forked from mirrors/linux
cf40361ede
Commiteeb89e2bb1("x86/efi: Load fixmap GDT in efi_call_phys_epilog()") moved loading the fixmap in efi_call_phys_epilog() after load_cr3() since it was assumed to be more logical. Turns out this is incorrect: In efi_call_phys_prolog(), the gdt with its physical address is loaded first, and when the %cr3 is reloaded in _epilog from initial_page_table to swapper_pg_dir again the gdt is no longer mapped. This results in a triple fault if an interrupt occurs after load_cr3() and before load_fixmap_gdt(0). Calling load_fixmap_gdt(0) first restores the execution order prior to commiteeb89e2bb1and fixes the problem. Fixes:eeb89e2bb1("x86/efi: Load fixmap GDT in efi_call_phys_epilog()") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: linux-efi@vger.kernel.org Cc: Andy Lutomirski <luto@amacapital.net> Cc: Joerg Roedel <jroedel@suse.de> Link: https://lkml.kernel.org/r/1536689892-21538-1-git-send-email-linux@roeck-us.net
97 lines
2.3 KiB
C
97 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Extensible Firmware Interface
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*
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* Based on Extensible Firmware Interface Specification version 1.0
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*
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* Copyright (C) 1999 VA Linux Systems
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* Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
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* Copyright (C) 1999-2002 Hewlett-Packard Co.
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* David Mosberger-Tang <davidm@hpl.hp.com>
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* Stephane Eranian <eranian@hpl.hp.com>
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*
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* All EFI Runtime Services are not implemented yet as EFI only
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* supports physical mode addressing on SoftSDV. This is to be fixed
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* in a future version. --drummond 1999-07-20
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*
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* Implemented EFI runtime services and virtual mode calls. --davidm
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*
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* Goutham Rao: <goutham.rao@intel.com>
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* Skip non-WB memory and ignore empty memory ranges.
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/ioport.h>
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#include <linux/efi.h>
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#include <asm/io.h>
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#include <asm/desc.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/efi.h>
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/*
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* To make EFI call EFI runtime service in physical addressing mode we need
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* prolog/epilog before/after the invocation to claim the EFI runtime service
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* handler exclusively and to duplicate a memory mapping in low memory space,
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* say 0 - 3G.
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*/
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int __init efi_alloc_page_tables(void)
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{
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return 0;
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}
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void efi_sync_low_kernel_mappings(void) {}
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void __init efi_dump_pagetable(void)
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{
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#ifdef CONFIG_EFI_PGT_DUMP
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ptdump_walk_pgd_level(NULL, swapper_pg_dir);
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#endif
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}
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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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return 0;
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}
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void __init efi_map_region(efi_memory_desc_t *md)
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{
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old_map_region(md);
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}
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void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
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void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
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pgd_t * __init efi_call_phys_prolog(void)
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{
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struct desc_ptr gdt_descr;
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pgd_t *save_pgd;
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/* Current pgd is swapper_pg_dir, we'll restore it later: */
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save_pgd = swapper_pg_dir;
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load_cr3(initial_page_table);
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__flush_tlb_all();
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gdt_descr.address = get_cpu_gdt_paddr(0);
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gdt_descr.size = GDT_SIZE - 1;
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load_gdt(&gdt_descr);
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return save_pgd;
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}
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void __init efi_call_phys_epilog(pgd_t *save_pgd)
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{
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load_fixmap_gdt(0);
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load_cr3(save_pgd);
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__flush_tlb_all();
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}
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void __init efi_runtime_update_mappings(void)
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{
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if (__supported_pte_mask & _PAGE_NX)
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runtime_code_page_mkexec();
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}
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