+ x86-fix-handling-of-the-reservetop-boot-option.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     x86: fix handling of the 'reservetop' boot option
has been added to the -mm tree.  Its filename is
     x86-fix-handling-of-the-reservetop-boot-option.patch

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------------------------------------------------------
Subject: x86: fix handling of the 'reservetop' boot option
From: Liang Li <liang.li@windriver.com>

When specifying the 'reservetop=0xbadc0de' kernel parameter, the kernel
will stop booting due to a early_ioremap bug that relate to commit
8827247ff ("x86: don't define __this_fixmap_does_not_exist()").

The root cause of boot failure problem is the value of 'slot_virt[i]' was
initialized in setup_arch->early_ioremap_init.  But later in setup_arch,
the function 'parse_early_param' will modify 'FIXADDR_TOP' when
'reservetop=0xbadc0de' being specified.

The simplest fix might be use __fix_to_virt(idx0) to get updated value
of 'FIXADDR_TOP' in '__early_ioremap' instead of reference old value
from slot_virt[slot] directly.

Signed-off-by: Liang Li <liang.li@windriver.com>
Cc: Wang Chen <wangchen@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/mm/ioremap.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN arch/x86/mm/ioremap.c~x86-fix-handling-of-the-reservetop-boot-option arch/x86/mm/ioremap.c
--- a/arch/x86/mm/ioremap.c~x86-fix-handling-of-the-reservetop-boot-option
+++ a/arch/x86/mm/ioremap.c
@@ -537,9 +537,9 @@ __early_ioremap(resource_size_t phys_add
 		--nrpages;
 	}
 	if (early_ioremap_debug)
-		printk(KERN_CONT "%08lx + %08lx\n", offset, slot_virt[slot]);
+		printk(KERN_CONT "%08lx + %08lx\n", offset, __fix_to_virt(idx0));
 
-	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
+	prev_map[slot] = (void __iomem *)(offset + __fix_to_virt(idx0));
 	return prev_map[slot];
 }
 
_

Patches currently in -mm which might be from liang.li@windriver.com are

x86-fix-handling-of-the-reservetop-boot-option.patch