605 lines
20 KiB
Diff
605 lines
20 KiB
Diff
diff --git a/Documentation/admin-guide/hw-vuln/srso.rst b/Documentation/admin-guide/hw-vuln/srso.rst
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index 2f923c805802f..f79cb11b080f6 100644
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--- a/Documentation/admin-guide/hw-vuln/srso.rst
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+++ b/Documentation/admin-guide/hw-vuln/srso.rst
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@@ -124,8 +124,8 @@ sequence.
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To ensure the safety of this mitigation, the kernel must ensure that the
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safe return sequence is itself free from attacker interference. In Zen3
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and Zen4, this is accomplished by creating a BTB alias between the
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-untraining function srso_untrain_ret_alias() and the safe return
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-function srso_safe_ret_alias() which results in evicting a potentially
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+untraining function srso_alias_untrain_ret() and the safe return
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+function srso_alias_safe_ret() which results in evicting a potentially
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poisoned BTB entry and using that safe one for all function returns.
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In older Zen1 and Zen2, this is accomplished using a reinterpretation
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diff --git a/Makefile b/Makefile
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index 375efcfb91f8f..8bb8dd199c552 100644
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--- a/Makefile
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+++ b/Makefile
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@@ -1,7 +1,7 @@
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# SPDX-License-Identifier: GPL-2.0
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VERSION = 6
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PATCHLEVEL = 1
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-SUBLEVEL = 47
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+SUBLEVEL = 48
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EXTRAVERSION =
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NAME = Curry Ramen
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diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h
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index 674ed46d3ceda..11203a9fe0a87 100644
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--- a/arch/x86/include/asm/entry-common.h
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+++ b/arch/x86/include/asm/entry-common.h
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@@ -92,6 +92,7 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
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static __always_inline void arch_exit_to_user_mode(void)
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{
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mds_user_clear_cpu_buffers();
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+ amd_clear_divider();
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}
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#define arch_exit_to_user_mode arch_exit_to_user_mode
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diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
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index 31fa631c8587c..2f123d4fb85b5 100644
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--- a/arch/x86/include/asm/nospec-branch.h
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+++ b/arch/x86/include/asm/nospec-branch.h
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@@ -168,9 +168,9 @@
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.endm
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#ifdef CONFIG_CPU_UNRET_ENTRY
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-#define CALL_ZEN_UNTRAIN_RET "call zen_untrain_ret"
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+#define CALL_UNTRAIN_RET "call entry_untrain_ret"
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#else
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-#define CALL_ZEN_UNTRAIN_RET ""
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+#define CALL_UNTRAIN_RET ""
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#endif
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/*
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@@ -178,7 +178,7 @@
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* return thunk isn't mapped into the userspace tables (then again, AMD
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* typically has NO_MELTDOWN).
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*
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- * While zen_untrain_ret() doesn't clobber anything but requires stack,
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+ * While retbleed_untrain_ret() doesn't clobber anything but requires stack,
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* entry_ibpb() will clobber AX, CX, DX.
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*
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* As such, this must be placed after every *SWITCH_TO_KERNEL_CR3 at a point
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@@ -189,14 +189,9 @@
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defined(CONFIG_CPU_SRSO)
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ANNOTATE_UNRET_END
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ALTERNATIVE_2 "", \
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- CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET, \
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+ CALL_UNTRAIN_RET, X86_FEATURE_UNRET, \
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"call entry_ibpb", X86_FEATURE_ENTRY_IBPB
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#endif
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-
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-#ifdef CONFIG_CPU_SRSO
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- ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
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- "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
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-#endif
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.endm
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#else /* __ASSEMBLY__ */
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@@ -210,10 +205,21 @@
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typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE];
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extern retpoline_thunk_t __x86_indirect_thunk_array[];
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+#ifdef CONFIG_RETHUNK
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extern void __x86_return_thunk(void);
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-extern void zen_untrain_ret(void);
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+#else
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+static inline void __x86_return_thunk(void) {}
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+#endif
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+
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+extern void retbleed_return_thunk(void);
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+extern void srso_return_thunk(void);
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+extern void srso_alias_return_thunk(void);
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+
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+extern void retbleed_untrain_ret(void);
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extern void srso_untrain_ret(void);
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-extern void srso_untrain_ret_alias(void);
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+extern void srso_alias_untrain_ret(void);
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+
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+extern void entry_untrain_ret(void);
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extern void entry_ibpb(void);
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#ifdef CONFIG_RETPOLINE
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diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
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index 239b302973d7a..f240c978d85e4 100644
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--- a/arch/x86/kernel/cpu/amd.c
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+++ b/arch/x86/kernel/cpu/amd.c
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@@ -1295,3 +1295,4 @@ void noinstr amd_clear_divider(void)
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asm volatile(ALTERNATIVE("", "div %2\n\t", X86_BUG_DIV0)
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:: "a" (0), "d" (0), "r" (1));
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}
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+EXPORT_SYMBOL_GPL(amd_clear_divider);
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diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
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index d98f33ea57e47..3a893ab398a01 100644
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--- a/arch/x86/kernel/cpu/bugs.c
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+++ b/arch/x86/kernel/cpu/bugs.c
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@@ -62,6 +62,8 @@ EXPORT_SYMBOL_GPL(x86_pred_cmd);
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static DEFINE_MUTEX(spec_ctrl_mutex);
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+void (*x86_return_thunk)(void) __ro_after_init = &__x86_return_thunk;
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+
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/* Update SPEC_CTRL MSR and its cached copy unconditionally */
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static void update_spec_ctrl(u64 val)
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{
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@@ -164,8 +166,13 @@ void __init cpu_select_mitigations(void)
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md_clear_select_mitigation();
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srbds_select_mitigation();
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l1d_flush_select_mitigation();
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- gds_select_mitigation();
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+
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+ /*
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+ * srso_select_mitigation() depends and must run after
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+ * retbleed_select_mitigation().
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+ */
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srso_select_mitigation();
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+ gds_select_mitigation();
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}
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/*
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@@ -1013,6 +1020,9 @@ do_cmd_auto:
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setup_force_cpu_cap(X86_FEATURE_RETHUNK);
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setup_force_cpu_cap(X86_FEATURE_UNRET);
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+ if (IS_ENABLED(CONFIG_RETHUNK))
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+ x86_return_thunk = retbleed_return_thunk;
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+
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if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
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boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
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pr_err(RETBLEED_UNTRAIN_MSG);
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@@ -2388,9 +2398,10 @@ static void __init srso_select_mitigation(void)
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* Zen1/2 with SMT off aren't vulnerable after the right
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* IBPB microcode has been applied.
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*/
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- if ((boot_cpu_data.x86 < 0x19) &&
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- (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED)))
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+ if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) {
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setup_force_cpu_cap(X86_FEATURE_SRSO_NO);
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+ return;
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+ }
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}
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if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB) {
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@@ -2419,11 +2430,15 @@ static void __init srso_select_mitigation(void)
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* like ftrace, static_call, etc.
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*/
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setup_force_cpu_cap(X86_FEATURE_RETHUNK);
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+ setup_force_cpu_cap(X86_FEATURE_UNRET);
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- if (boot_cpu_data.x86 == 0x19)
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+ if (boot_cpu_data.x86 == 0x19) {
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setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS);
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- else
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+ x86_return_thunk = srso_alias_return_thunk;
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+ } else {
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setup_force_cpu_cap(X86_FEATURE_SRSO);
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+ x86_return_thunk = srso_return_thunk;
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+ }
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srso_mitigation = SRSO_MITIGATION_SAFE_RET;
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} else {
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pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
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@@ -2672,6 +2687,9 @@ static ssize_t gds_show_state(char *buf)
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static ssize_t srso_show_state(char *buf)
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{
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+ if (boot_cpu_has(X86_FEATURE_SRSO_NO))
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+ return sysfs_emit(buf, "Mitigation: SMT disabled\n");
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+
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return sysfs_emit(buf, "%s%s\n",
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srso_strings[srso_mitigation],
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(cpu_has_ibpb_brtype_microcode() ? "" : ", no microcode"));
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diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c
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index a9b54b795ebff..3fbb491688275 100644
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--- a/arch/x86/kernel/static_call.c
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+++ b/arch/x86/kernel/static_call.c
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@@ -184,6 +184,19 @@ EXPORT_SYMBOL_GPL(arch_static_call_transform);
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*/
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bool __static_call_fixup(void *tramp, u8 op, void *dest)
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{
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+ unsigned long addr = (unsigned long)tramp;
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+ /*
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+ * Not all .return_sites are a static_call trampoline (most are not).
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+ * Check if the 3 bytes after the return are still kernel text, if not,
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+ * then this definitely is not a trampoline and we need not worry
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+ * further.
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+ *
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+ * This avoids the memcmp() below tripping over pagefaults etc..
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+ */
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+ if (((addr >> PAGE_SHIFT) != ((addr + 7) >> PAGE_SHIFT)) &&
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+ !kernel_text_address(addr + 7))
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+ return false;
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+
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if (memcmp(tramp+5, tramp_ud, 3)) {
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/* Not a trampoline site, not our problem. */
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return false;
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diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
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index 7e8795d8b0f17..c0a5a4f225d9a 100644
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--- a/arch/x86/kernel/traps.c
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+++ b/arch/x86/kernel/traps.c
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@@ -206,8 +206,6 @@ DEFINE_IDTENTRY(exc_divide_error)
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{
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do_error_trap(regs, 0, "divide error", X86_TRAP_DE, SIGFPE,
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FPE_INTDIV, error_get_trap_addr(regs));
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-
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- amd_clear_divider();
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}
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DEFINE_IDTENTRY(exc_overflow)
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diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
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index e6939ebb606ab..78ccb5ec3c0e7 100644
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--- a/arch/x86/kernel/vmlinux.lds.S
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+++ b/arch/x86/kernel/vmlinux.lds.S
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@@ -134,18 +134,18 @@ SECTIONS
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KPROBES_TEXT
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ALIGN_ENTRY_TEXT_BEGIN
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#ifdef CONFIG_CPU_SRSO
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- *(.text.__x86.rethunk_untrain)
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+ *(.text..__x86.rethunk_untrain)
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#endif
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ENTRY_TEXT
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#ifdef CONFIG_CPU_SRSO
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/*
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- * See the comment above srso_untrain_ret_alias()'s
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+ * See the comment above srso_alias_untrain_ret()'s
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* definition.
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*/
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- . = srso_untrain_ret_alias | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20);
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- *(.text.__x86.rethunk_safe)
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+ . = srso_alias_untrain_ret | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20);
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+ *(.text..__x86.rethunk_safe)
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#endif
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ALIGN_ENTRY_TEXT_END
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SOFTIRQENTRY_TEXT
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@@ -154,8 +154,8 @@ SECTIONS
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#ifdef CONFIG_RETPOLINE
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__indirect_thunk_start = .;
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- *(.text.__x86.indirect_thunk)
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- *(.text.__x86.return_thunk)
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+ *(.text..__x86.indirect_thunk)
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+ *(.text..__x86.return_thunk)
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__indirect_thunk_end = .;
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#endif
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} :text =0xcccc
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@@ -507,8 +507,8 @@ INIT_PER_CPU(irq_stack_backing_store);
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"fixed_percpu_data is not at start of per-cpu area");
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#endif
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- #ifdef CONFIG_RETHUNK
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-. = ASSERT((__ret & 0x3f) == 0, "__ret not cacheline-aligned");
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+#ifdef CONFIG_RETHUNK
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+. = ASSERT((retbleed_return_thunk & 0x3f) == 0, "retbleed_return_thunk not cacheline-aligned");
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. = ASSERT((srso_safe_ret & 0x3f) == 0, "srso_safe_ret not cacheline-aligned");
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#endif
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@@ -523,8 +523,8 @@ INIT_PER_CPU(irq_stack_backing_store);
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* Instead do: (A | B) - (A & B) in order to compute the XOR
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* of the two function addresses:
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*/
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-. = ASSERT(((ABSOLUTE(srso_untrain_ret_alias) | srso_safe_ret_alias) -
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- (ABSOLUTE(srso_untrain_ret_alias) & srso_safe_ret_alias)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)),
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+. = ASSERT(((ABSOLUTE(srso_alias_untrain_ret) | srso_alias_safe_ret) -
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+ (ABSOLUTE(srso_alias_untrain_ret) & srso_alias_safe_ret)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)),
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"SRSO function pair won't alias");
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#endif
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diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
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index fdb6007f2eb86..a96f9a17e8b5d 100644
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--- a/arch/x86/kvm/svm/svm.c
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+++ b/arch/x86/kvm/svm/svm.c
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@@ -3947,6 +3947,8 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu, bool spec_ctrl_in
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guest_state_enter_irqoff();
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+ amd_clear_divider();
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+
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if (sev_es_guest(vcpu->kvm))
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__svm_sev_es_vcpu_run(svm, spec_ctrl_intercepted);
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else
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diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
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index 30e76fab678a5..65c5c44f006bc 100644
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--- a/arch/x86/lib/retpoline.S
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+++ b/arch/x86/lib/retpoline.S
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@@ -11,7 +11,7 @@
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#include <asm/frame.h>
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#include <asm/nops.h>
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- .section .text.__x86.indirect_thunk
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+ .section .text..__x86.indirect_thunk
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.macro RETPOLINE reg
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ANNOTATE_INTRA_FUNCTION_CALL
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@@ -76,75 +76,106 @@ SYM_CODE_END(__x86_indirect_thunk_array)
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#ifdef CONFIG_RETHUNK
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/*
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- * srso_untrain_ret_alias() and srso_safe_ret_alias() are placed at
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+ * srso_alias_untrain_ret() and srso_alias_safe_ret() are placed at
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* special addresses:
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*
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- * - srso_untrain_ret_alias() is 2M aligned
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- * - srso_safe_ret_alias() is also in the same 2M page but bits 2, 8, 14
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+ * - srso_alias_untrain_ret() is 2M aligned
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+ * - srso_alias_safe_ret() is also in the same 2M page but bits 2, 8, 14
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* and 20 in its virtual address are set (while those bits in the
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- * srso_untrain_ret_alias() function are cleared).
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+ * srso_alias_untrain_ret() function are cleared).
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*
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* This guarantees that those two addresses will alias in the branch
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* target buffer of Zen3/4 generations, leading to any potential
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* poisoned entries at that BTB slot to get evicted.
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*
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- * As a result, srso_safe_ret_alias() becomes a safe return.
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+ * As a result, srso_alias_safe_ret() becomes a safe return.
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*/
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#ifdef CONFIG_CPU_SRSO
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- .section .text.__x86.rethunk_untrain
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+ .section .text..__x86.rethunk_untrain
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-SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
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+SYM_START(srso_alias_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
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+ UNWIND_HINT_FUNC
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ANNOTATE_NOENDBR
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ASM_NOP2
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lfence
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- jmp __x86_return_thunk
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-SYM_FUNC_END(srso_untrain_ret_alias)
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-__EXPORT_THUNK(srso_untrain_ret_alias)
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+ jmp srso_alias_return_thunk
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+SYM_FUNC_END(srso_alias_untrain_ret)
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+__EXPORT_THUNK(srso_alias_untrain_ret)
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- .section .text.__x86.rethunk_safe
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+ .section .text..__x86.rethunk_safe
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+#else
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+/* dummy definition for alternatives */
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+SYM_START(srso_alias_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
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+ ANNOTATE_UNRET_SAFE
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+ ret
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+ int3
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+SYM_FUNC_END(srso_alias_untrain_ret)
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#endif
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-/* Needs a definition for the __x86_return_thunk alternative below. */
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-SYM_START(srso_safe_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
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-#ifdef CONFIG_CPU_SRSO
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- add $8, %_ASM_SP
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+SYM_START(srso_alias_safe_ret, SYM_L_GLOBAL, SYM_A_NONE)
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+ lea 8(%_ASM_SP), %_ASM_SP
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UNWIND_HINT_FUNC
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-#endif
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ANNOTATE_UNRET_SAFE
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ret
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int3
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-SYM_FUNC_END(srso_safe_ret_alias)
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+SYM_FUNC_END(srso_alias_safe_ret)
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+
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+ .section .text..__x86.return_thunk
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- .section .text.__x86.return_thunk
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+SYM_CODE_START(srso_alias_return_thunk)
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+ UNWIND_HINT_FUNC
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+ ANNOTATE_NOENDBR
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+ call srso_alias_safe_ret
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+ ud2
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+SYM_CODE_END(srso_alias_return_thunk)
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+
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+/*
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+ * Some generic notes on the untraining sequences:
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+ *
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+ * They are interchangeable when it comes to flushing potentially wrong
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+ * RET predictions from the BTB.
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+ *
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+ * The SRSO Zen1/2 (MOVABS) untraining sequence is longer than the
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+ * Retbleed sequence because the return sequence done there
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|
+ * (srso_safe_ret()) is longer and the return sequence must fully nest
|
|
+ * (end before) the untraining sequence. Therefore, the untraining
|
|
+ * sequence must fully overlap the return sequence.
|
|
+ *
|
|
+ * Regarding alignment - the instructions which need to be untrained,
|
|
+ * must all start at a cacheline boundary for Zen1/2 generations. That
|
|
+ * is, instruction sequences starting at srso_safe_ret() and
|
|
+ * the respective instruction sequences at retbleed_return_thunk()
|
|
+ * must start at a cacheline boundary.
|
|
+ */
|
|
|
|
/*
|
|
* Safety details here pertain to the AMD Zen{1,2} microarchitecture:
|
|
- * 1) The RET at __x86_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 - (__ret - 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 __x86_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
|
|
- * __x86_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 __x86_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.
|
|
*
|
|
@@ -156,13 +187,13 @@ 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, __x86_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(__ret, SYM_L_GLOBAL)
|
|
+SYM_INNER_LABEL(retbleed_return_thunk, SYM_L_GLOBAL)
|
|
ret
|
|
int3
|
|
-SYM_CODE_END(__ret)
|
|
+SYM_CODE_END(retbleed_return_thunk)
|
|
|
|
/*
|
|
* Ensure the TEST decoding / BTB invalidation is complete.
|
|
@@ -173,16 +204,16 @@ SYM_CODE_END(__ret)
|
|
* Jump back and execute the RET in the middle of the TEST instruction.
|
|
* INT3 is for SLS protection.
|
|
*/
|
|
- jmp __ret
|
|
+ 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
|
|
+ * movabs $0xccccc30824648d48,%rax
|
|
*
|
|
* and when the return thunk executes the inner label srso_safe_ret()
|
|
* later, it is a stack manipulation and a RET which is mispredicted and
|
|
@@ -194,22 +225,44 @@ SYM_START(srso_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
|
|
ANNOTATE_NOENDBR
|
|
.byte 0x48, 0xb8
|
|
|
|
+/*
|
|
+ * This forces the function return instruction to speculate into a trap
|
|
+ * (UD2 in srso_return_thunk() below). This RET will then mispredict
|
|
+ * and execution will continue at the return site read from the top of
|
|
+ * the stack.
|
|
+ */
|
|
SYM_INNER_LABEL(srso_safe_ret, SYM_L_GLOBAL)
|
|
- add $8, %_ASM_SP
|
|
+ lea 8(%_ASM_SP), %_ASM_SP
|
|
ret
|
|
int3
|
|
int3
|
|
- int3
|
|
+ /* end of movabs */
|
|
lfence
|
|
call srso_safe_ret
|
|
- int3
|
|
+ ud2
|
|
SYM_CODE_END(srso_safe_ret)
|
|
SYM_FUNC_END(srso_untrain_ret)
|
|
__EXPORT_THUNK(srso_untrain_ret)
|
|
|
|
-SYM_FUNC_START(__x86_return_thunk)
|
|
- ALTERNATIVE_2 "jmp __ret", "call srso_safe_ret", X86_FEATURE_SRSO, \
|
|
- "call srso_safe_ret_alias", X86_FEATURE_SRSO_ALIAS
|
|
+SYM_CODE_START(srso_return_thunk)
|
|
+ UNWIND_HINT_FUNC
|
|
+ ANNOTATE_NOENDBR
|
|
+ call srso_safe_ret
|
|
+ ud2
|
|
+SYM_CODE_END(srso_return_thunk)
|
|
+
|
|
+SYM_FUNC_START(entry_untrain_ret)
|
|
+ ALTERNATIVE_2 "jmp retbleed_untrain_ret", \
|
|
+ "jmp srso_untrain_ret", X86_FEATURE_SRSO, \
|
|
+ "jmp srso_alias_untrain_ret", X86_FEATURE_SRSO_ALIAS
|
|
+SYM_FUNC_END(entry_untrain_ret)
|
|
+__EXPORT_THUNK(entry_untrain_ret)
|
|
+
|
|
+SYM_CODE_START(__x86_return_thunk)
|
|
+ UNWIND_HINT_FUNC
|
|
+ ANNOTATE_NOENDBR
|
|
+ ANNOTATE_UNRET_SAFE
|
|
+ ret
|
|
int3
|
|
SYM_CODE_END(__x86_return_thunk)
|
|
EXPORT_SYMBOL(__x86_return_thunk)
|
|
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
|
|
index a60c5efe34b36..29c35279c7ed8 100644
|
|
--- a/tools/objtool/arch/x86/decode.c
|
|
+++ b/tools/objtool/arch/x86/decode.c
|
|
@@ -799,5 +799,5 @@ 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, "__ret");
|
|
+ !strcmp(sym->name, "retbleed_return_thunk");
|
|
}
|
|
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
|
|
index c2c350933a237..913bd361c3684 100644
|
|
--- a/tools/objtool/check.c
|
|
+++ b/tools/objtool/check.c
|
|
@@ -379,7 +379,7 @@ static int decode_instructions(struct objtool_file *file)
|
|
|
|
if (!strcmp(sec->name, ".noinstr.text") ||
|
|
!strcmp(sec->name, ".entry.text") ||
|
|
- !strncmp(sec->name, ".text.__x86.", 12))
|
|
+ !strncmp(sec->name, ".text..__x86.", 13))
|
|
sec->noinstr = true;
|
|
|
|
for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
|
|
@@ -1430,7 +1430,7 @@ 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
|
|
@@ -2450,12 +2450,17 @@ static int decode_sections(struct objtool_file *file)
|
|
return 0;
|
|
}
|
|
|
|
-static bool is_fentry_call(struct instruction *insn)
|
|
+static bool is_special_call(struct instruction *insn)
|
|
{
|
|
- if (insn->type == INSN_CALL &&
|
|
- insn->call_dest &&
|
|
- insn->call_dest->fentry)
|
|
- return true;
|
|
+ if (insn->type == INSN_CALL) {
|
|
+ struct symbol *dest = insn->call_dest;
|
|
+
|
|
+ if (!dest)
|
|
+ return false;
|
|
+
|
|
+ if (dest->fentry)
|
|
+ return true;
|
|
+ }
|
|
|
|
return false;
|
|
}
|
|
@@ -3448,7 +3453,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
|
|
if (ret)
|
|
return ret;
|
|
|
|
- if (opts.stackval && func && !is_fentry_call(insn) &&
|
|
+ if (opts.stackval && func && !is_special_call(insn) &&
|
|
!has_valid_stack_frame(&state)) {
|
|
WARN_FUNC("call without frame pointer save/setup",
|
|
sec, insn->offset);
|