Messages in this thread | | | Date | Fri, 27 Mar 2015 07:01:10 +0800 | From | Hanjun Guo <> | Subject | Re: [patch v11 12/23] ARM64 / ACPI: Parse MADT for SMP initialization |
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On 2015年03月27日 05:12, Will Deacon wrote: > On Thu, Mar 26, 2015 at 07:48:50PM +0000, Hanjun Guo wrote: >> On 2015年03月26日 23:15, Will Deacon wrote: >>> commit 8ef320319592693f4a6286d80df210fd47b3e356 >>> Author: Will Deacon <will.deacon@arm.com> >>> Date: Thu Mar 26 15:09:20 2015 +0000 >>> >>> ARM64 / ACPI: fix usage of acpi_map_gic_cpu_interface >>> >>> acpi_parse_gic_cpu_interface calls acpi_map_gic_cpu_interface by both >>> passing a 32-bit value in the u8 enabled parameter and then subsequently >>> ignoring its return value. >>> >>> Sort it out. >>> >>> Reported-by: Catalin Marinas <catalin.marinas@arm.com> >>> Signed-off-by: Will Deacon <will.deacon@arm.com> >>> >>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c >>> index cd60329da8c4..07649e413244 100644 >>> --- a/arch/arm64/kernel/acpi.c >>> +++ b/arch/arm64/kernel/acpi.c >>> @@ -103,9 +103,12 @@ void __init __acpi_unmap_table(char *map, unsigned long size) >>> * >>> * Returns the logical cpu number which maps to MPIDR >>> */ >>> -static int __init acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled) >>> +static int __init >>> +acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor) >> >> How about just replace u8 with u32? This function has its purpose to >> be lived, on x86/ia64, ACPI core will get the physcal cpu ID via >> ACPI handle, then pass it to the arch specific mapping function >> to map the physcal cpu ID with logical cpu ID for the new added >> CPU, so when ACPI based CPU hot-plug is introduced on ARM64, we >> need to go back to that solution. > > If/when that happens, we can change things then. Right now, this is a static > function with one caller. One step at a time, please. > >>> { >>> int i; >>> + u64 mpidr = processor->arm_mpidr & MPIDR_HWID_BITMASK; >>> + bool enabled = !!(processor->flags & ACPI_MADT_ENABLED); >>> >>> if (mpidr == INVALID_HWID) { >>> pr_info("Skip MADT cpu entry with invalid MPIDR\n"); >>> @@ -178,11 +181,7 @@ acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header, >>> return -EINVAL; >>> >>> acpi_table_print_madt_entry(header); >>> - >>> - acpi_map_gic_cpu_interface(processor->arm_mpidr & MPIDR_HWID_BITMASK, >>> - processor->flags & ACPI_MADT_ENABLED); >>> - >>> - return 0; >>> + return acpi_map_gic_cpu_interface(processor); >> >> I don't think we need to return the error value here, in ACPI >> core, it will stop the MADT scanning once it returned the error >> value, but actually we can skip some disabled GICC (cpu) entries >> and find all the enabled ones in MADT, for example, >> >> cpu0 entry, with flag enabled >> cpu1 entry, disabled - if we return the error value, table scanning >> will stop >> cpu2 entry, enabled - and this cpu will be ignored > > Then send me a patch making acpi_map_gic_cpu_interface have a void return > type. Ignoring the return type is usually a good way to introduce subtle > bugs.
OK, I will, and I will cleanup the comments for this function too.
Need some sleep first...
Thanks Hanjun
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