3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Li RongQing <lirongqing@xxxxxxxxx> commit a774635db5c430cbf21fa5d2f2df3d23aaa8e782 upstream. 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: Li RongQing <lirongqing@xxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: jgross@xxxxxxxx Cc: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: hpa@xxxxxxxxx Link: https://lkml.kernel.org/r/1523322966-10296-1-git-send-email-lirongqing@xxxxxxxxx [bwh: Backported to 3.16: - Drop change to xen_id_always_valid() - Adjust filenames, context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -288,7 +288,7 @@ struct apic { 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); u32 irq_delivery_mode; @@ -547,7 +547,7 @@ static inline unsigned int read_apic_id( return apic->get_apic_id(reg); } -static inline int default_apic_id_valid(int apicid) +static inline int default_apic_id_valid(u32 apicid) { return (apicid < 255); } --- a/arch/x86/include/asm/x2apic.h +++ b/arch/x86/include/asm/x2apic.h @@ -9,7 +9,7 @@ #include <asm/ipi.h> #include <linux/cpumask.h> -static int x2apic_apic_id_valid(int apicid) +static int x2apic_apic_id_valid(u32 apicid) { return 1; } --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -215,7 +215,7 @@ static int __init acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end) { struct acpi_madt_local_x2apic *processor = NULL; - int apic_id; + u32 apic_id; u8 enabled; processor = (struct acpi_madt_local_x2apic *)header; @@ -235,10 +235,13 @@ acpi_parse_x2apic(struct acpi_subtable_h * 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 - acpi_register_lapic(apic_id, enabled); + if (!apic->apic_id_valid(apic_id)) { + if (enabled) + pr_warn(PREFIX "x2apic entry ignored\n"); + return 0; + } + + acpi_register_lapic(apic_id, enabled); #else printk(KERN_WARNING PREFIX "x2apic entry ignored\n"); #endif --- a/arch/x86/kernel/apic/apic_numachip.c +++ b/arch/x86/kernel/apic/apic_numachip.c @@ -58,7 +58,7 @@ static unsigned int read_xapic_id(void) return get_apic_id(apic_read(APIC_ID)); } -static int numachip_apic_id_valid(int apicid) +static int numachip_apic_id_valid(u32 apicid) { /* Trust what bootloader passes in MADT */ return 1; --- a/arch/x86/kernel/apic/x2apic_uv_x.c +++ b/arch/x86/kernel/apic/x2apic_uv_x.c @@ -272,7 +272,7 @@ static void uv_send_IPI_all(int vector) uv_send_IPI_mask(cpu_online_mask, vector); } -static int uv_apic_id_valid(int apicid) +static int uv_apic_id_valid(u32 apicid) { return 1; }
