linux-kernel - [PATCH 1/2] x86/boot: Clarify what x86_legacy_features.reserve_bios

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Message-Id: <55bd591115498440d461857a7b64f349a5d911f3.1469135598.git.luto@kernel.org>
Date:	Thu, 21 Jul 2016 14:16:51 -0700
From:	Andy Lutomirski <luto@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Cc:	Mario Limonciello <mario_limonciello@...l.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...nel.org>
Subject: [PATCH 1/2] x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does

It doesn't just control probing for the EBDA -- it controls whether we
detect and reserve the <1MB BIOS regions in general.

Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
 arch/x86/include/asm/x86_init.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index c519c052700a..66c15a01667f 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -168,8 +168,9 @@ struct x86_legacy_devices {
  * struct x86_legacy_features - legacy x86 features
  *
  * @rtc: this device has a CMOS real-time clock present
- * @reserve_bios_regions: it's safe to search for the EBDA signature in the hardware's
- * 	low RAM
+ * @reserve_bios_regions: boot code will search for the EBDA address and the
+ * 	start of the 640k - 1M BIOS region.  If false, the platform must
+ * 	ensure that its memory map correctly reserves sub-1MB regions as needed.
  * @devices: legacy x86 devices, refer to struct x86_legacy_devices
  * 	documentation for further details.
  */
-- 
2.7.4