freebsd-dev/sys/powerpc/powernv/opal_hmi.c
Brandon Bergren 9367fb301c [PowerPC] Fix panic when attempting to handle an HMI from an idle thread
In IRC, sfs_ finally managed to get a good trace of a kernel panic that was
happening when attempting to use webengine.

As it turns out, we were using vtophys() from interrupt context on an idle
thread in opal_hmi_handler2().

Since this involves locking the kernel pmap on PPC64 at the moment, this
ended up tripping a KASSERT in mtx_lock(), which then caused a parallel
panic stampede.

So, avoid this by preallocating the flags variable and storing it in PCPU.

Fixes "panic: mtx_lock() by idle thread 0x... on sleep mutex kernelpmap".

Differential Revision:	https://reviews.freebsd.org/D22962
2019-12-30 02:56:47 +00:00

147 lines
3.7 KiB
C

/*-
* Copyright (c) 2019 Justin Hibbits
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/endian.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <machine/spr.h>
#include <machine/trap.h>
#include "opal.h"
struct opal_hmi_event {
uint8_t version;
uint8_t severity;
uint8_t type;
uint8_t disposition;
uint8_t rsvd_1[4];
uint64_t hmer;
uint64_t tfmr;
union {
struct {
uint8_t xstop_type;
uint8_t rsvd_2[3];
uint32_t xstop_reason;
union {
uint32_t pir;
uint32_t chip_id;
};
};
};
};
#define HMI_DISP_RECOVERED 0
#define HMI_DISP_NOT_RECOVERED 1
static void
opal_hmi_event_handler(void *unused, struct opal_msg *msg)
{
struct opal_hmi_event evt;
memcpy(&evt, &msg->params, sizeof(evt));
printf("Hypervisor Maintenance Event received"
"(Severity %d, type %d, HMER: %016lx).\n",
evt.severity, evt.type, evt.hmer);
if (evt.disposition == HMI_DISP_NOT_RECOVERED)
panic("Unrecoverable hypervisor maintenance exception on CPU %d",
evt.pir);
return;
}
static int
opal_hmi_handler2(struct trapframe *frame)
{
/*
* Use DMAP preallocated pcpu memory to handle
* the phys flags pointer.
*/
uint64_t *flags = PCPU_PTR(aim.opal_hmi_flags);
int err;
*flags = 0;
err = opal_call(OPAL_HANDLE_HMI2, DMAP_TO_PHYS((vm_offset_t)flags));
if (*flags & OPAL_HMI_FLAGS_TOD_TB_FAIL)
panic("TOD/TB recovery failure");
if (err == OPAL_SUCCESS)
return (0);
printf("HMI handler failed! OPAL error code: %d\n", err);
return (-1);
}
static int
opal_hmi_handler(struct trapframe *frame)
{
int err;
err = opal_call(OPAL_HANDLE_HMI);
if (err == OPAL_SUCCESS)
return (0);
printf("HMI handler failed! OPAL error code: %d\n", err);
return (-1);
}
static void
opal_setup_hmi(void *data)
{
/* This only works for OPAL, so first make sure we have it. */
if (opal_check() != 0)
return;
if (opal_call(OPAL_CHECK_TOKEN, OPAL_HANDLE_HMI2) == OPAL_TOKEN_PRESENT)
hmi_handler = opal_hmi_handler2;
else if (opal_call(OPAL_CHECK_TOKEN, OPAL_HANDLE_HMI) == OPAL_TOKEN_PRESENT)
hmi_handler = opal_hmi_handler;
else {
printf("Warning: No OPAL HMI handler found.\n");
return;
}
EVENTHANDLER_REGISTER(OPAL_HMI_EVT, opal_hmi_event_handler, NULL,
EVENTHANDLER_PRI_ANY);
if (bootverbose)
printf("Installed OPAL HMI handler.\n");
}
SYSINIT(opal_setup_hmi, SI_SUB_CPU, SI_ORDER_ANY, opal_setup_hmi, NULL);