[tip: x86/platform] x86/platform/uv: Add more to secondary CPU kdump info

From: tip-bot2 for Georges Aureau
Date: Mon Apr 12 2021 - 13:49:05 EST


The following commit has been merged into the x86/platform branch of tip:

Commit-ID: 8f2aca40dd077f74e62982cd2669845f41ed0ac6
Gitweb: https://git.kernel.org/tip/8f2aca40dd077f74e62982cd2669845f41ed0ac6
Author: Georges Aureau <georges.aureau@xxxxxxx>
AuthorDate: Thu, 11 Mar 2021 09:10:28 -06:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Mon, 12 Apr 2021 19:42:10 +02:00

x86/platform/uv: Add more to secondary CPU kdump info

Add call to run_crash_ipi_callback() to gather more info of what the
secondary CPUs were doing to help with failure analysis.

Excerpt from Georges:

'It is only changing where crash secondaries will be stalling after
having taken care of properly laying down "crash note regs". Please
note that "crash note regs" are a key piece of data used by crash dump
debuggers to provide a reliable backtrace of running processors.'

Secondary change pursuant to

a5f526ecb075 ("CodingStyle: Inclusive Terminology"):

change master/slave to main/secondary.

[ bp: Massage commit message. ]

Signed-off-by: Georges Aureau <georges.aureau@xxxxxxx>
Signed-off-by: Mike Travis <mike.travis@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Steve Wahl <steve.wahl@xxxxxxx>
Link: https://lkml.kernel.org/r/20210311151028.82678-1-mike.travis@xxxxxxx
---
arch/x86/platform/uv/uv_nmi.c | 39 ++++++++++++++++++++--------------
1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index eafc530..f83810f 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -24,6 +24,7 @@
#include <asm/kdebug.h>
#include <asm/local64.h>
#include <asm/nmi.h>
+#include <asm/reboot.h>
#include <asm/traps.h>
#include <asm/uv/uv.h>
#include <asm/uv/uv_hub.h>
@@ -834,34 +835,42 @@ static void uv_nmi_touch_watchdogs(void)
touch_nmi_watchdog();
}

-static atomic_t uv_nmi_kexec_failed;
-
#if defined(CONFIG_KEXEC_CORE)
-static void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs)
+static atomic_t uv_nmi_kexec_failed;
+static void uv_nmi_kdump(int cpu, int main, struct pt_regs *regs)
{
+ /* Check if kdump kernel loaded for both main and secondary CPUs */
+ if (!kexec_crash_image) {
+ if (main)
+ pr_err("UV: NMI error: kdump kernel not loaded\n");
+ return;
+ }
+
/* Call crash to dump system state */
- if (master) {
+ if (main) {
pr_emerg("UV: NMI executing crash_kexec on CPU%d\n", cpu);
crash_kexec(regs);

- pr_emerg("UV: crash_kexec unexpectedly returned, ");
+ pr_emerg("UV: crash_kexec unexpectedly returned\n");
atomic_set(&uv_nmi_kexec_failed, 1);
- if (!kexec_crash_image) {
- pr_cont("crash kernel not loaded\n");
- return;
+
+ } else { /* secondary */
+
+ /* If kdump kernel fails, secondaries will exit this loop */
+ while (atomic_read(&uv_nmi_kexec_failed) == 0) {
+
+ /* Once shootdown cpus starts, they do not return */
+ run_crash_ipi_callback(regs);
+
+ mdelay(10);
}
- pr_cont("kexec busy, stalling cpus while waiting\n");
}
-
- /* If crash exec fails the slaves should return, otherwise stall */
- while (atomic_read(&uv_nmi_kexec_failed) == 0)
- mdelay(10);
}

#else /* !CONFIG_KEXEC_CORE */
-static inline void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs)
+static inline void uv_nmi_kdump(int cpu, int main, struct pt_regs *regs)
{
- if (master)
+ if (main)
pr_err("UV: NMI kdump: KEXEC not supported in this kernel\n");
atomic_set(&uv_nmi_kexec_failed, 1);
}