linux/arch/x86/platform/efi/efi_32.c
Borislav Petkov b7b898ae0c x86/efi: Make efi virtual runtime map passing more robust
Currently, running SetVirtualAddressMap() and passing the physical
address of the virtual map array was working only by a lucky coincidence
because the memory was present in the EFI page table too. Until Toshi
went and booted this on a big HP box - the krealloc() manner of resizing
the memmap we're doing did allocate from such physical addresses which
were not mapped anymore and boom:

http://lkml.kernel.org/r/1386806463.1791.295.camel@misato.fc.hp.com

One way to take care of that issue is to reimplement the krealloc thing
but with pages. We start with contiguous pages of order 1, i.e. 2 pages,
and when we deplete that memory (shouldn't happen all that often but you
know firmware) we realloc the next power-of-two pages.

Having the pages, it is much more handy and easy to map them into the
EFI page table with the already existing mapping code which we're using
for building the virtual mappings.

Thanks to Toshi Kani and Matt for the great debugging help.

Reported-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2014-03-04 16:17:18 +00:00

91 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
* 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;
void efi_sync_low_kernel_mappings(void) {}
void __init efi_dump_pagetable(void) {}
int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
return 0;
}
void 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) {}
void efi_call_phys_prelog(void)
{
struct desc_ptr gdt_descr;
local_irq_save(efi_rt_eflags);
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);
}
void efi_call_phys_epilog(void)
{
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(swapper_pg_dir);
__flush_tlb_all();
local_irq_restore(efi_rt_eflags);
}
void __init efi_runtime_mkexec(void)
{
if (__supported_pte_mask & _PAGE_NX)
runtime_code_page_mkexec();
}