Messages in this thread Patch in this message | | | Subject | [PATCH][REVISED] x86: efi/e820 table merge fix | From | Cliff Wickman <> | Date | Wed, 17 Jun 2009 14:24:00 -0500 |
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From: Cliff Wickman <cpw@sgi.com>
This patch causes all the RAM reservations of EFI_RESERVED_TYPE to be recorded in the e820 table as type E820_RESERVED.
(A bit of clarification was added in the comment, per Peter and Huang.)
Without this patch EFI_RESERVED_TYPE memory reservations that are also of attribute type EFI_MEMORY_WB are marked usable in the e820 table. That would cause a collision between kernel use and some reserver's use of this memory.
(An example use of this functionality is the UV system, which will access extremely large areas of (write-back) memory with a memory engine that allows a user to address beyond the processor's range. Such areas are reserved in the EFI table by the BIOS. Some loaders have a restricted number of entries possible in the e820 table, hence the need to record the reservations in the unrestricted EFI table.)
The call to do_add_efi_memmap() is only made if "add_efi_memmap" is specified on the kernel command line.
Diffed against 2.6.30-rc8
Signed-off-by: Cliff Wickman <cpw@sgi.com> --- arch/x86/kernel/efi.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-)
Index: linux/arch/x86/kernel/efi.c =================================================================== --- linux.orig/arch/x86/kernel/efi.c +++ linux/arch/x86/kernel/efi.c @@ -240,10 +240,39 @@ static void __init do_add_efi_memmap(voi unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; int e820_type; - if (md->attribute & EFI_MEMORY_WB) - e820_type = E820_RAM; - else + switch (md->type) { + case EFI_LOADER_CODE: + case EFI_LOADER_DATA: + case EFI_BOOT_SERVICES_CODE: + case EFI_BOOT_SERVICES_DATA: + case EFI_CONVENTIONAL_MEMORY: + /* + * make sure that memory that is not write-back does + * not enter the usable memory pool + */ + if (md->attribute & EFI_MEMORY_WB) + e820_type = E820_RAM; + else + e820_type = E820_RESERVED; + break; + case EFI_ACPI_RECLAIM_MEMORY: + e820_type = E820_ACPI; + break; + case EFI_ACPI_MEMORY_NVS: + e820_type = E820_NVS; + break; + case EFI_UNUSABLE_MEMORY: + e820_type = E820_UNUSABLE; + break; + default: + /* + * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE + * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO + * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE + */ e820_type = E820_RESERVED; + break; + } e820_add_region(start, size, e820_type); } sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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