Re: [PATCH -v3 3/6] x86, NMI, Rewrite NMI handler

Don Zickus
2010-11-02T19:12:08Z

On Wed, Nov 03, 2010 at 02:16:03AM +0800, Huang Ying wrote:
> Hi, Don,
> > @@ -38,7 +38,7 @@ static int profile_timer_exceptions_notify(struct notifier_block *self,
> > static struct notifier_block profile_timer_exceptions_nb = {
> > .notifier_call = profile_timer_exceptions_notify,
> > .next = NULL,
> > - .priority = 0
> > + .priority = NMI_EXT_LOW_PRIOR,
>
> Do not find definition of NMI_EXT_LOW_PRIOR, forget to add it?

Gah. I meant to use NMI_LOW_PRIOR there. Thanks for finding that. Guess
I should any randomness to my compiles.

>
> BTW: Attach a patch I used to test external NMI. Hope that is useful to
> you.

It looks useful. I'll try to play with later this week.

Thanks!

Cheers,
Don

>
> Best Regards,
> Huang Ying
>

> From 99a4accf4ccc36ac79c8663bd08e81884aedddaf Mon Sep 17 00:00:00 2001
> From: Huang Ying <ying.huang@intel.com>
> Date: Thu, 9 Sep 2010 14:28:44 +0800
> Subject: [PATCH 08/38] 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 <ying.huang@intel.com>
> ---
> 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(-)
> create mode 100644 arch/x86/kernel/nmi_inject.c
>
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index 7508508..d6bb833 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -299,4 +299,14 @@ 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
> diff --git a/arch/x86/include/asm/mach_traps.h b/arch/x86/include/asm/mach_traps.h
> index 72a8b52..4235bb3 100644
> --- 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 */
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 2dde3c7..5f98f33 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -119,6 +119,7 @@ obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
> obj-$(CONFIG_SWIOTLB) += pci-swiotlb.o
>
> obj-y += hwerr.o
> +obj-$(CONFIG_NMI_INJECT) += nmi_inject.o
>
> ###
> # 64 bit specific files
> diff --git a/arch/x86/kernel/nmi_inject.c b/arch/x86/kernel/nmi_inject.c
> new file mode 100644
> index 0000000..2b61148
> --- /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 <ying.huang@intel.com>
> + *
> + * 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 <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/debugfs.h>
> +#include <linux/cpu.h>
> +#include <asm/mach_traps.h>
> +#include <asm/apic.h>
> +
> +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");
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index 42f16f7..acfb1a9 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -316,6 +316,34 @@ static int __init setup_unknown_nmi_panic(char *str)
> }
> __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, struct pt_regs *regs)
>
> /* 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, struct pt_regs *regs)
>
> /* 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, struct pt_regs *regs)
> }
>
> reason &= ~NMI_REASON_CLEAR_IOCHK;
> - outb(reason, NMI_REASON_PORT);
> + outb_nmi_reason(reason);
> }
>
> static notrace __kprobes void
> --
> 1.7.1
>