72 lines
2.6 KiB
Diff
72 lines
2.6 KiB
Diff
From: Matt Fleming <matt@codeblueprint.co.uk>
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Date: Fri, 27 Nov 2015 21:09:32 +0000
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Subject: [3/5] x86/efi: Map RAM into the identity page table for mixed mode
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Origin: https://git.kernel.org/cgit/linux/kernel/git/mfleming/efi.git/commit?id=b61a76f8850d2979550abc42d7e09154ebb8d785
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We are relying on the pre-existing mappings in 'trampoline_pgd'
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when accessing function arguments in the EFI mixed mode thunking
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code.
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Instead let's map memory explicitly so that things will continue
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to work when we move to a separate page table in the future.
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Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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Acked-by: Borislav Petkov <bp@suse.de>
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Cc: Andy Lutomirski <luto@amacapital.net>
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Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Cc: Toshi Kani <toshi.kani@hp.com>
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Cc: linux-efi@vger.kernel.org
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Link: http://lkml.kernel.org/r/1448658575-17029-4-git-send-email-matt@codeblueprint.co.uk
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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---
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arch/x86/platform/efi/efi_64.c | 20 ++++++++++++++++++++
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1 file changed, 20 insertions(+)
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diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
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index 5aa186db59e3..102976dda8c4 100644
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--- a/arch/x86/platform/efi/efi_64.c
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+++ b/arch/x86/platform/efi/efi_64.c
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@@ -144,6 +144,7 @@ void efi_sync_low_kernel_mappings(void)
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int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
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{
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unsigned long pfn, text;
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+ efi_memory_desc_t *md;
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struct page *page;
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unsigned npages;
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pgd_t *pgd;
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@@ -177,6 +178,25 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
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if (!IS_ENABLED(CONFIG_EFI_MIXED))
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return 0;
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+ /*
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+ * Map all of RAM so that we can access arguments in the 1:1
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+ * mapping when making EFI runtime calls.
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+ */
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+ for_each_efi_memory_desc(&memmap, md) {
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+ if (md->type != EFI_CONVENTIONAL_MEMORY &&
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+ md->type != EFI_LOADER_DATA &&
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+ md->type != EFI_LOADER_CODE)
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+ continue;
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+
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+ pfn = md->phys_addr >> PAGE_SHIFT;
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+ npages = md->num_pages;
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+
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+ if (kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, npages, 0)) {
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+ pr_err("Failed to map 1:1 memory\n");
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+ return 1;
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+ }
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+ }
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+
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page = alloc_page(GFP_KERNEL|__GFP_DMA32);
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if (!page)
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panic("Unable to allocate EFI runtime stack < 4GB\n");
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