[tip:x86/mm] x86, ACPI, mm: Kill max_low_pfn_mapped

From: tip-bot for Yinghai Lu
Date: Fri Jun 14 2013 - 17:31:44 EST


Commit-ID: b19feb388cdee35bf991e4977d1936f6d23c75a8
Gitweb: http://git.kernel.org/tip/b19feb388cdee35bf991e4977d1936f6d23c75a8
Author: Yinghai Lu <yinghai@xxxxxxxxxx>
AuthorDate: Thu, 13 Jun 2013 21:02:50 +0800
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Fri, 14 Jun 2013 14:03:37 -0700

x86, ACPI, mm: Kill max_low_pfn_mapped

Now we have pfn_mapped[] array, and max_low_pfn_mapped should not
be used anymore. Users should use pfn_mapped[] or just
1UL<<(32-PAGE_SHIFT) instead.

The only user of max_low_pfn_mapped is ACPI_INITRD_TABLE_OVERRIDE.
We could change to use 1U<<(32_PAGE_SHIFT) with it, aka under 4G.

Known problem:
There is another user of max_low_pfn_mapped: i915 device driver.
But the code is commented out by a pair of "#if 0 ... #endif".
Not sure why the driver developers want to do that.

-v2: Leave alone max_low_pfn_mapped in i915 code according to tj.

Suggested-by: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1371128589-8953-4-git-send-email-tangchen@xxxxxxxxxxxxxx
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: Jacob Shin <jacob.shin@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Tested-by: Thomas Renninger <trenn@xxxxxxx>
Reviewed-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Tested-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/page_types.h | 1 -
arch/x86/kernel/setup.c | 4 +---
arch/x86/mm/init.c | 4 ----
drivers/acpi/osl.c | 6 +++---
4 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
index 54c9787..b012b82 100644
--- a/arch/x86/include/asm/page_types.h
+++ b/arch/x86/include/asm/page_types.h
@@ -43,7 +43,6 @@

extern int devmem_is_allowed(unsigned long pagenr);

-extern unsigned long max_low_pfn_mapped;
extern unsigned long max_pfn_mapped;

static inline phys_addr_t get_max_mapped(void)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 66ab495..6ca5f2c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -112,13 +112,11 @@
#include <asm/prom.h>

/*
- * max_low_pfn_mapped: highest direct mapped pfn under 4GB
- * max_pfn_mapped: highest direct mapped pfn over 4GB
+ * max_pfn_mapped: highest direct mapped pfn
*
* The direct mapping only covers E820_RAM regions, so the ranges and gaps are
* represented by pfn_mapped
*/
-unsigned long max_low_pfn_mapped;
unsigned long max_pfn_mapped;

#ifdef CONFIG_DMI
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index eaac174..8554656 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -313,10 +313,6 @@ static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_X_MAX);

max_pfn_mapped = max(max_pfn_mapped, end_pfn);
-
- if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
- max_low_pfn_mapped = max(max_low_pfn_mapped,
- min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
}

bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index e721863..93e3194 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -624,9 +624,9 @@ void __init acpi_initrd_override(void *data, size_t size)
if (table_nr == 0)
return;

- acpi_tables_addr =
- memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
- all_tables_size, PAGE_SIZE);
+ /* under 4G at first, then above 4G */
+ acpi_tables_addr = memblock_find_in_range(0, (1ULL<<32) - 1,
+ all_tables_size, PAGE_SIZE);
if (!acpi_tables_addr) {
WARN_ON(1);
return;
--
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