Messages in this thread | | | Date | Wed, 04 Feb 2015 17:48:05 +0800 | From | Hanjun Guo <> | Subject | Re: [PATCH v8 14/21] ACPI / processor: Make it possible to get CPU hardware ID via GICC |
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On 2015年02月04日 04:09, Catalin Marinas wrote: > On Tue, Feb 03, 2015 at 02:17:49PM +0000, Mark Rutland wrote: >> On Mon, Feb 02, 2015 at 12:45:42PM +0000, Hanjun Guo wrote: >>> Introduce a new function map_gicc_mpidr() to allow MPIDRs to be obtained >>> from the GICC Structure introduced by ACPI 5.1. >>> >>> MPIDR is the CPU hardware ID as local APIC ID on x86 platform, so we use >>> MPIDR not the GIC CPU interface ID to identify CPUs. >>> >>> Further steps would typedef a phys_id_t for in arch code(with >>> appropriate size and a corresponding invalid value, say ~0) and use that >>> instead of an int in drivers/acpi/processor_core.c to store phys_id, then >>> no need for mpidr packing. >> >> I don't understand why we don't fix this now, and I'm very worried that >> this patch leaves much potential for FW bugs due to potential Linux >> bugs. >> >> Having a function called cpu_physical_id which _does not_ return a >> physical ID makes no sense to me. Any time we really need a physical >> ID, we're still going to have to unpack it (in an architecture-specific >> manner). > > Do you mean something like this? Only briefly tested on Juno and I may > have missed other calls:
Thanks, I think it is Mark's suggestion (and also Lorenzo's)
> > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index ea4d2b35c57b..4fafd62b1b86 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -49,33 +49,12 @@ static inline void enable_acpi(void) > acpi_noirq = 0; > } > > -/* MPIDR value provided in GICC structure is 64 bits, but the > - * existing phys_id (CPU hardware ID) using in acpi processor > - * driver is 32-bit, to conform to the same datatype we need > - * to repack the GICC structure MPIDR. > - * > - * bits other than following 32 bits are defined as 0, so it > - * will be no information lost after repacked. > - * > - * Bits [0:7] Aff0; > - * Bits [8:15] Aff1; > - * Bits [16:23] Aff2; > - * Bits [32:39] Aff3; > - */ > -static inline u32 pack_mpidr(u64 mpidr) > -{ > - return (u32) ((mpidr & 0xff00000000) >> 8) | mpidr; > -} > - > /* > * The ACPI processor driver for ACPI core code needs this macro > * to find out this cpu was already mapped (mapping from CPU hardware > * ID to CPU logical ID) or not. > - * > - * cpu_logical_map(cpu) is the mapping of MPIDR and the logical cpu, > - * and MPIDR is the cpu hardware ID we needed to pack. > */ > -#define cpu_physical_id(cpu) pack_mpidr(cpu_logical_map(cpu)) > +#define cpu_physical_id(cpu) cpu_logical_map(cpu) > > /* > * It's used from ACPI core in kdump to boot UP system with SMP kernel, > diff --git a/arch/arm64/include/asm/smp_plat.h b/arch/arm64/include/asm/smp_plat.h > index 59e282311b58..a492276e008d 100644 > --- a/arch/arm64/include/asm/smp_plat.h > +++ b/arch/arm64/include/asm/smp_plat.h > @@ -40,4 +40,6 @@ static inline u32 mpidr_hash_size(void) > extern u64 __cpu_logical_map[NR_CPUS]; > #define cpu_logical_map(cpu) __cpu_logical_map[cpu] > > +typedef u64 cpuid_t;
I think cpuid_t is a little confused because people may recognize it as cpu logical id, its original meaning is the physical cpu ID, so how about:
typedef u64 phys_id_t; ?
Thanks Hanjun
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