linux-kernel - [PATCH 2/4] efi: Dump the EFI page table

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Date:	Sat, 11 Jan 2014 21:49:28 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Linux EFI <linux-efi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Cc:	Borislav Petkov <bp@...e.de>,
	Matt Fleming <matt@...sole-pimps.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	"H. Peter Anvin" <hpa@...or.com>, Dave Young <dyoung@...hat.com>,
	Toshi Kani <toshi.kani@...com>
Subject: [PATCH 2/4] efi: Dump the EFI page table

From: Borislav Petkov <bp@...e.de>

This is very useful for debugging issues with the recently added
pagetable switching code for EFI virtual mode.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/platform/efi/efi.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index d62ec87a2b26..c34be4ce94c9 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -54,6 +54,7 @@
 #include <asm/rtc.h>
 
 #define EFI_DEBUG
+#undef EFI_PGT_DBG
 
 #define EFI_MIN_RESERVE 5120
 
@@ -818,6 +819,15 @@ void efi_memory_uc(u64 addr, unsigned long size)
 	set_memory_uc(addr, npages);
 }
 
+static void dump_pagetable(void)
+{
+#if defined(EFI_PGT_DBG) && defined(CONFIG_X86_PTDUMP)
+	pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
+
+	walk_pgd_level(NULL, pgd);
+#endif
+}
+
 void __init old_map_region(efi_memory_desc_t *md)
 {
 	u64 start_pfn, end_pfn, end;
@@ -1033,6 +1043,7 @@ void __init efi_enter_virtual_mode(void)
 
 	efi_setup_page_tables();
 	efi_sync_low_kernel_mappings();
+	dump_pagetable();
 
 	if (!efi_setup) {
 		status = phys_efi_set_virtual_address_map(
-- 
1.8.5.2.192.g7794a68

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