Messages in this thread Patch in this message | | | From | Matt Fleming <> | Subject | [PATCH 2/5] x86/efi: Map RAM into the identity page table for mixed mode | Date | Sat, 14 Nov 2015 22:00:48 +0000 |
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We are relying on the pre-existing mappings in 'trampoline_pgd' when accessing function arguments in the EFI mixed mode thunking code.
Instead let's map memory explicitly so that things will continue to work when we move to a separate page table in the future.
Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> --- arch/x86/platform/efi/efi_64.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index c8b58ac47b77..634536034e32 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -144,6 +144,7 @@ void efi_sync_low_kernel_mappings(void) int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) { unsigned long pfn, text; + efi_memory_desc_t *md; struct page *page; unsigned npages; pgd_t *pgd; @@ -200,6 +201,25 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */ + /* + * Map all of RAM so that we can access arguments in the 1:1 + * mapping when making EFI runtime calls. + */ + for_each_efi_memory_desc(&memmap, md) { + if (md->type != EFI_CONVENTIONAL_MEMORY && + md->type != EFI_LOADER_DATA && + md->type != EFI_LOADER_CODE) + continue; + + pfn = md->phys_addr >> PAGE_SHIFT; + npages = md->num_pages; + + if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, 0)) { + pr_err("Failed to map 1:1 memory\n"); + return 1; + } + } + return 0; } -- 2.6.2
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