From: Matt Porter <mporter@kernel.crashing.org>
This makes the PPC40x lowmem large tlb mapping selectable via a cmdline
option. This allows use of the normal page-sized mapping so that kernel
text can be read only if desired.
Signed-off-by: Josh Boyer <jwboyer@charter.net>
Signed-off-by: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/ppc/mm/4xx_mmu.c | 5 +++++
25-akpm/arch/ppc/mm/init.c | 5 +++++
2 files changed, 10 insertions(+)
diff -puN arch/ppc/mm/4xx_mmu.c~ppc32-make-ppc40x-large-tlb-mapping-optional arch/ppc/mm/4xx_mmu.c
--- 25/arch/ppc/mm/4xx_mmu.c~ppc32-make-ppc40x-large-tlb-mapping-optional 2004-08-15 14:23:54.512737360 -0700
+++ 25-akpm/arch/ppc/mm/4xx_mmu.c 2004-08-15 14:23:54.517736600 -0700
@@ -52,6 +52,7 @@
#include <asm/setup.h>
#include "mmu_decl.h"
+extern int __map_without_ltlbs;
/*
* MMU_init_hw does the chip-specific initialization of the MMU hardware.
*/
@@ -102,6 +103,10 @@ unsigned long __init mmu_mapin_ram(void)
p = PPC_MEMSTART;
s = 0;
+ if (__map_without_ltlbs) {
+ return s;
+ }
+
while (s <= (total_lowmem - LARGE_PAGE_SIZE_16M)) {
pmd_t *pmdp;
unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC | _PAGE_HWWRITE;
diff -puN arch/ppc/mm/init.c~ppc32-make-ppc40x-large-tlb-mapping-optional arch/ppc/mm/init.c
--- 25/arch/ppc/mm/init.c~ppc32-make-ppc40x-large-tlb-mapping-optional 2004-08-15 14:23:54.513737208 -0700
+++ 25-akpm/arch/ppc/mm/init.c 2004-08-15 14:23:54.517736600 -0700
@@ -104,6 +104,7 @@ extern unsigned long sysmap_size;
* -- Cort
*/
int __map_without_bats;
+int __map_without_ltlbs;
/* max amount of RAM to use */
unsigned long __max_memory;
@@ -204,6 +205,10 @@ void MMU_setup(void)
__map_without_bats = 1;
}
+ if (strstr(cmd_line, "noltlbs")) {
+ __map_without_ltlbs = 1;
+ }
+
/* Look for mem= option on command line */
if (strstr(cmd_line, "mem=")) {
char *p, *q;
_