Subject: [RFC] x86, NMI, NMI injecting support This patch implements trigger NMI on specified CPUs. At the same time, the NMI reason (contents of port 0x61) can be faked too. This can be used to debug and test the NMI handler. Signed-off-by: Huang Ying --- arch/x86/Kconfig.debug | 10 +++ arch/x86/include/asm/mach_traps.h | 9 ++ arch/x86/kernel/Makefile | 1 arch/x86/kernel/nmi_inject.c | 117 ++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/traps.c | 34 ++++++++++- 5 files changed, 167 insertions(+), 4 deletions(-) --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -304,4 +304,14 @@ config DEBUG_STRICT_USER_COPY_CHECKS If unsure, or if you run an older (pre 4.4) gcc, say N. +config NMI_INJECT + tristate "NMI injecting support" + depends on DEBUG_KERNEL + ---help--- + This can be used to trigger NMI on specified CPUs. And the + reason of NMI (contents of port 0x61) can be faked + too. This can be used to debug and test the NMI handler. + + If unsure, say N. + endmenu --- a/arch/x86/include/asm/mach_traps.h +++ b/arch/x86/include/asm/mach_traps.h @@ -17,7 +17,7 @@ #define NMI_REASON_CLEAR_IOCHK 0x08 #define NMI_REASON_CLEAR_MASK 0x0f -static inline unsigned char get_nmi_reason(void) +static inline unsigned char __get_nmi_reason(void) { return inb(NMI_REASON_PORT); } @@ -40,4 +40,11 @@ static inline void reassert_nmi(void) unlock_cmos(); } +struct nmi_reason_inject_data { + unsigned char reason; + unsigned char valid : 1; +}; + +extern struct nmi_reason_inject_data nmi_reason_inject_data; + #endif /* _ASM_X86_MACH_DEFAULT_MACH_TRAPS_H */ --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -113,6 +113,7 @@ obj-$(CONFIG_SWIOTLB) += pci-swiotlb.o obj-$(CONFIG_OF) += devicetree.o obj-y += hwerr.o +obj-$(CONFIG_NMI_INJECT) += nmi_inject.o ### # 64 bit specific files --- /dev/null +++ b/arch/x86/kernel/nmi_inject.c @@ -0,0 +1,117 @@ +/* + * NMI injector, for NMI handler testing + * + * Copyright 2010 Intel Corp. + * Author: Huang Ying + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include + +static int nmi_reason_inject_get(void *data, u64 *val) +{ + if (nmi_reason_inject_data.valid) + *val = nmi_reason_inject_data.reason; + else + *val = ~0ULL; + return 0; +} + +static int nmi_reason_inject_set(void *data, u64 val) +{ + nmi_reason_inject_data.reason = val; + nmi_reason_inject_data.valid = 1; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(nmi_reason_inject_fops, nmi_reason_inject_get, + nmi_reason_inject_set, "0x%llx\n"); + +static int nmi_reason_uninject_set(void *data, u64 val) +{ + nmi_reason_inject_data.valid = 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(nmi_reason_uninject_fops, NULL, + nmi_reason_uninject_set, "%llu\n"); + +static int nmi_inject_set(void *data, u64 val) +{ + int cpu; + cpumask_var_t cpu_mask; + + alloc_cpumask_var(&cpu_mask, GFP_KERNEL); + cpumask_clear(cpu_mask); + for_each_online_cpu(cpu) { + if (cpu >= sizeof(val)) + continue; + if (val & (1ULL << cpu)) + cpumask_set_cpu(cpu, cpu_mask); + } + if (!cpumask_empty(cpu_mask)) + apic->send_IPI_mask(cpu_mask, NMI_VECTOR); + free_cpumask_var(cpu_mask); + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(nmi_inject_fops, NULL, nmi_inject_set, "0x%llx\n"); + +static struct dentry *nmi_debug_dir; + +static int __init nmi_inject_init(void) +{ + int rc; + struct dentry *de; + + rc = -ENOMEM; + nmi_debug_dir = debugfs_create_dir("nmi", NULL); + if (!nmi_debug_dir) + return rc; + de = debugfs_create_file("inject", S_IWUSR, nmi_debug_dir, + NULL, &nmi_inject_fops); + if (!de) + goto err; + de = debugfs_create_file("reason_inject", S_IRUSR | S_IWUSR, + nmi_debug_dir, NULL, &nmi_reason_inject_fops); + if (!de) + goto err; + de = debugfs_create_file("reason_uninject", S_IWUSR, + nmi_debug_dir, NULL, &nmi_reason_uninject_fops); + if (!de) + goto err; + + return 0; +err: + debugfs_remove_recursive(nmi_debug_dir); + return rc; +} + +static void __exit nmi_inject_exit(void) +{ + debugfs_remove_recursive(nmi_debug_dir); +} + +module_init(nmi_inject_init); +module_exit(nmi_inject_exit); + +MODULE_AUTHOR("Huang Ying"); +MODULE_DESCRIPTION("NMI injecting support"); +MODULE_LICENSE("GPL"); --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -316,6 +316,34 @@ static int __init setup_unknown_nmi_pani } __setup("unknown_nmi_panic", setup_unknown_nmi_panic); +struct nmi_reason_inject_data nmi_reason_inject_data; +EXPORT_SYMBOL_GPL(nmi_reason_inject_data); + +static inline unsigned char get_nmi_reason(void) +{ + if (nmi_reason_inject_data.valid) + return nmi_reason_inject_data.reason; + else + return __get_nmi_reason(); +} + +static inline void outb_nmi_reason(unsigned char reason) +{ + static unsigned char prev_reason; + + if (nmi_reason_inject_data.valid) { + if (reason & NMI_REASON_CLEAR_SERR) + nmi_reason_inject_data.reason &= ~NMI_REASON_SERR; + if (prev_reason == (reason | NMI_REASON_CLEAR_IOCHK) && + !(reason & NMI_REASON_CLEAR_IOCHK)) + nmi_reason_inject_data.reason &= ~NMI_REASON_IOCHK; + if (!nmi_reason_inject_data.reason) + nmi_reason_inject_data.valid = 0; + prev_reason = reason; + } else + outb(reason, NMI_REASON_PORT); +} + static notrace __kprobes void pci_serr_error(unsigned char reason, struct pt_regs *regs) { @@ -340,7 +368,7 @@ pci_serr_error(unsigned char reason, str /* Clear and disable the PCI SERR error line. */ reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_SERR; - outb(reason, NMI_REASON_PORT); + outb_nmi_reason(reason); } static notrace __kprobes void @@ -358,7 +386,7 @@ io_check_error(unsigned char reason, str /* Re-enable the IOCK line, wait for a few seconds */ reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_IOCHK; - outb(reason, NMI_REASON_PORT); + outb_nmi_reason(reason); i = 20000; while (--i) { @@ -367,7 +395,7 @@ io_check_error(unsigned char reason, str } reason &= ~NMI_REASON_CLEAR_IOCHK; - outb(reason, NMI_REASON_PORT); + outb_nmi_reason(reason); } void set_unknown_nmi_as_hwerr(void)