Commit cc15ff32 authored by Ganesh Goudar's avatar Ganesh Goudar Committed by Michael Ellerman
Browse files

powerpc/mce: Avoid using irq_work_queue() in realmode 



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: default avatarGanesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com
parent 0a182611

arch/powerpc/include/asm/machdep.h

+2 −0
Original line number Diff line number Diff line
@@ -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...).

arch/powerpc/include/asm/mce.h

+13 −0
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/include/asm/paca.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/kernel/mce.c

+32 −28
Original line number Diff line number Diff line
@@ -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)

{

arch/powerpc/kernel/time.c

+2 −0
Original line number Diff line number Diff line
@@ -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();

	}