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authorMatt Fleming <matt.fleming@intel.com>2011-12-08 12:10:50 +0000
committerH. Peter Anvin <hpa@linux.intel.com>2011-12-09 16:39:11 -0800
commit6d3e32e63f1fb47b3ba104d13dfac116df7b2bbb (patch)
tree72bdee063f7495039e55f2321a54d20bc4a8a8b2 /arch/x86/platform/efi/efi_32.c
parentdc47ce90c3a822cd7c9e9339fe4d5f61dcb26b50 (diff)
x86, efi: Make efi_call_phys_{prelog,epilog} CONFIG_RELOCATABLE-aware
efi_call_phys_prelog() sets up a 1:1 mapping of the physical address range in swapper_pg_dir. Instead of replacing then restoring entries in swapper_pg_dir we should be using initial_page_table which already contains the 1:1 mapping. It's safe to blindly switch back to swapper_pg_dir in the epilog because the physical EFI routines are only called before efi_enter_virtual_mode(), e.g. before any user processes have been forked. Therefore, we don't need to track which pgd was in %cr3 when we entered the prelog. The previous code actually contained a bug because it assumed that the kernel was loaded at a physical address within the first 8MB of ram, usually at 0x100000. However, this isn't the case with a CONFIG_RELOCATABLE=y kernel which could have been loaded anywhere in the physical address space. Also delete the ancient (and bogus) comments about the page table being restored after the lock is released. There is no locking. Cc: Matthew Garrett <mjg@redhat.com> Cc: Darrent Hart <dvhart@linux.intel.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Link: http://lkml.kernel.org/r/1323346250.3894.74.camel@mfleming-mobl1.ger.corp.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/platform/efi/efi_32.c')
-rw-r--r--arch/x86/platform/efi/efi_32.c48
1 files changed, 2 insertions, 46 deletions
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index e36bf714cb77..40e446941dd7 100644
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -39,43 +39,14 @@
*/
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.
- */
+ load_cr3(initial_page_table);
__flush_tlb_all();
gdt_descr.address = __pa(get_cpu_gdt_table(0));
@@ -85,28 +56,13 @@ void efi_call_phys_prelog(void)
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.
- */
+ load_cr3(swapper_pg_dir);
__flush_tlb_all();
local_irq_restore(efi_rt_eflags);

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