Commit-ID: 753b11ef8e92a1c1bbe97f2a5ec14bdd1ef2e6fe
Gitweb: http://git.kernel.org/tip/753b11ef8e92a1c1bbe97f2a5ec14bdd1ef2e6fe
Author: Matt Fleming <[email protected]>
AuthorDate: Thu, 21 Jan 2016 14:11:59 +0000
Committer: Ingo Molnar <[email protected]>
CommitDate: Thu, 21 Jan 2016 21:01:34 +0100
x86/efi: Setup separate EFI page tables in kexec paths
The switch to using a new dedicated page table for EFI runtime
calls in commit commit 67a9108ed431 ("x86/efi: Build our own
page table structures") failed to take into account changes
required for the kexec code paths, which are unfortunately
duplicated in the EFI code.
Call the allocation and setup functions in
kexec_enter_virtual_mode() just like we do for
__efi_enter_virtual_mode() to avoid hitting NULL-pointer
dereferences when making EFI runtime calls.
At the very least, the call to efi_setup_page_tables() should
have existed for kexec before the following commit:
67a9108ed431 ("x86/efi: Build our own page table structures")
Things just magically worked because we were actually using
the kernel's page tables that contained the required mappings.
Reported-by: Srikar Dronamraju <[email protected]>
Tested-by: Srikar Dronamraju <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Young <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Raghavendra K T <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/platform/efi/efi.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 3c1f3cd..bdd9477 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -815,6 +815,7 @@ static void __init kexec_enter_virtual_mode(void)
{
#ifdef CONFIG_KEXEC_CORE
efi_memory_desc_t *md;
+ unsigned int num_pages;
void *p;
efi.systab = NULL;
@@ -829,6 +830,12 @@ static void __init kexec_enter_virtual_mode(void)
return;
}
+ if (efi_alloc_page_tables()) {
+ pr_err("Failed to allocate EFI page tables\n");
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ return;
+ }
+
/*
* Map efi regions which were passed via setup_data. The virt_addr is a
* fixed addr which was used in first kernel of a kexec boot.
@@ -843,6 +850,14 @@ static void __init kexec_enter_virtual_mode(void)
BUG_ON(!efi.systab);
+ num_pages = ALIGN(memmap.nr_map * memmap.desc_size, PAGE_SIZE);
+ num_pages >>= PAGE_SHIFT;
+
+ if (efi_setup_page_tables(memmap.phys_map, num_pages)) {
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ return;
+ }
+
efi_sync_low_kernel_mappings();
/*
