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-rw-r--r--arch/x86/kernel/dumpstack.c2
-rw-r--r--arch/x86/kernel/nmi.c87
-rw-r--r--arch/x86/kernel/nmi_selftest.c52
-rw-r--r--arch/x86/kernel/setup.c35
4 files changed, 74 insertions, 102 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index c6fefd4585f8..71ee20102a8a 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -23,8 +23,6 @@
#include <asm/stacktrace.h>
#include <asm/unwind.h>
-int panic_on_unrecovered_nmi;
-int panic_on_io_nmi;
static int die_counter;
static struct pt_regs exec_summary_regs;
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 9a95d00f1423..be93ec7255bf 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -49,27 +49,20 @@ struct nmi_desc {
struct list_head head;
};
-static struct nmi_desc nmi_desc[NMI_MAX] =
-{
- {
- .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock),
- .head = LIST_HEAD_INIT(nmi_desc[0].head),
- },
- {
- .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),
- .head = LIST_HEAD_INIT(nmi_desc[1].head),
- },
- {
- .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock),
- .head = LIST_HEAD_INIT(nmi_desc[2].head),
- },
- {
- .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock),
- .head = LIST_HEAD_INIT(nmi_desc[3].head),
- },
+#define NMI_DESC_INIT(type) { \
+ .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[type].lock), \
+ .head = LIST_HEAD_INIT(nmi_desc[type].head), \
+}
+static struct nmi_desc nmi_desc[NMI_MAX] = {
+ NMI_DESC_INIT(NMI_LOCAL),
+ NMI_DESC_INIT(NMI_UNKNOWN),
+ NMI_DESC_INIT(NMI_SERR),
+ NMI_DESC_INIT(NMI_IO_CHECK),
};
+#define nmi_to_desc(type) (&nmi_desc[type])
+
struct nmi_stats {
unsigned int normal;
unsigned int unknown;
@@ -91,6 +84,9 @@ static DEFINE_PER_CPU(struct nmi_stats, nmi_stats);
static int ignore_nmis __read_mostly;
int unknown_nmi_panic;
+int panic_on_unrecovered_nmi;
+int panic_on_io_nmi;
+
/*
* Prevent NMI reason port (0x61) being accessed simultaneously, can
* only be used in NMI handler.
@@ -104,8 +100,6 @@ static int __init setup_unknown_nmi_panic(char *str)
}
__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
-#define nmi_to_desc(type) (&nmi_desc[type])
-
static u64 nmi_longest_ns = 1 * NSEC_PER_MSEC;
static int __init nmi_warning_debugfs(void)
@@ -125,12 +119,12 @@ static void nmi_check_duration(struct nmiaction *action, u64 duration)
action->max_duration = duration;
- remainder_ns = do_div(duration, (1000 * 1000));
- decimal_msecs = remainder_ns / 1000;
+ /* Convert duration from nsec to msec */
+ remainder_ns = do_div(duration, NSEC_PER_MSEC);
+ decimal_msecs = remainder_ns / NSEC_PER_USEC;
- printk_ratelimited(KERN_INFO
- "INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
- action->handler, duration, decimal_msecs);
+ pr_info_ratelimited("INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
+ action->handler, duration, decimal_msecs);
}
static int nmi_handle(unsigned int type, struct pt_regs *regs)
@@ -333,10 +327,9 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
int handled;
/*
- * Use 'false' as back-to-back NMIs are dealt with one level up.
- * Of course this makes having multiple 'unknown' handlers useless
- * as only the first one is ever run (unless it can actually determine
- * if it caused the NMI)
+ * As a last resort, let the "unknown" handlers make a
+ * best-effort attempt to figure out if they can claim
+ * responsibility for this Unknown NMI.
*/
handled = nmi_handle(NMI_UNKNOWN, regs);
if (handled) {
@@ -366,17 +359,18 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
bool b2b = false;
/*
- * CPU-specific NMI must be processed before non-CPU-specific
- * NMI, otherwise we may lose it, because the CPU-specific
- * NMI can not be detected/processed on other CPUs.
- */
-
- /*
- * Back-to-back NMIs are interesting because they can either
- * be two NMI or more than two NMIs (any thing over two is dropped
- * due to NMI being edge-triggered). If this is the second half
- * of the back-to-back NMI, assume we dropped things and process
- * more handlers. Otherwise reset the 'swallow' NMI behaviour
+ * Back-to-back NMIs are detected by comparing the RIP of the
+ * current NMI with that of the previous NMI. If it is the same,
+ * it is assumed that the CPU did not have a chance to jump back
+ * into a non-NMI context and execute code in between the two
+ * NMIs.
+ *
+ * They are interesting because even if there are more than two,
+ * only a maximum of two can be detected (anything over two is
+ * dropped due to NMI being edge-triggered). If this is the
+ * second half of the back-to-back NMI, assume we dropped things
+ * and process more handlers. Otherwise, reset the 'swallow' NMI
+ * behavior.
*/
if (regs->ip == __this_cpu_read(last_nmi_rip))
b2b = true;
@@ -390,6 +384,11 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
if (microcode_nmi_handler_enabled() && microcode_nmi_handler())
goto out;
+ /*
+ * CPU-specific NMI must be processed before non-CPU-specific
+ * NMI, otherwise we may lose it, because the CPU-specific
+ * NMI can not be detected/processed on other CPUs.
+ */
handled = nmi_handle(NMI_LOCAL, regs);
__this_cpu_add(nmi_stats.normal, handled);
if (handled) {
@@ -426,13 +425,14 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
pci_serr_error(reason, regs);
else if (reason & NMI_REASON_IOCHK)
io_check_error(reason, regs);
-#ifdef CONFIG_X86_32
+
/*
* Reassert NMI in case it became active
* meanwhile as it's edge-triggered:
*/
- reassert_nmi();
-#endif
+ if (IS_ENABLED(CONFIG_X86_32))
+ reassert_nmi();
+
__this_cpu_add(nmi_stats.external, 1);
raw_spin_unlock(&nmi_reason_lock);
goto out;
@@ -751,4 +751,3 @@ void local_touch_nmi(void)
{
__this_cpu_write(last_nmi_rip, 0);
}
-EXPORT_SYMBOL_GPL(local_touch_nmi);
diff --git a/arch/x86/kernel/nmi_selftest.c b/arch/x86/kernel/nmi_selftest.c
index e93a8545c74d..a010e9d062bf 100644
--- a/arch/x86/kernel/nmi_selftest.c
+++ b/arch/x86/kernel/nmi_selftest.c
@@ -1,7 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * arch/x86/kernel/nmi-selftest.c
- *
* Testsuite for NMI: IPIs
*
* Started by Don Zickus:
@@ -30,7 +28,6 @@ static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __initdata;
static int __initdata testcase_total;
static int __initdata testcase_successes;
-static int __initdata expected_testcase_failures;
static int __initdata unexpected_testcase_failures;
static int __initdata unexpected_testcase_unknowns;
@@ -120,26 +117,22 @@ static void __init dotest(void (*testcase_fn)(void), int expected)
unexpected_testcase_failures++;
if (nmi_fail == FAILURE)
- printk(KERN_CONT "FAILED |");
+ pr_cont("FAILED |");
else if (nmi_fail == TIMEOUT)
- printk(KERN_CONT "TIMEOUT|");
+ pr_cont("TIMEOUT|");
else
- printk(KERN_CONT "ERROR |");
+ pr_cont("ERROR |");
dump_stack();
} else {
testcase_successes++;
- printk(KERN_CONT " ok |");
+ pr_cont(" ok |");
}
- testcase_total++;
+ pr_cont("\n");
+ testcase_total++;
reset_nmi();
}
-static inline void __init print_testname(const char *testname)
-{
- printk("%12s:", testname);
-}
-
void __init nmi_selftest(void)
{
init_nmi_testsuite();
@@ -147,38 +140,25 @@ void __init nmi_selftest(void)
/*
* Run the testsuite:
*/
- printk("----------------\n");
- printk("| NMI testsuite:\n");
- printk("--------------------\n");
+ pr_info("----------------\n");
+ pr_info("| NMI testsuite:\n");
+ pr_info("--------------------\n");
- print_testname("remote IPI");
+ pr_info("%12s:", "remote IPI");
dotest(remote_ipi, SUCCESS);
- printk(KERN_CONT "\n");
- print_testname("local IPI");
+
+ pr_info("%12s:", "local IPI");
dotest(local_ipi, SUCCESS);
- printk(KERN_CONT "\n");
cleanup_nmi_testsuite();
+ pr_info("--------------------\n");
if (unexpected_testcase_failures) {
- printk("--------------------\n");
- printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
+ pr_info("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n",
unexpected_testcase_failures, testcase_total);
- printk("-----------------------------------------------------------------\n");
- } else if (expected_testcase_failures && testcase_successes) {
- printk("--------------------\n");
- printk("%3d out of %3d testcases failed, as expected. |\n",
- expected_testcase_failures, testcase_total);
- printk("----------------------------------------------------\n");
- } else if (expected_testcase_failures && !testcase_successes) {
- printk("--------------------\n");
- printk("All %3d testcases failed, as expected. |\n",
- expected_testcase_failures);
- printk("----------------------------------------\n");
} else {
- printk("--------------------\n");
- printk("Good, all %3d testcases passed! |\n",
+ pr_info("Good, all %3d testcases passed! |\n",
testcase_successes);
- printk("---------------------------------\n");
}
+ pr_info("-----------------------------------------------------------------\n");
}
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index e0cf1595a0ab..7d9ed79a93c0 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -11,6 +11,7 @@
#include <linux/crash_dump.h>
#include <linux/dma-map-ops.h>
#include <linux/efi.h>
+#include <linux/hugetlb.h>
#include <linux/ima.h>
#include <linux/init_ohci1394_dma.h>
#include <linux/initrd.h>
@@ -18,21 +19,19 @@
#include <linux/memblock.h>
#include <linux/panic_notifier.h>
#include <linux/pci.h>
+#include <linux/random.h>
#include <linux/root_dev.h>
-#include <linux/hugetlb.h>
-#include <linux/tboot.h>
-#include <linux/usb/xhci-dbgp.h>
#include <linux/static_call.h>
#include <linux/swiotlb.h>
-#include <linux/random.h>
+#include <linux/tboot.h>
+#include <linux/usb/xhci-dbgp.h>
+#include <linux/vmalloc.h>
#include <uapi/linux/mount.h>
#include <xen/xen.h>
#include <asm/apic.h>
-#include <asm/efi.h>
-#include <asm/numa.h>
#include <asm/bios_ebda.h>
#include <asm/bugs.h>
#include <asm/cacheinfo.h>
@@ -47,18 +46,16 @@
#include <asm/mce.h>
#include <asm/memtype.h>
#include <asm/mtrr.h>
-#include <asm/realmode.h>
+#include <asm/nmi.h>
+#include <asm/numa.h>
#include <asm/olpc_ofw.h>
#include <asm/pci-direct.h>
#include <asm/prom.h>
#include <asm/proto.h>
+#include <asm/realmode.h>
#include <asm/thermal.h>
#include <asm/unwind.h>
#include <asm/vsyscall.h>
-#include <linux/vmalloc.h>
-#if defined(CONFIG_X86_LOCAL_APIC)
-#include <asm/nmi.h>
-#endif
/*
* max_low_pfn_mapped: highest directly mapped pfn < 4 GB
@@ -152,6 +149,13 @@ int bootloader_type, bootloader_version;
static const struct ctl_table x86_sysctl_table[] = {
{
+ .procname = "unknown_nmi_panic",
+ .data = &unknown_nmi_panic,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {
.procname = "panic_on_unrecovered_nmi",
.data = &panic_on_unrecovered_nmi,
.maxlen = sizeof(int),
@@ -186,15 +190,6 @@ static const struct ctl_table x86_sysctl_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
-#if defined(CONFIG_X86_LOCAL_APIC)
- {
- .procname = "unknown_nmi_panic",
- .data = &unknown_nmi_panic,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec,
- },
-#endif
#if defined(CONFIG_ACPI_SLEEP)
{
.procname = "acpi_video_flags",
generated by cgit (git 2.34.1) at 2025-09-06 09:42:49 +0000