linux_dsm_epyc7002/arch/x86/platform/efi/efi_32.c
Ingo Molnar 744937b0b1 efi: Clean up the efi_call_phys_[prolog|epilog]() save/restore interaction
Currently x86-64 efi_call_phys_prolog() saves into a global variable (save_pgd),
and efi_call_phys_epilog() restores the kernel pagetables from that global
variable.

Change this to a cleaner save/restore pattern where the saving function returns
the saved object and the restore function restores that.

Apply the same concept to the 32-bit code as well.

Plus this approach, as an added bonus, allows us to express the
!efi_enabled(EFI_OLD_MEMMAP) situation in a clean fashion as well,
via a 'NULL' return value.

Cc: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2015-04-01 12:46:22 +01:00

93 lines
2.3 KiB
C

/*
* 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/desc.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
* prolog/epilog before/after the invocation to claim the EFI runtime service
* handler exclusively and to duplicate a memory mapping in low memory space,
* say 0 - 3G.
*/
void efi_sync_low_kernel_mappings(void) {}
void __init efi_dump_pagetable(void) {}
int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
return 0;
}
void __init efi_cleanup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
}
void __init efi_map_region(efi_memory_desc_t *md)
{
old_map_region(md);
}
void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
pgd_t * __init efi_call_phys_prolog(void)
{
struct desc_ptr gdt_descr;
pgd_t *save_pgd;
/* Current pgd is swapper_pg_dir, we'll restore it later: */
save_pgd = swapper_pg_dir;
load_cr3(initial_page_table);
__flush_tlb_all();
gdt_descr.address = __pa(get_cpu_gdt_table(0));
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
return save_pgd;
}
void __init efi_call_phys_epilog(pgd_t *save_pgd)
{
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);
load_cr3(save_pgd);
__flush_tlb_all();
}
void __init efi_runtime_mkexec(void)
{
if (__supported_pte_mask & _PAGE_NX)
runtime_code_page_mkexec();
}