Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752410AbbLLKLt (ORCPT ); Sat, 12 Dec 2015 05:11:49 -0500 Received: from mail.skyhub.de ([78.46.96.112]:57594 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751724AbbLLKLq (ORCPT ); Sat, 12 Dec 2015 05:11:46 -0500 Date: Sat, 12 Dec 2015 11:11:42 +0100 From: Borislav Petkov To: Tony Luck Cc: Ingo Molnar , Andrew Morton , Andy Lutomirski , Dan Williams , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@ml01.01.org, x86@kernel.org Subject: Re: [PATCHV2 1/3] x86, ras: Add new infrastructure for machine check fixup tables Message-ID: <20151212101142.GA3867@pd.tnic> References: <456153d09e85f2f139020a051caed3ca8f8fca73.1449861203.git.tony.luck@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <456153d09e85f2f139020a051caed3ca8f8fca73.1449861203.git.tony.luck@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7092 Lines: 215 On Thu, Dec 10, 2015 at 01:58:04PM -0800, Tony Luck wrote: > Copy the existing page fault fixup mechanisms to create a new table > to be used when fixing machine checks. Note: > 1) At this time we only provide a macro to annotate assembly code > 2) We assume all fixups will in code builtin to the kernel. > 3) Only for x86_64 > 4) New code under CONFIG_MCE_KERNEL_RECOVERY > > Signed-off-by: Tony Luck > --- > arch/x86/Kconfig | 4 ++++ > arch/x86/include/asm/asm.h | 10 ++++++++-- > arch/x86/include/asm/uaccess.h | 8 ++++++++ > arch/x86/mm/extable.c | 19 +++++++++++++++++++ > include/asm-generic/vmlinux.lds.h | 6 ++++++ > include/linux/module.h | 1 + > kernel/extable.c | 20 ++++++++++++++++++++ > 7 files changed, 66 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 96d058a87100..db5c6e1d6e37 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1001,6 +1001,10 @@ config X86_MCE_INJECT > If you don't know what a machine check is and you don't do kernel > QA it is safe to say n. > > +config MCE_KERNEL_RECOVERY > + depends on X86_MCE && X86_64 > + def_bool y Shouldn't that depend on NVDIMM or whatnot? Looks too generic now. > + > config X86_THERMAL_VECTOR > def_bool y > depends on X86_MCE_INTEL > diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h > index 189679aba703..a5d483ac11fa 100644 > --- a/arch/x86/include/asm/asm.h > +++ b/arch/x86/include/asm/asm.h > @@ -44,13 +44,19 @@ > > /* Exception table entry */ > #ifdef __ASSEMBLY__ > -# define _ASM_EXTABLE(from,to) \ > - .pushsection "__ex_table","a" ; \ > +# define __ASM_EXTABLE(from, to, table) \ > + .pushsection table, "a" ; \ > .balign 8 ; \ > .long (from) - . ; \ > .long (to) - . ; \ > .popsection > > +# define _ASM_EXTABLE(from, to) \ > + __ASM_EXTABLE(from, to, "__ex_table") > + > +# define _ASM_MCEXTABLE(from, to) \ > + __ASM_EXTABLE(from, to, "__mcex_table") > + > # define _ASM_EXTABLE_EX(from,to) \ > .pushsection "__ex_table","a" ; \ > .balign 8 ; \ > diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h > index a8df874f3e88..7b02ca1991b4 100644 > --- a/arch/x86/include/asm/uaccess.h > +++ b/arch/x86/include/asm/uaccess.h > @@ -111,6 +111,14 @@ struct exception_table_entry { > #define ARCH_HAS_SEARCH_EXTABLE > > extern int fixup_exception(struct pt_regs *regs); > +#ifdef CONFIG_MCE_KERNEL_RECOVERY > +extern int fixup_mcexception(struct pt_regs *regs, u64 addr); > +#else > +static inline int fixup_mcexception(struct pt_regs *regs, u64 addr) > +{ > + return 0; > +} > +#endif > extern int early_fixup_exception(unsigned long *ip); No need for "extern" > > /* > diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c > index 903ec1e9c326..a461c4212758 100644 > --- a/arch/x86/mm/extable.c > +++ b/arch/x86/mm/extable.c > @@ -49,6 +49,25 @@ int fixup_exception(struct pt_regs *regs) > return 0; > } > > +#ifdef CONFIG_MCE_KERNEL_RECOVERY > +int fixup_mcexception(struct pt_regs *regs, u64 addr) > +{ If you move the #ifdef here, you can save yourself the ifdeffery in the header above. > + const struct exception_table_entry *fixup; > + unsigned long new_ip; > + > + fixup = search_mcexception_tables(regs->ip); > + if (fixup) { > + new_ip = ex_fixup_addr(fixup); > + > + regs->ip = new_ip; > + regs->ax = BIT(63) | addr; > + return 1; > + } > + > + return 0; > +} > +#endif > + > /* Restricted version used during very early boot */ > int __init early_fixup_exception(unsigned long *ip) > { > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 1781e54ea6d3..21bb20d1172a 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -473,6 +473,12 @@ > VMLINUX_SYMBOL(__start___ex_table) = .; \ > *(__ex_table) \ > VMLINUX_SYMBOL(__stop___ex_table) = .; \ > + } \ > + . = ALIGN(align); \ > + __mcex_table : AT(ADDR(__mcex_table) - LOAD_OFFSET) { \ > + VMLINUX_SYMBOL(__start___mcex_table) = .; \ > + *(__mcex_table) \ > + VMLINUX_SYMBOL(__stop___mcex_table) = .; \ Of all the places, this one is missing #ifdef CONFIG_MCE_KERNEL_RECOVERY. > } > > /* > diff --git a/include/linux/module.h b/include/linux/module.h > index 3a19c79918e0..ffecbfcc462c 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -270,6 +270,7 @@ extern const typeof(name) __mod_##type##__##name##_device_table \ > > /* Given an address, look for it in the exception tables */ > const struct exception_table_entry *search_exception_tables(unsigned long add); > +const struct exception_table_entry *search_mcexception_tables(unsigned long a); > > struct notifier_block; > > diff --git a/kernel/extable.c b/kernel/extable.c > index e820ccee9846..7b224fbcb708 100644 > --- a/kernel/extable.c > +++ b/kernel/extable.c > @@ -34,6 +34,10 @@ DEFINE_MUTEX(text_mutex); > > extern struct exception_table_entry __start___ex_table[]; > extern struct exception_table_entry __stop___ex_table[]; > +#ifdef CONFIG_MCE_KERNEL_RECOVERY > +extern struct exception_table_entry __start___mcex_table[]; > +extern struct exception_table_entry __stop___mcex_table[]; > +#endif > > /* Cleared by build time tools if the table is already sorted. */ > u32 __initdata __visible main_extable_sort_needed = 1; > @@ -45,6 +49,10 @@ void __init sort_main_extable(void) > pr_notice("Sorting __ex_table...\n"); > sort_extable(__start___ex_table, __stop___ex_table); > } > +#ifdef CONFIG_MCE_KERNEL_RECOVERY > + if (__stop___mcex_table > __start___mcex_table) > + sort_extable(__start___mcex_table, __stop___mcex_table); > +#endif > } > > /* Given an address, look for it in the exception tables. */ > @@ -58,6 +66,18 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr) > return e; > } > > +#ifdef CONFIG_MCE_KERNEL_RECOVERY > +/* Given an address, look for it in the machine check exception tables. */ > +const struct exception_table_entry *search_mcexception_tables( > + unsigned long addr) > +{ > + const struct exception_table_entry *e; > + > + e = search_extable(__start___mcex_table, __stop___mcex_table-1, addr); > + return e; > +} > +#endif You can make this one a bit more readable by doing: /* Given an address, look for it in the machine check exception tables. */ const struct exception_table_entry * search_mcexception_tables(unsigned long addr) { #ifdef CONFIG_MCE_KERNEL_RECOVERY return search_extable(__start___mcex_table, __stop___mcex_table - 1, addr); #endif } -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/