With all support in place, enable fadump by exporting the
"ibm,configure-kernel-dump" RTAS call in the device tree.
Presence of "ibm,configure-kernel-dump" tells the kernel that the
platform (QEMU) supports fadump.
Pass "fadump=on" to enable Linux to use firmware assisted dump.
Logs of a linux boot with firmware assisted dump:
./build/qemu-system-ppc64 -M pseries,x-vof=on --cpu power10 --smp 4 -m 4G
-kernel some-vmlinux -initrd some-initrd -append "debug fadump=on
crashkernel=1G" -nographic
[ 0.000000] random: crng init done
[ 0.000000] fadump: Reserved 1024MB of memory at 0x00000040000000
(System RAM: 4096MB)
...
[ 1.084686] rtas fadump: Registration is successful!
...
# cat /sys/kernel/debug/powerpc/fadump_region
CPU :[0x00000040000000-0x000000400013d3] 0x13d4 bytes, Dumped: 0x0
HPTE:[0x000000400013d4-0x000000400013d3] 0x0 bytes, Dumped: 0x0
DUMP: Src: 0x00000000000000, Dest: 0x00000040010000, Size: 0x40000000,
Dumped: 0x0 bytes
[0x000000fffff800-0x000000ffffffff]: cmdline append: ''
# echo c > /proc/sysrq-trigger
The fadump boot after crash:
[ 0.000000] rtas fadump: Firmware-assisted dump is active.
[ 0.000000] fadump: Updated cmdline: debug fadump=on crashkernel=1G
[ 0.000000] fadump: Firmware-assisted dump is active.
[ 0.000000] fadump: Reserving 3072MB of memory at 0x00000040000000 for
preserving crash data
....
# file /proc/vmcore
/proc/vmcore: ELF 64-bit LSB core file, 64-bit PowerPC or cisco 7500,
OpenPOWER ELF V2 ABI, version 1 (SYSV), SVR4-style
Analysing the vmcore with crash-utility:
KERNEL: vmlinux-6.14-rc2
DUMPFILE: vmcore-a64dcfb451e2-nocma
CPUS: 4
DATE: Thu Jan 1 05:30:00 IST 1970
UPTIME: 00:00:30
LOAD AVERAGE: 0.74, 0.21, 0.07
TASKS: 94
NODENAME: buildroot
RELEASE: 6.14.0-rc2+
VERSION: #1 SMP Wed Feb 12 06:49:59 CST 2025
MACHINE: ppc64le (1000 Mhz)
MEMORY: 4 GB
PANIC: "Kernel panic - not syncing: sysrq triggered crash"
PID: 270
COMMAND: "sh"
TASK: c000000009e7cc00 [THREAD_INFO: c000000009e7cc00]
CPU: 3
STATE: TASK_RUNNING (PANIC)
Signed-off-by: Aditya Gupta <[email protected]>
---
hw/ppc/spapr_rtas.c | 6 +++++-
include/hw/ppc/spapr.h | 3 ++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 0aca4270aee8..bd2ed16a46e3 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -692,7 +692,7 @@ static void trigger_fadump_boot(target_ulong spapr_retcode)
}
/* Papr Section 7.4.9 ibm,configure-kernel-dump RTAS call */
-static __attribute((unused)) void rtas_configure_kernel_dump(PowerPCCPU *cpu,
+static void rtas_configure_kernel_dump(PowerPCCPU *cpu,
SpaprMachineState *spapr,
uint32_t token, uint32_t nargs,
target_ulong args,
@@ -1109,6 +1109,10 @@ static void core_rtas_register_types(void)
spapr_rtas_register(RTAS_IBM_NMI_INTERLOCK, "ibm,nmi-interlock",
rtas_ibm_nmi_interlock);
+ /* Register Fadump rtas call */
+ spapr_rtas_register(RTAS_CONFIGURE_KERNEL_DUMP,
"ibm,configure-kernel-dump",
+ rtas_configure_kernel_dump);
+
qtest_set_command_cb(spapr_qtest_callback);
}
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index fa63008e57ec..bde3bdc4b80c 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -768,8 +768,9 @@ void push_sregs_to_kvm_pr(SpaprMachineState *spapr);
#define RTAS_IBM_SUSPEND_ME (RTAS_TOKEN_BASE + 0x2A)
#define RTAS_IBM_NMI_REGISTER (RTAS_TOKEN_BASE + 0x2B)
#define RTAS_IBM_NMI_INTERLOCK (RTAS_TOKEN_BASE + 0x2C)
+#define RTAS_CONFIGURE_KERNEL_DUMP (RTAS_TOKEN_BASE + 0x2D)
-#define RTAS_TOKEN_MAX (RTAS_TOKEN_BASE + 0x2D)
+#define RTAS_TOKEN_MAX (RTAS_TOKEN_BASE + 0x2E)
/* Fadump commands */
#define FADUMP_CMD_REGISTER 1
--
2.48.1
