linux-kernel - [tip:core/memblock] x86-64: Only set max_pfn_mapped to 512 MiB if we enter via head

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Date:	Thu, 14 Oct 2010 00:31:47 GMT
From:	tip-bot for Jeremy Fitzhardinge <jeremy@...p.org>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, jeremy@...p.org, hpa@...or.com,
	mingo@...hat.com, tglx@...utronix.de, hpa@...ux.intel.com,
	jeremy.fitzhardinge@...rix.com
Subject: [tip:core/memblock] x86-64: Only set max_pfn_mapped to 512 MiB if we enter via head_64.S

Commit-ID:  859ee4f57fb4e91de8439496f62eb996f4a28ca8
Gitweb:     http://git.kernel.org/tip/859ee4f57fb4e91de8439496f62eb996f4a28ca8
Author:     Jeremy Fitzhardinge <jeremy@...p.org>
AuthorDate: Wed, 13 Oct 2010 16:34:15 -0700
Committer:  H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Wed, 13 Oct 2010 17:09:59 -0700

x86-64: Only set max_pfn_mapped to 512 MiB if we enter via head_64.S

head_64.S maps up to 512 MiB, but that is not necessarity true for
other entry paths, such as Xen.

Thus, co-locate the setting of max_pfn_mapped with the code to
actually set up the page tables in head_64.S.  The 32-bit code is
already so co-located.  (The Xen code already sets max_pfn_mapped
correctly for its own use case.)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
LKML-Reference: <4CB641F7.9040103@...p.org>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
 arch/x86/kernel/head_64.S |    2 ++
 arch/x86/kernel/setup.c   |    1 -
 2 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 239046b..b75c6f4 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -141,6 +141,8 @@ ident_complete:
 	addq	%rbp, trampoline_level4_pgt + (511*8)(%rip)
 #endif
 
+	movq    $KERNEL_IMAGE_SIZE / PAGE_SIZE, max_pfn_mapped(%rip)
+
 	/* Due to ENTRY(), sometimes the empty space gets filled with
 	 * zeros. Better take a jmp than relying on empty space being
 	 * filled with 0x90 (nop)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index b11a238..c3cebfe 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -932,7 +932,6 @@ void __init setup_arch(char **cmdline_p)
 		max_low_pfn = max_pfn;
 
 	high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
-	max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;
 #endif
 
 	/*
--
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