diff options
Diffstat (limited to 'arch/x86/platform/efi/efi_32.c')
| -rw-r--r-- | arch/x86/platform/efi/efi_32.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c new file mode 100644 index 000000000000..5cab48ee61a4 --- /dev/null +++ b/arch/x86/platform/efi/efi_32.c @@ -0,0 +1,112 @@ +/* + * Extensible Firmware Interface + * + * Based on Extensible Firmware Interface Specification version 1.0 + * + * Copyright (C) 1999 VA Linux Systems + * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> + * Copyright (C) 1999-2002 Hewlett-Packard Co. + * David Mosberger-Tang <davidm@hpl.hp.com> + * Stephane Eranian <eranian@hpl.hp.com> + * + * All EFI Runtime Services are not implemented yet as EFI only + * supports physical mode addressing on SoftSDV. This is to be fixed + * in a future version. --drummond 1999-07-20 + * + * Implemented EFI runtime services and virtual mode calls. --davidm + * + * Goutham Rao: <goutham.rao@intel.com> + * Skip non-WB memory and ignore empty memory ranges. + */ + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/ioport.h> +#include <linux/efi.h> + +#include <asm/io.h> +#include <asm/page.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/efi.h> + +/* + * To make EFI call EFI runtime service in physical addressing mode we need + * prelog/epilog before/after the invocation to disable interrupt, to + * claim EFI runtime service handler exclusively and to duplicate a memory in + * low memory space say 0 - 3G. + */ + +static unsigned long efi_rt_eflags; +static pgd_t efi_bak_pg_dir_pointer[2]; + +void efi_call_phys_prelog(void) +{ + unsigned long cr4; + unsigned long temp; + struct desc_ptr gdt_descr; + + local_irq_save(efi_rt_eflags); + + /* + * If I don't have PAE, I should just duplicate two entries in page + * directory. If I have PAE, I just need to duplicate one entry in + * page directory. + */ + cr4 = read_cr4_safe(); + + if (cr4 & X86_CR4_PAE) { + efi_bak_pg_dir_pointer[0].pgd = + swapper_pg_dir[pgd_index(0)].pgd; + swapper_pg_dir[0].pgd = + swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd; + } else { + efi_bak_pg_dir_pointer[0].pgd = + swapper_pg_dir[pgd_index(0)].pgd; + efi_bak_pg_dir_pointer[1].pgd = + swapper_pg_dir[pgd_index(0x400000)].pgd; + swapper_pg_dir[pgd_index(0)].pgd = + swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd; + temp = PAGE_OFFSET + 0x400000; + swapper_pg_dir[pgd_index(0x400000)].pgd = + swapper_pg_dir[pgd_index(temp)].pgd; + } + + /* + * After the lock is released, the original page table is restored. + */ + __flush_tlb_all(); + + gdt_descr.address = __pa(get_cpu_gdt_table(0)); + gdt_descr.size = GDT_SIZE - 1; + load_gdt(&gdt_descr); +} + +void efi_call_phys_epilog(void) +{ + unsigned long cr4; + struct desc_ptr gdt_descr; + + gdt_descr.address = (unsigned long)get_cpu_gdt_table(0); + gdt_descr.size = GDT_SIZE - 1; + load_gdt(&gdt_descr); + + cr4 = read_cr4_safe(); + + if (cr4 & X86_CR4_PAE) { + swapper_pg_dir[pgd_index(0)].pgd = + efi_bak_pg_dir_pointer[0].pgd; + } else { + swapper_pg_dir[pgd_index(0)].pgd = + efi_bak_pg_dir_pointer[0].pgd; + swapper_pg_dir[pgd_index(0x400000)].pgd = + efi_bak_pg_dir_pointer[1].pgd; + } + + /* + * After the lock is released, the original page table is restored. + */ + __flush_tlb_all(); + + local_irq_restore(efi_rt_eflags); +} |