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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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185034e72d
Some firmware still needs a 1:1 (virt->phys) mapping even after we've called SetVirtualAddressMap(). So install the mapping alongside our existing kernel mapping whenever we make EFI calls in virtual mode. This bug was discovered on ASUS machines where the firmware implementation of GetTime() accesses the RTC device via physical addresses, even though that's bogus per the UEFI spec since we've informed the firmware via SetVirtualAddressMap() that the boottime memory map is no longer valid. This bug seems to be present in a lot of consumer devices, so there's not a lot we can do about this spec violation apart from workaround it. Cc: JérômeCarretero <cJ-ko@zougloub.eu> Cc: Vasco Dias <rafa.vasco@gmail.com> Acked-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
/*
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* x86_64 specific EFI support functions
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* Based on Extensible Firmware Interface Specification version 1.0
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*
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* Copyright (C) 2005-2008 Intel Co.
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* Fenghua Yu <fenghua.yu@intel.com>
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* Bibo Mao <bibo.mao@intel.com>
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* Chandramouli Narayanan <mouli@linux.intel.com>
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* Huang Ying <ying.huang@intel.com>
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*
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* Code to convert EFI to E820 map has been implemented in elilo bootloader
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* based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
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* is setup appropriately for EFI runtime code.
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* - mouli 06/14/2007.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/bootmem.h>
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#include <linux/ioport.h>
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#include <linux/module.h>
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#include <linux/efi.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/reboot.h>
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#include <asm/setup.h>
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#include <asm/page.h>
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#include <asm/e820.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/proto.h>
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#include <asm/efi.h>
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#include <asm/cacheflush.h>
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#include <asm/fixmap.h>
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static pgd_t save_pgd __initdata;
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static unsigned long efi_flags __initdata;
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static void __init early_code_mapping_set_exec(int executable)
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{
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efi_memory_desc_t *md;
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void *p;
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if (!(__supported_pte_mask & _PAGE_NX))
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return;
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/* Make EFI service code area executable */
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for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
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md = p;
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if (md->type == EFI_RUNTIME_SERVICES_CODE ||
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md->type == EFI_BOOT_SERVICES_CODE)
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efi_set_executable(md, executable);
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}
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}
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unsigned long efi_call_virt_prelog(void)
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{
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unsigned long saved;
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saved = read_cr3();
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write_cr3(real_mode_header->trampoline_pgd);
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return saved;
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}
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void efi_call_virt_epilog(unsigned long saved)
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{
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write_cr3(saved);
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}
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void __init efi_call_phys_prelog(void)
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{
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unsigned long vaddress;
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early_code_mapping_set_exec(1);
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local_irq_save(efi_flags);
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vaddress = (unsigned long)__va(0x0UL);
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save_pgd = *pgd_offset_k(0x0UL);
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set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
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__flush_tlb_all();
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}
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void __init efi_call_phys_epilog(void)
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{
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/*
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* After the lock is released, the original page table is restored.
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*/
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set_pgd(pgd_offset_k(0x0UL), save_pgd);
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__flush_tlb_all();
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local_irq_restore(efi_flags);
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early_code_mapping_set_exec(0);
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}
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void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
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u32 type)
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{
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unsigned long last_map_pfn;
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if (type == EFI_MEMORY_MAPPED_IO)
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return ioremap(phys_addr, size);
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last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
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if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
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unsigned long top = last_map_pfn << PAGE_SHIFT;
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efi_ioremap(top, size - (top - phys_addr), type);
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}
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return (void __iomem *)__va(phys_addr);
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}
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