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powerpc/mce: Avoid using irq_work_queue() in realmode

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In realmode mce handler we use irq_work_queue() to defer
the processing of mce events, irq_work_queue() can only
be called when translation is enabled because it touches
memory outside RMA, hence we enable translation before
calling irq_work_queue and disable on return, though it
is not safe to do in realmode.

To avoid this, program the decrementer and call the event
processing functions from timer handler.

Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com
This commit is contained in:
Ganesh Goudar 2022-01-20 17:49:31 +05:30 committed by Michael Ellerman
parent 0a182611d1
commit cc15ff3275
8 changed files with 53 additions and 59 deletions
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2
arch/powerpc/include/asm/machdep.h
View File

@ -94,6 +94,8 @@ struct machdep_calls {
/* Called during machine check exception to retrive fixup address. */
bool (*mce_check_early_recovery)(struct pt_regs *regs);
void (*machine_check_log_err)(void);
/* Motherboard/chipset features. This is a kind of general purpose
* hook used to control some machine specific features (like reset
* lines, chip power control, etc...).

13
arch/powerpc/include/asm/mce.h
View File

@ -235,8 +235,21 @@ extern void machine_check_print_event_info(struct machine_check_event *evt,
unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr);
extern void mce_common_process_ue(struct pt_regs *regs,
struct mce_error_info *mce_err);
void mce_irq_work_queue(void);
int mce_register_notifier(struct notifier_block *nb);
int mce_unregister_notifier(struct notifier_block *nb);
#ifdef CONFIG_PPC_BOOK3S_64
void mce_run_irq_context_handlers(void);
#else
static inline void mce_run_irq_context_handlers(void) { };
#endif /* CONFIG_PPC_BOOK3S_64 */
#ifdef CONFIG_PPC_BOOK3S_64
void set_mce_pending_irq_work(void);
void clear_mce_pending_irq_work(void);
#endif /* CONFIG_PPC_BOOK3S_64 */
#ifdef CONFIG_PPC_BOOK3S_64
void flush_and_reload_slb(void);
void flush_erat(void);

1
arch/powerpc/include/asm/paca.h
View File

@ -288,6 +288,7 @@ struct paca_struct {
#endif
#ifdef CONFIG_PPC_BOOK3S_64
struct mce_info *mce_info;
u8 mce_pending_irq_work;
#endif /* CONFIG_PPC_BOOK3S_64 */
} ____cacheline_aligned;

60
arch/powerpc/kernel/mce.c
View File

@ -28,19 +28,9 @@
#include "setup.h"
static void machine_check_process_queued_event(struct irq_work *work);
static void machine_check_ue_irq_work(struct irq_work *work);
static void machine_check_ue_event(struct machine_check_event *evt);
static void machine_process_ue_event(struct work_struct *work);
static struct irq_work mce_event_process_work = {
.func = machine_check_process_queued_event,
};
static struct irq_work mce_ue_event_irq_work = {
.func = machine_check_ue_irq_work,
};
static DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
@ -89,6 +79,13 @@ static void mce_set_error_info(struct machine_check_event *mce,
}
}
void mce_irq_work_queue(void)
{
/* Raise decrementer interrupt */
arch_irq_work_raise();
set_mce_pending_irq_work();
}
/*
* Decode and save high level MCE information into per cpu buffer which
* is an array of machine_check_event structure.
@ -217,7 +214,7 @@ void release_mce_event(void)
get_mce_event(NULL, true);
}
static void machine_check_ue_irq_work(struct irq_work *work)
static void machine_check_ue_work(void)
{
schedule_work(&mce_ue_event_work);
}
@ -239,7 +236,7 @@ static void machine_check_ue_event(struct machine_check_event *evt)
evt, sizeof(*evt));
/* Queue work to process this event later. */
irq_work_queue(&mce_ue_event_irq_work);
mce_irq_work_queue();
}
/*
@ -249,7 +246,6 @@ void machine_check_queue_event(void)
{
int index;
struct machine_check_event evt;
unsigned long msr;
if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
return;
@ -263,20 +259,7 @@ void machine_check_queue_event(void)
memcpy(&local_paca->mce_info->mce_event_queue[index],
&evt, sizeof(evt));
/*
* Queue irq work to process this event later. Before
* queuing the work enable translation for non radix LPAR,
* as irq_work_queue may try to access memory outside RMO
* region.
*/
if (!radix_enabled() && firmware_has_feature(FW_FEATURE_LPAR)) {
msr = mfmsr();
mtmsr(msr | MSR_IR | MSR_DR);
irq_work_queue(&mce_event_process_work);
mtmsr(msr);
} else {
irq_work_queue(&mce_event_process_work);
}
mce_irq_work_queue();
}
void mce_common_process_ue(struct pt_regs *regs,
@ -338,7 +321,7 @@ static void machine_process_ue_event(struct work_struct *work)
* process pending MCE event from the mce event queue. This function will be
* called during syscall exit.
*/
static void machine_check_process_queued_event(struct irq_work *work)
static void machine_check_process_queued_event(void)
{
int index;
struct machine_check_event *evt;
@ -363,6 +346,27 @@ static void machine_check_process_queued_event(struct irq_work *work)
}
}
void set_mce_pending_irq_work(void)
{
local_paca->mce_pending_irq_work = 1;
}
void clear_mce_pending_irq_work(void)
{
local_paca->mce_pending_irq_work = 0;
}
void mce_run_irq_context_handlers(void)
{
if (unlikely(local_paca->mce_pending_irq_work)) {
if (ppc_md.machine_check_log_err)
ppc_md.machine_check_log_err();
machine_check_process_queued_event();
machine_check_ue_work();
clear_mce_pending_irq_work();
}
}
void machine_check_print_event_info(struct machine_check_event *evt,
bool user_mode, bool in_guest)
{

2
arch/powerpc/kernel/time.c
View File

@ -70,6 +70,7 @@
#include <asm/vdso_datapage.h>
#include <asm/firmware.h>
#include <asm/asm-prototypes.h>
#include <asm/mce.h>
/* powerpc clocksource/clockevent code */
@ -638,6 +639,7 @@ DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt)
if (test_irq_work_pending()) {
clear_irq_work_pending();
mce_run_irq_context_handlers();
irq_work_run();
}

1
arch/powerpc/platforms/pseries/pseries.h
View File

@ -21,6 +21,7 @@ struct pt_regs;
extern int pSeries_system_reset_exception(struct pt_regs *regs);
extern int pSeries_machine_check_exception(struct pt_regs *regs);
extern long pseries_machine_check_realmode(struct pt_regs *regs);
void pSeries_machine_check_log_err(void);
#ifdef CONFIG_SMP
extern void smp_init_pseries(void);

32
arch/powerpc/platforms/pseries/ras.c
View File

@ -23,11 +23,6 @@ static DEFINE_SPINLOCK(ras_log_buf_lock);
static int ras_check_exception_token;
static void mce_process_errlog_event(struct irq_work *work);
static struct irq_work mce_errlog_process_work = {
.func = mce_process_errlog_event,
};
#define EPOW_SENSOR_TOKEN 9
#define EPOW_SENSOR_INDEX 0
@ -745,7 +740,6 @@ static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp)
struct pseries_errorlog *pseries_log;
struct pseries_mc_errorlog *mce_log = NULL;
int disposition = rtas_error_disposition(errp);
unsigned long msr;
u8 error_type;
if (!rtas_error_extended(errp))
@ -759,40 +753,16 @@ static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp)
error_type = mce_log->error_type;
disposition = mce_handle_err_realmode(disposition, error_type);
/*
* Enable translation as we will be accessing per-cpu variables
* in save_mce_event() which may fall outside RMO region, also
* leave it enabled because subsequently we will be queuing work
* to workqueues where again per-cpu variables accessed, besides
* fwnmi_release_errinfo() crashes when called in realmode on
* pseries.
* Note: All the realmode handling like flushing SLB entries for
* SLB multihit is done by now.
*/
out:
msr = mfmsr();
mtmsr(msr | MSR_IR | MSR_DR);
disposition = mce_handle_err_virtmode(regs, errp, mce_log,
disposition);
/*
* Queue irq work to log this rtas event later.
* irq_work_queue uses per-cpu variables, so do this in virt
* mode as well.
*/
irq_work_queue(&mce_errlog_process_work);
mtmsr(msr);
return disposition;
}
/*
* Process MCE rtas errlog event.
*/
static void mce_process_errlog_event(struct irq_work *work)
void pSeries_machine_check_log_err(void)
{
struct rtas_error_log *err;

1
arch/powerpc/platforms/pseries/setup.c
View File

@ -1086,6 +1086,7 @@ define_machine(pseries) {
.system_reset_exception = pSeries_system_reset_exception,
.machine_check_early = pseries_machine_check_realmode,
.machine_check_exception = pSeries_machine_check_exception,
.machine_check_log_err = pSeries_machine_check_log_err,
#ifdef CONFIG_KEXEC_CORE
.machine_kexec = pSeries_machine_kexec,
.kexec_cpu_down = pseries_kexec_cpu_down,