lkml.org 
[lkml]   [2007]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] Text Edit Lock - x86_64 Use kernel_tex_is_ro
Text Edit Lock - x86_64 Use kernel_tex_is_ro

It makes more sense to use the kernel_text_is_ro variable instead of
duplicating it.

And since we do not plan to call kernel_text_mark_rw()/kernel_text_unmark()
in the middle of mark_rodata_ro (we are still at boot time), there is no
need to wait until after global_flush_tlb() mark the rodata.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Andi Kleen <andi@firstfloor.org>
CC: Christoph Hellwig <hch@infradead.org>
---
arch/x86_64/mm/init.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
Index: linux-2.6-lttng/arch/x86_64/mm/init.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86_64/mm/init.c 2007-07-14 16:10:21.000000000 -0400
+++ linux-2.6-lttng/arch/x86_64/mm/init.c 2007-07-14 16:11:47.000000000 -0400
@@ -56,10 +56,6 @@ static unsigned long dma_reserve __initd

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

-#ifdef CONFIG_DEBUG_RODATA
-static int rodata_marked;
-#endif
-
/*
* NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
* physical space so we can cache the place of the first one and move
@@ -605,13 +601,12 @@ void mark_rodata_ro(void)
unsigned long start = PFN_ALIGN(_stext);
unsigned long end = PFN_ALIGN(__end_rodata);

- kernel_text_is_ro = 1;
-
change_page_attr_addr(start, (end - start) >> PAGE_SHIFT,
PAGE_KERNEL_RO);

printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
+ kernel_text_is_ro = 1;

/*
* change_page_attr_addr() requires a global_flush_tlb() call after it.
@@ -620,7 +615,6 @@ void mark_rodata_ro(void)
* of who is the culprit.
*/
global_flush_tlb();
- rodata_marked = 1;
}

/*
@@ -628,7 +622,7 @@ void mark_rodata_ro(void)
*/
void kernel_text_mark_rw(unsigned long address, size_t len)
{
- if (rodata_marked && address >= PFN_ALIGN(_text)
+ if (kernel_text_is_ro && address >= PFN_ALIGN(_text)
&& (address + len) <= PFN_ALIGN(_etext)) {
unsigned long nr_pages;
nr_pages = ((address + len) >> PAGE_SHIFT)
@@ -644,7 +638,7 @@ EXPORT_SYMBOL_GPL(kernel_text_mark_rw);

void kernel_text_unmark(unsigned long address, size_t len)
{
- if (rodata_marked && address >= PFN_ALIGN(_text)
+ if (kernel_text_is_ro && address >= PFN_ALIGN(_text)
&& (address + len) <= PFN_ALIGN(_etext)) {
unsigned long nr_pages;
nr_pages = ((address + len) >> PAGE_SHIFT)
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-07-14 22:25    [from the cache]
©2003-2011 Jasper Spaans