https://github.com/torvalds/linux
Revision 745c51673e289acf4d9ffc2835524de73ef923fd authored by Matt Fleming on 07 June 2014, 11:26:20 UTC, committed by H. Peter Anvin on 07 June 2014, 16:31:00 UTC
commit 7d453eee36ae ("x86/efi: Wire up CONFIG_EFI_MIXED") introduced a regression for the functionality to load kernels above 4G. The relevant (incorrect) reasoning behind this change can be seen in the commit message, "The xloadflags field in the bzImage header is also updated to reflect that the kernel supports both entry points by setting both of XLF_EFI_HANDOVER_32 and XLF_EFI_HANDOVER_64 when CONFIG_EFI_MIXED=y. XLF_CAN_BE_LOADED_ABOVE_4G is disabled so that the kernel text is guaranteed to be addressable with 32-bits." This is obviously bogus since 32-bit EFI loaders will never place the kernel above the 4G mark. So this restriction is entirely unnecessary. But things are worse than that - since we want to encourage people to always compile with CONFIG_EFI_MIXED=y so that their kernels work out of the box for both 32-bit and 64-bit firmware, commit 7d453eee36ae effectively disables XLF_CAN_BE_LOADED_ABOVE_4G completely. Remove the overzealous and superfluous restriction and restore the XLF_CAN_BE_LOADED_ABOVE_4G functionality. Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Link: http://lkml.kernel.org/r/1402140380-15377-1-git-send-email-matt@console-pimps.org Signed-off-by: H. Peter Anvin <hpa@zytor.com>
1 parent 1778754
Tip revision: 745c51673e289acf4d9ffc2835524de73ef923fd authored by Matt Fleming on 07 June 2014, 11:26:20 UTC
x86/boot: EFI_MIXED should not prohibit loading above 4G
x86/boot: EFI_MIXED should not prohibit loading above 4G
Tip revision: 745c516
kdb_hello.c
/*
* Created by: Jason Wessel <jason.wessel@windriver.com>
*
* Copyright (c) 2010 Wind River Systems, Inc. All Rights Reserved.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/module.h>
#include <linux/kdb.h>
/*
* All kdb shell command call backs receive argc and argv, where
* argv[0] is the command the end user typed
*/
static int kdb_hello_cmd(int argc, const char **argv)
{
if (argc > 1)
return KDB_ARGCOUNT;
if (argc)
kdb_printf("Hello %s.\n", argv[1]);
else
kdb_printf("Hello world!\n");
return 0;
}
static int __init kdb_hello_cmd_init(void)
{
/*
* Registration of a dynamically added kdb command is done with
* kdb_register() with the arguments being:
* 1: The name of the shell command
* 2: The function that processes the command
* 3: Description of the usage of any arguments
* 4: Descriptive text when you run help
* 5: Number of characters to complete the command
* 0 == type the whole command
* 1 == match both "g" and "go" for example
*/
kdb_register("hello", kdb_hello_cmd, "[string]",
"Say Hello World or Hello [string]", 0);
return 0;
}
static void __exit kdb_hello_cmd_exit(void)
{
kdb_unregister("hello");
}
module_init(kdb_hello_cmd_init);
module_exit(kdb_hello_cmd_exit);
MODULE_AUTHOR("WindRiver");
MODULE_DESCRIPTION("KDB example to add a hello command");
MODULE_LICENSE("GPL");
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