mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b17ed48040
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Huang Ying <ying.huang@intel.com>
113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/*
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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/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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* prelog/epilog before/after the invocation to disable interrupt, to
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* claim EFI runtime service handler exclusively and to duplicate a memory in
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* low memory space say 0 - 3G.
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*/
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static unsigned long efi_rt_eflags;
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static pgd_t efi_bak_pg_dir_pointer[2];
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void efi_call_phys_prelog(void)
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{
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unsigned long cr4;
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unsigned long temp;
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struct desc_ptr gdt_descr;
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local_irq_save(efi_rt_eflags);
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/*
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* If I don't have PAE, I should just duplicate two entries in page
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* directory. If I have PAE, I just need to duplicate one entry in
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* page directory.
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*/
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cr4 = read_cr4_safe();
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if (cr4 & X86_CR4_PAE) {
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efi_bak_pg_dir_pointer[0].pgd =
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swapper_pg_dir[pgd_index(0)].pgd;
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swapper_pg_dir[0].pgd =
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swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
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} else {
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efi_bak_pg_dir_pointer[0].pgd =
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swapper_pg_dir[pgd_index(0)].pgd;
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efi_bak_pg_dir_pointer[1].pgd =
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swapper_pg_dir[pgd_index(0x400000)].pgd;
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swapper_pg_dir[pgd_index(0)].pgd =
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swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
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temp = PAGE_OFFSET + 0x400000;
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swapper_pg_dir[pgd_index(0x400000)].pgd =
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swapper_pg_dir[pgd_index(temp)].pgd;
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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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__flush_tlb_all();
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gdt_descr.address = __pa(get_cpu_gdt_table(0));
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gdt_descr.size = GDT_SIZE - 1;
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load_gdt(&gdt_descr);
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}
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void efi_call_phys_epilog(void)
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{
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unsigned long cr4;
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struct desc_ptr gdt_descr;
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gdt_descr.address = (unsigned long)get_cpu_gdt_table(0);
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gdt_descr.size = GDT_SIZE - 1;
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load_gdt(&gdt_descr);
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cr4 = read_cr4_safe();
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if (cr4 & X86_CR4_PAE) {
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swapper_pg_dir[pgd_index(0)].pgd =
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efi_bak_pg_dir_pointer[0].pgd;
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} else {
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swapper_pg_dir[pgd_index(0)].pgd =
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efi_bak_pg_dir_pointer[0].pgd;
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swapper_pg_dir[pgd_index(0x400000)].pgd =
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efi_bak_pg_dir_pointer[1].pgd;
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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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__flush_tlb_all();
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local_irq_restore(efi_rt_eflags);
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}
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