linux-kernel - [PATCH v2] efi, x86: Add a "debug" option to the efi= cmdline

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Message-ID: <20150205104441.GC23980@pd.tnic>
Date:	Thu, 5 Feb 2015 11:44:41 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Matt Fleming <matt@...sole-pimps.org>
Cc:	Dave Young <dyoung@...hat.com>,
	Jon Masters <jonathan@...masters.org>,
	Laszlo Ersek <lersek@...hat.com>,
	linux-efi <linux-efi@...r.kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Matt Fleming <matt.fleming@...el.com>,
	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
	lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] efi, x86: Add a "debug" option to the efi= cmdline

From: Borislav Petkov <bp@...e.de>
Subject: [PATCH v2] efi, x86: Add a "debug" option to the efi= cmdline

... and hide the memory regions dump behind it. Make it default-off.

Signed-off-by: Borislav Petkov <bp@...e.de>
Link: http://lkml.kernel.org/r/20141209095843.GA3990@pd.tnic
Acked-by: Laszlo Ersek <lersek@...hat.com>
Acked-by: Dave Young <dyoung@...hat.com>
---
 Documentation/kernel-parameters.txt | 3 ++-
 arch/x86/platform/efi/efi.c         | 5 ++++-
 include/linux/efi.h                 | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 176d4fe4f076..101ab5601c2d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1024,7 +1024,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Format: {"off" | "on" | "skip[mbr]"}
 
 	efi=		[EFI]
-			Format: { "old_map", "nochunk", "noruntime" }
+			Format: { "old_map", "nochunk", "noruntime", "debug" }
 			old_map [X86-64]: switch to the old ioremap-based EFI
 			runtime services mapping. 32-bit still uses this one by
 			default.
@@ -1032,6 +1032,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			boot stub, as chunking can cause problems with some
 			firmware implementations.
 			noruntime : disable EFI runtime services support
+			debug: enable misc debug output
 
 	efi_no_storage_paranoia [EFI; X86]
 			Using this parameter you can use more than 50% of
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index dbc8627a5cdf..e859d56ce9f8 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -491,7 +491,8 @@ void __init efi_init(void)
 	if (efi_memmap_init())
 		return;
 
-	print_efi_memmap();
+	if (efi_enabled(EFI_DBG))
+		print_efi_memmap();
 }
 
 void __init efi_late_init(void)
@@ -939,6 +940,8 @@ static int __init arch_parse_efi_cmdline(char *str)
 {
 	if (parse_option_str(str, "old_map"))
 		set_bit(EFI_OLD_MEMMAP, &efi.flags);
+	if (parse_option_str(str, "debug"))
+		set_bit(EFI_DBG, &efi.flags);
 
 	return 0;
 }
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 0238d612750e..14cec75d7e74 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -940,6 +940,7 @@ extern int __init efi_setup_pcdp_console(char *);
 #define EFI_64BIT		5	/* Is the firmware 64-bit? */
 #define EFI_PARAVIRT		6	/* Access is via a paravirt interface */
 #define EFI_ARCH_1		7	/* First arch-specific bit */
+#define EFI_DBG			8	/* Print additional debug info at runtime */
 
 #ifdef CONFIG_EFI
 /*
-- 
2.2.0.33.gc18b867

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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