x86, setup: ACPI 3, BIOS workaround for E820-probing code (c549e71d) · Commits · 戴 / test

arch/x86/boot/memory.c

+17 −4

Original line number	Diff line number	Diff line
		@@ -2,6 +2,7 @@
		*
		* Copyright (C) 1991, 1992 Linus Torvalds
		* Copyright 2007 rPath, Inc. - All Rights Reserved
		* Copyright 2009 Intel Corporation; author H. Peter Anvin
		*
		* This file is part of the Linux kernel, and is made available under
		* the terms of the GNU General Public License version 2.
		@@ -16,6 +17,11 @@

		#define SMAP 0x534d4150 /* ASCII "SMAP" */

		struct e820_ext_entry {
		struct e820entry std;
		u32 ext_flags;
		} __attribute__((packed));

		static int detect_memory_e820(void)
		{
		int count = 0;
		@@ -23,9 +29,10 @@ static int detect_memory_e820(void)
		u32 size, id, edi;
		u8 err;
		struct e820entry *desc = boot_params.e820_map;
		static struct e820_ext_entry buf; /* static so it is zeroed */

		do {
		size = sizeof(struct e820entry);
		size = sizeof buf;

		/* Important: %edx and %esi are clobbered by some BIOSes,
		so they must be either used for the error output
		@@ -33,8 +40,8 @@ static int detect_memory_e820(void)
		is something out there clobbering %ebp and %edi, too. */
		asm("pushl %%ebp; int $0x15; popl %%ebp; setc %0"
		: "=d" (err), "+b" (next), "=a" (id), "+c" (size),
		"=D" (edi), "=m" (*desc)
		: "D" (desc), "d" (SMAP), "a" (0xe820)
		"=D" (edi), "+m" (buf)
		: "D" (&buf), "d" (SMAP), "a" (0xe820)
		: "esi");

		/* BIOSes which terminate the chain with CF = 1 as opposed
		@@ -53,8 +60,14 @@ static int detect_memory_e820(void)
		break;
		}

		/* ACPI 3.0 added the extended flags support. If bit 0
		in the extended flags is zero, we're supposed to simply
		ignore the entry -- a backwards incompatible change! */
		if (size > 20 && !(buf.ext_flags & 1))
		continue;

		*desc++ = buf.std;
		count++;
		desc++;
		} while (next && count < ARRAY_SIZE(boot_params.e820_map));

		return boot_params.e820_entries = count;

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