x86/efi: Dump the EFI page table
This is very useful for debugging issues with the recently added
pagetable switching code for EFI virtual mode.
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>
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 321a52c..61bd2ad 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -81,6 +81,15 @@
kernel.
If in doubt, say "N"
+config EFI_PGT_DUMP
+ bool "Dump the EFI pagetable"
+ depends on EFI && X86_PTDUMP
+ ---help---
+ Enable this if you want to dump the EFI page table before
+ enabling virtual mode. This can be used to debug miscellaneous
+ issues with the mapping of the EFI runtime regions into that
+ table.
+
config DEBUG_RODATA
bool "Write protect kernel read-only data structures"
default y
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index a7a8bd8..4afd3b3 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -133,6 +133,7 @@
extern void __init old_map_region(efi_memory_desc_t *md);
extern void __init runtime_code_page_mkexec(void);
extern void __init efi_runtime_mkexec(void);
+extern void __init efi_dump_pagetable(void);
struct efi_setup_data {
u64 fw_vendor;
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 876dc5b..37f20d7 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -1021,6 +1021,7 @@
efi_setup_page_tables();
efi_sync_low_kernel_mappings();
+ efi_dump_pagetable();
if (!efi_setup) {
status = phys_efi_set_virtual_address_map(
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index 0b74cdf..39496ae 100644
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -41,6 +41,7 @@
void efi_sync_low_kernel_mappings(void) {}
void efi_setup_page_tables(void) {}
+void __init efi_dump_pagetable(void) {}
void __init efi_map_region(efi_memory_desc_t *md)
{
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 0c2a234..e05c69b 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -242,3 +242,12 @@
if (__supported_pte_mask & _PAGE_NX)
runtime_code_page_mkexec();
}
+
+void __init efi_dump_pagetable(void)
+{
+#ifdef CONFIG_EFI_PGT_DUMP
+ pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
+
+ ptdump_walk_pgd_level(NULL, pgd);
+#endif
+}