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Commit a774635d authored by Li RongQing's avatar Li RongQing Committed by Thomas Gleixner
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x86/apic: Fix signedness bug in APIC ID validity checks 



The APIC ID as parsed from ACPI MADT is validity checked with the
apic->apic_id_valid() callback, which depends on the selected APIC type.

For non X2APIC types APIC IDs >= 0xFF are invalid, but values > 0x7FFFFFFF
are detected as valid. This happens because the 'apicid' argument of the
apic_id_valid() callback is type 'int'. So the resulting comparison

   apicid < 0xFF

evaluates to true for all unsigned int values > 0x7FFFFFFF which are handed
to default_apic_id_valid(). As a consequence, invalid APIC IDs in !X2APIC
mode are considered valid and accounted as possible CPUs.

Change the apicid argument type of the apic_id_valid() callback to u32 so
the evaluation is unsigned and returns the correct result.

[ tglx: Massaged changelog ]

Signed-off-by: default avatarLi RongQing <lirongqing@baidu.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: jgross@suse.com
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/1523322966-10296-1-git-send-email-lirongqing@baidu.com
parent d94a155c

arch/x86/include/asm/apic.h

+2 −2
Original line number Diff line number Diff line
@@ -319,7 +319,7 @@ struct apic { 
	/* Probe, setup and smpboot functions */

	int	(*probe)(void);

	int	(*acpi_madt_oem_check)(char *oem_id, char *oem_table_id);

	int	(*apic_id_valid)(int apicid);

	int	(*apic_id_valid)(u32 apicid);

	int	(*apic_id_registered)(void);



	bool	(*check_apicid_used)(physid_mask_t *map, int apicid);
@@ -492,7 +492,7 @@ static inline unsigned int read_apic_id(void) 
	return apic->get_apic_id(reg);

}



extern int default_apic_id_valid(int apicid);

extern int default_apic_id_valid(u32 apicid);

extern int default_acpi_madt_oem_check(char *, char *);

extern void default_setup_apic_routing(void);

arch/x86/kernel/acpi/boot.c

+8 −5
Original line number Diff line number Diff line
@@ -200,7 +200,7 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end) 
{

	struct acpi_madt_local_x2apic *processor = NULL;

#ifdef CONFIG_X86_X2APIC

	int apic_id;

	u32 apic_id;

	u8 enabled;

#endif
@@ -222,9 +222,12 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end) 
	 * to not preallocating memory for all NR_CPUS

	 * when we use CPU hotplug.

	 */

	if (!apic->apic_id_valid(apic_id) && enabled)

		printk(KERN_WARNING PREFIX "x2apic entry ignored\n");

	else

	if (!apic->apic_id_valid(apic_id)) {

		if (enabled)

			pr_warn(PREFIX "x2apic entry ignored\n");

		return 0;

	}



	acpi_register_lapic(apic_id, processor->uid, enabled);

#else

	printk(KERN_WARNING PREFIX "x2apic entry ignored\n");

arch/x86/kernel/apic/apic_common.c

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ int default_check_phys_apicid_present(int phys_apicid) 
	return physid_isset(phys_apicid, phys_cpu_present_map);

}



int default_apic_id_valid(int apicid)

int default_apic_id_valid(u32 apicid)

{

	return (apicid < 255);

}

arch/x86/kernel/apic/apic_numachip.c

+1 −1
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ static u32 numachip2_set_apic_id(unsigned int id) 
	return id << 24;

}



static int numachip_apic_id_valid(int apicid)

static int numachip_apic_id_valid(u32 apicid)

{

	/* Trust what bootloader passes in MADT */

	return 1;

arch/x86/kernel/apic/x2apic.h

+1 −1
Original line number Diff line number Diff line 
/* Common bits for X2APIC cluster/physical modes. */



int x2apic_apic_id_valid(int apicid);

int x2apic_apic_id_valid(u32 apicid);

int x2apic_apic_id_registered(void);

void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);

unsigned int x2apic_get_apic_id(unsigned long id);