Commit c673f1a9 authored by William Lee Irwin III's avatar William Lee Irwin III Committed by Linus Torvalds

i386: divorce CONFIG_X86_PAE from CONFIG_HIGHMEM64G

PAE is useful for more than supporting more than 4GB RAM.  It supports
expanded swapspace and NX executable protections.  Some users may want NX
or expanded swapspace support without the overhead or instability of
highmem.  For these reasons, the following patch divorces CONFIG_X86_PAE
from CONFIG_HIGHMEM64G.

Cc: Mark Lord <lkml@rtr.ca>
Signed-off-by: default avatarWilliam Irwin <wli@holomorphy.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 075bcd1f
......@@ -548,6 +548,7 @@ config HIGHMEM4G
config HIGHMEM64G
bool "64GB"
depends on !M386 && !M486
select X86_PAE
help
Select this if you have a 32-bit processor and more than 4
gigabytes of physical RAM.
......@@ -577,12 +578,12 @@ choice
config VMSPLIT_3G
bool "3G/1G user/kernel split"
config VMSPLIT_3G_OPT
depends on !HIGHMEM
depends on !X86_PAE
bool "3G/1G user/kernel split (for full 1G low memory)"
config VMSPLIT_2G
bool "2G/2G user/kernel split"
config VMSPLIT_2G_OPT
depends on !HIGHMEM
depends on !X86_PAE
bool "2G/2G user/kernel split (for full 2G low memory)"
config VMSPLIT_1G
bool "1G/3G user/kernel split"
......@@ -602,10 +603,15 @@ config HIGHMEM
default y
config X86_PAE
bool
depends on HIGHMEM64G
default y
bool "PAE (Physical Address Extension) Support"
default n
depends on !HIGHMEM4G
select RESOURCES_64BIT
help
PAE is required for NX support, and furthermore enables
larger swapspace support for non-overcommit purposes. It
has the cost of more pagetable lookup overhead, and also
consumes more pagetable space per process.
# Common NUMA Features
config NUMA
......
......@@ -273,18 +273,18 @@ unsigned long __init find_max_low_pfn(void)
printk(KERN_WARNING "Warning only %ldMB will be used.\n",
MAXMEM>>20);
if (max_pfn > MAX_NONPAE_PFN)
printk(KERN_WARNING "Use a PAE enabled kernel.\n");
printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
else
printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
max_pfn = MAXMEM_PFN;
#else /* !CONFIG_HIGHMEM */
#ifndef CONFIG_X86_PAE
#ifndef CONFIG_HIGHMEM64G
if (max_pfn > MAX_NONPAE_PFN) {
max_pfn = MAX_NONPAE_PFN;
printk(KERN_WARNING "Warning only 4GB will be used.\n");
printk(KERN_WARNING "Use a PAE enabled kernel.\n");
printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
}
#endif /* !CONFIG_X86_PAE */
#endif /* !CONFIG_HIGHMEM64G */
#endif /* !CONFIG_HIGHMEM */
} else {
if (highmem_pages == -1)
......
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