diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 79 | ||||
| -rw-r--r-- | arch/x86/kernel/signal_32.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/signal_64.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/smp.c | 24 | ||||
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 54 |
5 files changed, 94 insertions, 71 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index ecfe7b497cad..6455f7f751b3 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -116,6 +116,24 @@ static struct module *its_mod; #endif static void *its_page; static unsigned int its_offset; +struct its_array its_pages; + +static void *__its_alloc(struct its_array *pages) +{ + void *page __free(execmem) = execmem_alloc(EXECMEM_MODULE_TEXT, PAGE_SIZE); + if (!page) + return NULL; + + void *tmp = krealloc(pages->pages, (pages->num+1) * sizeof(void *), + GFP_KERNEL); + if (!tmp) + return NULL; + + pages->pages = tmp; + pages->pages[pages->num++] = page; + + return no_free_ptr(page); +} /* Initialize a thunk with the "jmp *reg; int3" instructions. */ static void *its_init_thunk(void *thunk, int reg) @@ -151,6 +169,21 @@ static void *its_init_thunk(void *thunk, int reg) return thunk + offset; } +static void its_pages_protect(struct its_array *pages) +{ + for (int i = 0; i < pages->num; i++) { + void *page = pages->pages[i]; + execmem_restore_rox(page, PAGE_SIZE); + } +} + +static void its_fini_core(void) +{ + if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) + its_pages_protect(&its_pages); + kfree(its_pages.pages); +} + #ifdef CONFIG_MODULES void its_init_mod(struct module *mod) { @@ -173,10 +206,8 @@ void its_fini_mod(struct module *mod) its_page = NULL; mutex_unlock(&text_mutex); - for (int i = 0; i < mod->its_num_pages; i++) { - void *page = mod->its_page_array[i]; - execmem_restore_rox(page, PAGE_SIZE); - } + if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) + its_pages_protect(&mod->arch.its_pages); } void its_free_mod(struct module *mod) @@ -184,37 +215,33 @@ void its_free_mod(struct module *mod) if (!cpu_feature_enabled(X86_FEATURE_INDIRECT_THUNK_ITS)) return; - for (int i = 0; i < mod->its_num_pages; i++) { - void *page = mod->its_page_array[i]; + for (int i = 0; i < mod->arch.its_pages.num; i++) { + void *page = mod->arch.its_pages.pages[i]; execmem_free(page); } - kfree(mod->its_page_array); + kfree(mod->arch.its_pages.pages); } #endif /* CONFIG_MODULES */ static void *its_alloc(void) { - void *page __free(execmem) = execmem_alloc(EXECMEM_MODULE_TEXT, PAGE_SIZE); + struct its_array *pages = &its_pages; + void *page; +#ifdef CONFIG_MODULE + if (its_mod) + pages = &its_mod->arch.its_pages; +#endif + + page = __its_alloc(pages); if (!page) return NULL; -#ifdef CONFIG_MODULES - if (its_mod) { - void *tmp = krealloc(its_mod->its_page_array, - (its_mod->its_num_pages+1) * sizeof(void *), - GFP_KERNEL); - if (!tmp) - return NULL; - - its_mod->its_page_array = tmp; - its_mod->its_page_array[its_mod->its_num_pages++] = page; + execmem_make_temp_rw(page, PAGE_SIZE); + if (pages == &its_pages) + set_memory_x((unsigned long)page, 1); - execmem_make_temp_rw(page, PAGE_SIZE); - } -#endif /* CONFIG_MODULES */ - - return no_free_ptr(page); + return page; } static void *its_allocate_thunk(int reg) @@ -268,7 +295,9 @@ u8 *its_static_thunk(int reg) return thunk; } -#endif +#else +static inline void its_fini_core(void) {} +#endif /* CONFIG_MITIGATION_ITS */ /* * Nomenclature for variable names to simplify and clarify this code and ease @@ -2338,6 +2367,8 @@ void __init alternative_instructions(void) apply_retpolines(__retpoline_sites, __retpoline_sites_end); apply_returns(__return_sites, __return_sites_end); + its_fini_core(); + /* * Adjust all CALL instructions to point to func()-10, including * those in .altinstr_replacement. diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c index 98123ff10506..42bbc42bd350 100644 --- a/arch/x86/kernel/signal_32.c +++ b/arch/x86/kernel/signal_32.c @@ -152,6 +152,8 @@ SYSCALL32_DEFINE0(sigreturn) struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8); sigset_t set; + prevent_single_step_upon_eretu(regs); + if (!access_ok(frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.oldmask) @@ -175,6 +177,8 @@ SYSCALL32_DEFINE0(rt_sigreturn) struct rt_sigframe_ia32 __user *frame; sigset_t set; + prevent_single_step_upon_eretu(regs); + frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4); if (!access_ok(frame, sizeof(*frame))) diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index ee9453891901..d483b585c6c6 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -250,6 +250,8 @@ SYSCALL_DEFINE0(rt_sigreturn) sigset_t set; unsigned long uc_flags; + prevent_single_step_upon_eretu(regs); + frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); if (!access_ok(frame, sizeof(*frame))) goto badframe; @@ -366,6 +368,8 @@ COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) sigset_t set; unsigned long uc_flags; + prevent_single_step_upon_eretu(regs); + frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); if (!access_ok(frame, sizeof(*frame))) diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index 18266cc3d98c..b014e6d229f9 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -299,3 +299,27 @@ struct smp_ops smp_ops = { .send_call_func_single_ipi = native_send_call_func_single_ipi, }; EXPORT_SYMBOL_GPL(smp_ops); + +int arch_cpu_rescan_dead_smt_siblings(void) +{ + enum cpuhp_smt_control old = cpu_smt_control; + int ret; + + /* + * If SMT has been disabled and SMT siblings are in HLT, bring them back + * online and offline them again so that they end up in MWAIT proper. + * + * Called with hotplug enabled. + */ + if (old != CPU_SMT_DISABLED && old != CPU_SMT_FORCE_DISABLED) + return 0; + + ret = cpuhp_smt_enable(); + if (ret) + return ret; + + ret = cpuhp_smt_disable(old); + + return ret; +} +EXPORT_SYMBOL_GPL(arch_cpu_rescan_dead_smt_siblings); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index fc78c2325fd2..58ede3fa6a75 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1244,6 +1244,10 @@ void play_dead_common(void) local_irq_disable(); } +/* + * We need to flush the caches before going to sleep, lest we have + * dirty data in our caches when we come back up. + */ void __noreturn mwait_play_dead(unsigned int eax_hint) { struct mwait_cpu_dead *md = this_cpu_ptr(&mwait_cpu_dead); @@ -1290,50 +1294,6 @@ void __noreturn mwait_play_dead(unsigned int eax_hint) } /* - * We need to flush the caches before going to sleep, lest we have - * dirty data in our caches when we come back up. - */ -static inline void mwait_play_dead_cpuid_hint(void) -{ - unsigned int eax, ebx, ecx, edx; - unsigned int highest_cstate = 0; - unsigned int highest_subcstate = 0; - int i; - - if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || - boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) - return; - if (!this_cpu_has(X86_FEATURE_MWAIT)) - return; - if (!this_cpu_has(X86_FEATURE_CLFLUSH)) - return; - - eax = CPUID_LEAF_MWAIT; - ecx = 0; - native_cpuid(&eax, &ebx, &ecx, &edx); - - /* - * eax will be 0 if EDX enumeration is not valid. - * Initialized below to cstate, sub_cstate value when EDX is valid. - */ - if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) { - eax = 0; - } else { - edx >>= MWAIT_SUBSTATE_SIZE; - for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) { - if (edx & MWAIT_SUBSTATE_MASK) { - highest_cstate = i; - highest_subcstate = edx & MWAIT_SUBSTATE_MASK; - } - } - eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) | - (highest_subcstate - 1); - } - - mwait_play_dead(eax); -} - -/* * Kick all "offline" CPUs out of mwait on kexec(). See comment in * mwait_play_dead(). */ @@ -1383,9 +1343,9 @@ void native_play_dead(void) play_dead_common(); tboot_shutdown(TB_SHUTDOWN_WFS); - mwait_play_dead_cpuid_hint(); - if (cpuidle_play_dead()) - hlt_play_dead(); + /* Below returns only on error. */ + cpuidle_play_dead(); + hlt_play_dead(); } #else /* ... !CONFIG_HOTPLUG_CPU */ |