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Commit 05c3dc2c authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
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x86, ioapic: Fix non atomic allocation with interrupts disabled 



Impact: fix possible race

save_mask_IO_APIC_setup() was using non atomic memory allocation while getting
called with interrupts disabled. Fix this by splitting this into two different
function. Allocation part save_IO_APIC_setup() now happens before
disabling interrupts.

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 29b61be6

arch/x86/include/asm/io_apic.h

+2 −1
Original line number Original line Diff line number Diff line
@@ -162,7 +162,8 @@ extern int (*ioapic_renumber_irq)(int ioapic, int irq); 
extern void ioapic_init_mappings(void);

extern void ioapic_init_mappings(void);





#ifdef CONFIG_X86_64

#ifdef CONFIG_X86_64

extern int save_mask_IO_APIC_setup(void);

extern int save_IO_APIC_setup(void);

extern void mask_IO_APIC_setup(void);

extern void restore_IO_APIC_setup(void);

extern void restore_IO_APIC_setup(void);

extern void reinit_intr_remapped_IO_APIC(int);

extern void reinit_intr_remapped_IO_APIC(int);

#endif

#endif

arch/x86/kernel/apic/apic.c

+6 −5
Original line number Original line Diff line number Diff line
@@ -1334,15 +1334,16 @@ void __init enable_IR_x2apic(void) 
		return;

		return;

	}

	}





	local_irq_save(flags);

	ret = save_IO_APIC_setup();

	mask_8259A();



	ret = save_mask_IO_APIC_setup();

	if (ret) {

	if (ret) {

		pr_info("Saving IO-APIC state failed: %d\n", ret);

		pr_info("Saving IO-APIC state failed: %d\n", ret);

		goto end;

		goto end;

	}

	}





	local_irq_save(flags);

	mask_IO_APIC_setup();

	mask_8259A();



	ret = enable_intr_remapping(1);

	ret = enable_intr_remapping(1);





	if (ret && x2apic_preenabled) {

	if (ret && x2apic_preenabled) {
@@ -1367,10 +1368,10 @@ void __init enable_IR_x2apic(void) 
	else

	else

		reinit_intr_remapped_IO_APIC(x2apic_preenabled);

		reinit_intr_remapped_IO_APIC(x2apic_preenabled);





end:

	unmask_8259A();

	unmask_8259A();

	local_irq_restore(flags);

	local_irq_restore(flags);





end:

	if (!ret) {

	if (!ret) {

		if (!x2apic_preenabled)

		if (!x2apic_preenabled)

			pr_info("Enabled x2apic and interrupt-remapping\n");

			pr_info("Enabled x2apic and interrupt-remapping\n");

arch/x86/kernel/apic/io_apic.c

+23 −11
Original line number Original line Diff line number Diff line
@@ -853,9 +853,9 @@ __setup("pirq=", ioapic_pirq_setup); 
static struct IO_APIC_route_entry *early_ioapic_entries[MAX_IO_APICS];

static struct IO_APIC_route_entry *early_ioapic_entries[MAX_IO_APICS];





/*

/*

 * Saves and masks all the unmasked IO-APIC RTE's

 * Saves all the IO-APIC RTE's

 */

 */

int save_mask_IO_APIC_setup(void)

int save_IO_APIC_setup(void)

{

{

	union IO_APIC_reg_01 reg_01;

	union IO_APIC_reg_01 reg_01;

	unsigned long flags;

	unsigned long flags;
@@ -880,16 +880,9 @@ int save_mask_IO_APIC_setup(void) 
	}

	}





	for (apic = 0; apic < nr_ioapics; apic++)

	for (apic = 0; apic < nr_ioapics; apic++)

		for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {

		for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)

			struct IO_APIC_route_entry entry;

			early_ioapic_entries[apic][pin] =



			entry = early_ioapic_entries[apic][pin] =

				ioapic_read_entry(apic, pin);

				ioapic_read_entry(apic, pin);

			if (!entry.mask) {

				entry.mask = 1;

				ioapic_write_entry(apic, pin, entry);

			}

		}





	return 0;

	return 0;
@@ -902,6 +895,25 @@ int save_mask_IO_APIC_setup(void) 
	return -ENOMEM;

	return -ENOMEM;

}

}





void mask_IO_APIC_setup(void)

{

	int apic, pin;



	for (apic = 0; apic < nr_ioapics; apic++) {

		if (!early_ioapic_entries[apic])

			break;

		for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {

			struct IO_APIC_route_entry entry;



			entry = early_ioapic_entries[apic][pin];

			if (!entry.mask) {

				entry.mask = 1;

				ioapic_write_entry(apic, pin, entry);

			}

		}

	}

}



void restore_IO_APIC_setup(void)

void restore_IO_APIC_setup(void)

{

{

	int apic, pin;

	int apic, pin;