kconfig for all the various retbleed parts.
NOTE: if your compiler doesn't support return thunks this will silently 'upgrade' your mitigation to IBPB, you might not like this.
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Borislav Petkov bp@suse.de
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e35eecfb74f2..e58798f636d4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -462,32 +462,6 @@ config GOLDFISH def_bool y depends on X86_GOLDFISH
-config RETPOLINE - bool "Avoid speculative indirect branches in kernel" - select OBJTOOL if HAVE_OBJTOOL - default y - help - Compile kernel with the retpoline compiler options to guard against - kernel-to-user data leaks by avoiding speculative indirect - branches. Requires a compiler with -mindirect-branch=thunk-extern - support for full protection. The kernel may run slower. - -config CC_HAS_SLS - def_bool $(cc-option,-mharden-sls=all) - -config CC_HAS_RETURN_THUNK - def_bool $(cc-option,-mfunction-return=thunk-extern) - -config SLS - bool "Mitigate Straight-Line-Speculation" - depends on CC_HAS_SLS && X86_64 - select OBJTOOL if HAVE_OBJTOOL - default n - help - Compile the kernel with straight-line-speculation options to guard - against straight line speculation. The kernel image might be slightly - larger. - config X86_CPU_RESCTRL bool "x86 CPU resource control support" depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD) @@ -2456,6 +2430,91 @@ source "kernel/livepatch/Kconfig"
endmenu
+config CC_HAS_SLS + def_bool $(cc-option,-mharden-sls=all) + +config CC_HAS_RETURN_THUNK + def_bool $(cc-option,-mfunction-return=thunk-extern) + +menuconfig SPECULATION_MITIGATIONS + bool "Mitigations for speculative execution vulnerabilities" + default y + help + Say Y here to enable options which enable mitigations for + speculative execution hardware vulnerabilities. + + If you say N, all mitigations will be disabled. You really + should know what you are doing to say so. + +if SPECULATION_MITIGATIONS + +config PAGE_TABLE_ISOLATION + bool "Remove the kernel mapping in user mode" + default y + depends on (X86_64 || X86_PAE) + help + This feature reduces the number of hardware side channels by + ensuring that the majority of kernel addresses are not mapped + into userspace. + + See Documentation/x86/pti.rst for more details. + +config RETPOLINE + bool "Avoid speculative indirect branches in kernel" + select OBJTOOL if HAVE_OBJTOOL + default y + help + Compile kernel with the retpoline compiler options to guard against + kernel-to-user data leaks by avoiding speculative indirect + branches. Requires a compiler with -mindirect-branch=thunk-extern + support for full protection. The kernel may run slower. + +config RETHUNK + bool "Enable return-thunks" + depends on RETPOLINE && CC_HAS_RETURN_THUNK + select OBJTOOL if HAVE_OBJTOOL + default y + help + Compile the kernel with the return-thunks compiler option to guard + against kernel-to-user data leaks by avoiding return speculation. + Requires a compiler with -mfunction-return=thunk-extern + support for full protection. The kernel may run slower. + +config CPU_UNRET_ENTRY + bool "Enable UNRET on kernel entry" + depends on CPU_SUP_AMD && RETHUNK + default y + help + Compile the kernel with support for the retbleed=unret mitigation. + +config CPU_IBPB_ENTRY + bool "Enable IBPB on kernel entry" + depends on CPU_SUP_AMD + default y + help + Compile the kernel with support for the retbleed=ibpb mitigation. + +config CPU_IBRS_ENTRY + bool "Enable IBRS on kernel entry" + depends on CPU_SUP_INTEL + default y + help + Compile the kernel with support for the spectre_v2=ibrs mitigation. + This mitigates both spectre_v2 and retbleed at great cost to + performance. + +config SLS + bool "Mitigate Straight-Line-Speculation" + depends on CC_HAS_SLS && X86_64 + select OBJTOOL if HAVE_OBJTOOL + default n + help + Compile the kernel with straight-line-speculation options to guard + against straight line speculation. The kernel image might be slightly + larger. + +endif + config ARCH_HAS_ADD_PAGES def_bool y depends on ARCH_ENABLE_MEMORY_HOTPLUG diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 6e16057737e5..1f40dad30d50 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -15,14 +15,18 @@ endif ifdef CONFIG_CC_IS_GCC RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register) RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix) -RETPOLINE_CFLAGS += $(call cc-option,-mfunction-return=thunk-extern) RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register) endif ifdef CONFIG_CC_IS_CLANG RETPOLINE_CFLAGS := -mretpoline-external-thunk RETPOLINE_VDSO_CFLAGS := -mretpoline -RETPOLINE_CFLAGS += $(call cc-option,-mfunction-return=thunk-extern) endif + +ifdef CONFIG_RETHUNK +RETHUNK_CFLAGS := -mfunction-return=thunk-extern +RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS) +endif + export RETPOLINE_CFLAGS export RETPOLINE_VDSO_CFLAGS
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 074d04e434de..f6907627172b 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -297,6 +297,7 @@ For 32-bit we have the following conventions - kernel is built with * Assumes x86_spec_ctrl_{base,current} to have SPEC_CTRL_IBRS set. */ .macro IBRS_ENTER save_reg +#ifdef CONFIG_CPU_IBRS_ENTRY ALTERNATIVE "jmp .Lend_@", "", X86_FEATURE_KERNEL_IBRS movl $MSR_IA32_SPEC_CTRL, %ecx
@@ -317,6 +318,7 @@ For 32-bit we have the following conventions - kernel is built with shr $32, %rdx wrmsr .Lend_@: +#endif .endm
/* @@ -324,6 +326,7 @@ For 32-bit we have the following conventions - kernel is built with * regs. Must be called after the last RET. */ .macro IBRS_EXIT save_reg +#ifdef CONFIG_CPU_IBRS_ENTRY ALTERNATIVE "jmp .Lend_@", "", X86_FEATURE_KERNEL_IBRS movl $MSR_IA32_SPEC_CTRL, %ecx
@@ -338,6 +341,7 @@ For 32-bit we have the following conventions - kernel is built with shr $32, %rdx wrmsr .Lend_@: +#endif .endm
/* diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index db75da511a36..33d2cd04d254 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -54,9 +54,19 @@ # define DISABLE_RETPOLINE 0 #else # define DISABLE_RETPOLINE ((1 << (X86_FEATURE_RETPOLINE & 31)) | \ - (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)) | \ - (1 << (X86_FEATURE_RETHUNK & 31)) | \ - (1 << (X86_FEATURE_UNRET & 31))) + (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31))) +#endif + +#ifdef CONFIG_RETHUNK +# define DISABLE_RETHUNK 0 +#else +# define DISABLE_RETHUNK (1 << (X86_FEATURE_RETHUNK & 31)) +#endif + +#ifdef CONFIG_CPU_UNRET_ENTRY +# define DISABLE_UNRET 0 +#else +# define DISABLE_UNRET (1 << (X86_FEATURE_UNRET & 31)) #endif
#ifdef CONFIG_INTEL_IOMMU_SVM @@ -91,7 +101,7 @@ #define DISABLED_MASK8 (DISABLE_TDX_GUEST) #define DISABLED_MASK9 (DISABLE_SGX) #define DISABLED_MASK10 0 -#define DISABLED_MASK11 (DISABLE_RETPOLINE) +#define DISABLED_MASK11 (DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET) #define DISABLED_MASK12 0 #define DISABLED_MASK13 0 #define DISABLED_MASK14 0 diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index e3ae331cabb1..73ca20049835 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -19,7 +19,7 @@ #define __ALIGN_STR __stringify(__ALIGN) #endif
-#if defined(CONFIG_RETPOLINE) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) #define RET jmp __x86_return_thunk #else /* CONFIG_RETPOLINE */ #ifdef CONFIG_SLS @@ -31,7 +31,7 @@
#else /* __ASSEMBLY__ */
-#if defined(CONFIG_RETPOLINE) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) #define ASM_RET "jmp __x86_return_thunk\n\t" #else /* CONFIG_RETPOLINE */ #ifdef CONFIG_SLS diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index ccde87e6eabb..bb05ed4f46bd 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -127,6 +127,12 @@ .Lskip_rsb_@: .endm
+#ifdef CONFIG_CPU_UNRET_ENTRY +#define CALL_ZEN_UNTRAIN_RET "call zen_untrain_ret" +#else +#define CALL_ZEN_UNTRAIN_RET "" +#endif + /* * Mitigate RETBleed for AMD/Hygon Zen uarch. Requires KERNEL CR3 because the * return thunk isn't mapped into the userspace tables (then again, AMD @@ -139,10 +145,10 @@ * where we have a stack but before any RET instruction. */ .macro UNTRAIN_RET -#ifdef CONFIG_RETPOLINE +#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) ANNOTATE_UNRET_END ALTERNATIVE_2 "", \ - "call zen_untrain_ret", X86_FEATURE_UNRET, \ + CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET, \ "call entry_ibpb", X86_FEATURE_ENTRY_IBPB #endif .endm diff --git a/arch/x86/include/asm/static_call.h b/arch/x86/include/asm/static_call.h index 70cc9ccb8029..343b722ccaf2 100644 --- a/arch/x86/include/asm/static_call.h +++ b/arch/x86/include/asm/static_call.h @@ -46,7 +46,7 @@ #define ARCH_DEFINE_STATIC_CALL_TRAMP(name, func) \ __ARCH_DEFINE_STATIC_CALL_TRAMP(name, ".byte 0xe9; .long " #func " - (. + 4)")
-#ifdef CONFIG_RETPOLINE +#ifdef CONFIG_RETHUNK #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) \ __ARCH_DEFINE_STATIC_CALL_TRAMP(name, "jmp __x86_return_thunk") #else diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index cf447ee18b3c..d6858533e6e5 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -508,6 +508,7 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) } }
+#ifdef CONFIG_RETHUNK /* * Rewrite the compiler generated return thunk tail-calls. * @@ -569,6 +570,10 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) } } } +#else +void __init_or_module noinline apply_returns(s32 *start, s32 *end) { } +#endif /* CONFIG_RETHUNK */ + #else /* !CONFIG_RETPOLINE || !CONFIG_OBJTOOL */
void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { } diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 9cfd11f7ba11..35d5288394cb 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -864,6 +864,7 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
void init_spectral_chicken(struct cpuinfo_x86 *c) { +#ifdef CONFIG_CPU_UNRET_ENTRY u64 value;
/* @@ -880,6 +881,7 @@ void init_spectral_chicken(struct cpuinfo_x86 *c) wrmsrl_safe(MSR_ZEN2_SPECTRAL_CHICKEN, value); } } +#endif }
static void init_amd_zn(struct cpuinfo_x86 *c) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 182f8b2e8a3c..cf08a1b8f3c7 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -842,7 +842,6 @@ static int __init retbleed_parse_cmdline(char *str) early_param("retbleed", retbleed_parse_cmdline);
#define RETBLEED_UNTRAIN_MSG "WARNING: BTB untrained return thunk mitigation is only effective on AMD/Hygon!\n" -#define RETBLEED_COMPILER_MSG "WARNING: kernel not compiled with RETPOLINE or -mfunction-return capable compiler; falling back to IBPB!\n" #define RETBLEED_INTEL_MSG "WARNING: Spectre v2 mitigation leaves CPU vulnerable to RETBleed attacks, data leaks possible!\n"
static void __init retbleed_select_mitigation(void) @@ -857,18 +856,33 @@ static void __init retbleed_select_mitigation(void) return;
case RETBLEED_CMD_UNRET: - retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) { + retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + } else { + pr_err("WARNING: kernel not compiled with CPU_UNRET_ENTRY.\n"); + goto do_cmd_auto; + } break;
case RETBLEED_CMD_IBPB: - retbleed_mitigation = RETBLEED_MITIGATION_IBPB; + if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) { + retbleed_mitigation = RETBLEED_MITIGATION_IBPB; + } else { + pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n"); + goto do_cmd_auto; + } break;
+do_cmd_auto: case RETBLEED_CMD_AUTO: default: if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || - boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) - retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { + if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) + retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + else if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) + retbleed_mitigation = RETBLEED_MITIGATION_IBPB; + }
/* * The Intel mitigation (IBRS or eIBRS) was already selected in @@ -881,14 +895,6 @@ static void __init retbleed_select_mitigation(void)
switch (retbleed_mitigation) { case RETBLEED_MITIGATION_UNRET: - - if (!IS_ENABLED(CONFIG_RETPOLINE) || - !IS_ENABLED(CONFIG_CC_HAS_RETURN_THUNK)) { - pr_err(RETBLEED_COMPILER_MSG); - retbleed_mitigation = RETBLEED_MITIGATION_IBPB; - goto retbleed_force_ibpb; - } - setup_force_cpu_cap(X86_FEATURE_RETHUNK); setup_force_cpu_cap(X86_FEATURE_UNRET);
@@ -900,7 +906,6 @@ static void __init retbleed_select_mitigation(void) break;
case RETBLEED_MITIGATION_IBPB: -retbleed_force_ibpb: setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); mitigate_smt = true; break; @@ -1271,6 +1276,12 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) return SPECTRE_V2_CMD_AUTO; }
+ if (cmd == SPECTRE_V2_CMD_IBRS && !IS_ENABLED(CONFIG_CPU_IBRS_ENTRY)) { + pr_err("%s selected but not compiled in. Switching to AUTO select\n", + mitigation_options[i].option); + return SPECTRE_V2_CMD_AUTO; + } + if (cmd == SPECTRE_V2_CMD_IBRS && boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) { pr_err("%s selected but not Intel CPU. Switching to AUTO select\n", mitigation_options[i].option); @@ -1328,7 +1339,8 @@ static void __init spectre_v2_select_mitigation(void) break; }
- if (boot_cpu_has_bug(X86_BUG_RETBLEED) && + if (IS_ENABLED(CONFIG_CPU_IBRS_ENTRY) && + boot_cpu_has_bug(X86_BUG_RETBLEED) && retbleed_cmd != RETBLEED_CMD_OFF && boot_cpu_has(X86_FEATURE_IBRS) && boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c index fe21fe778185..be7038a0da4d 100644 --- a/arch/x86/kernel/static_call.c +++ b/arch/x86/kernel/static_call.c @@ -126,7 +126,7 @@ void arch_static_call_transform(void *site, void *tramp, void *func, bool tail) } EXPORT_SYMBOL_GPL(arch_static_call_transform);
-#ifdef CONFIG_RETPOLINE +#ifdef CONFIG_RETHUNK /* * This is called by apply_returns() to fix up static call trampolines, * specifically ARCH_DEFINE_STATIC_CALL_NULL_TRAMP which is recorded as diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index b01437015f99..db96bf7d1122 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -439,10 +439,10 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop); * * ENDBR [4 bytes; CONFIG_X86_KERNEL_IBT] * SETcc %al [3 bytes] - * RET | JMP __x86_return_thunk [1,5 bytes; CONFIG_RETPOLINE] + * RET | JMP __x86_return_thunk [1,5 bytes; CONFIG_RETHUNK] * INT3 [1 byte; CONFIG_SLS] */ -#define RET_LENGTH (1 + (4 * IS_ENABLED(CONFIG_RETPOLINE)) + \ +#define RET_LENGTH (1 + (4 * IS_ENABLED(CONFIG_RETHUNK)) + \ IS_ENABLED(CONFIG_SLS)) #define SETCC_LENGTH (ENDBR_INSN_SIZE + 3 + RET_LENGTH) #define SETCC_ALIGN (4 << ((SETCC_LENGTH > 4) & 1) << ((SETCC_LENGTH > 8) & 1)) diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index fdd16163b996..073289a55f84 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -72,6 +72,8 @@ SYM_CODE_END(__x86_indirect_thunk_array) * This function name is magical and is used by -mfunction-return=thunk-extern * for the compiler to generate JMPs to it. */ +#ifdef CONFIG_RETHUNK + .section .text.__x86.return_thunk
/* @@ -136,3 +138,5 @@ SYM_FUNC_END(zen_untrain_ret) __EXPORT_THUNK(zen_untrain_ret)
EXPORT_SYMBOL(__x86_return_thunk) + +#endif /* CONFIG_RETHUNK */ diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index d1425778664b..3fb6a99e78c4 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -236,6 +236,7 @@ objtool_args = \ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ $(if $(CONFIG_UNWINDER_ORC), --orc) \ $(if $(CONFIG_RETPOLINE), --retpoline) \ + $(if $(CONFIG_RETHUNK), --rethunk) \ $(if $(CONFIG_SLS), --sls) \ $(if $(CONFIG_STACK_VALIDATION), --stackval) \ $(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call) \ diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o index bc67748044a6..84019814f33f 100644 --- a/scripts/Makefile.vmlinux_o +++ b/scripts/Makefile.vmlinux_o @@ -44,7 +44,7 @@ objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
objtool_args := \ $(if $(delay-objtool),$(objtool_args)) \ - $(if $(CONFIG_NOINSTR_VALIDATION), --noinstr $(if $(CONFIG_RETPOLINE), --unret)) \ + $(if $(CONFIG_NOINSTR_VALIDATION), --noinstr $(if $(CONFIG_CPU_UNRET_ENTRY), --unret)) \ $(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \ --link
diff --git a/security/Kconfig b/security/Kconfig index f29e4c656983..e6db09a779b7 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -54,17 +54,6 @@ config SECURITY_NETWORK implement socket and networking access controls. If you are unsure how to answer this question, answer N.
-config PAGE_TABLE_ISOLATION - bool "Remove the kernel mapping in user mode" - default y - depends on (X86_64 || X86_PAE) && !UML - help - This feature reduces the number of hardware side channels by - ensuring that the majority of kernel addresses are not mapped - into userspace. - - See Documentation/x86/pti.rst for more details. - config SECURITY_INFINIBAND bool "Infiniband Security Hooks" depends on SECURITY && INFINIBAND diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index c063e1ff96b2..24fbe803a0d3 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -68,6 +68,7 @@ const struct option check_options[] = { OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"), OPT_BOOLEAN('o', "orc", &opts.orc, "generate ORC metadata"), OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"), + OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"), OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"), OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"), OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"), @@ -124,6 +125,7 @@ static bool opts_valid(void) opts.noinstr || opts.orc || opts.retpoline || + opts.rethunk || opts.sls || opts.stackval || opts.static_call || @@ -136,6 +138,11 @@ static bool opts_valid(void) return true; }
+ if (opts.unret && !opts.rethunk) { + ERROR("--unret requires --rethunk"); + return false; + } + if (opts.dump_orc) return true;
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ddfdd138cc2a..7bebdb8867cd 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3732,8 +3732,11 @@ static int validate_retpoline(struct objtool_file *file) continue;
if (insn->type == INSN_RETURN) { - WARN_FUNC("'naked' return found in RETPOLINE build", - insn->sec, insn->offset); + if (opts.rethunk) { + WARN_FUNC("'naked' return found in RETHUNK build", + insn->sec, insn->offset); + } else + continue; } else { WARN_FUNC("indirect %s found in RETPOLINE build", insn->sec, insn->offset, @@ -4264,7 +4267,9 @@ int check(struct objtool_file *file) if (ret < 0) goto out; warnings += ret; + }
+ if (opts.rethunk) { ret = create_return_sites_sections(file); if (ret < 0) goto out; diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index 0c476b0b40a3..42a52f1a0add 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -19,6 +19,7 @@ struct opts { bool noinstr; bool orc; bool retpoline; + bool rethunk; bool unret; bool sls; bool stackval;