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ARM: 6996/1: mm: Poison freed init memory 

Poisoning __init marked memory can be useful when tracking down
obscure memory corruption bugs. Therefore, poison init memory
with 0xe7fddef0 to catch bugs earlier. The poison value is an
undefined instruction in ARM mode and branch to an undefined
instruction in Thumb mode.

Change-Id: Ibb91bee46b829b0deac9f4e592040a0054968998
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[sboyd@codeaurora.org: Fix conflicts from total_unmovable_pages]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

ARM: 7010/1: mm: fix invalid loop for poison_init_mem

poison_init_mem() used a loop of:

	while ((count = count - 4))

which has 2 problems - an off by one error so that we do one less word
than we should, and the other is that if count == 0 then we loop forever
and poison too much.  On a platform with HAVE_TCM=y but nothing in the
TCM's, this caused corruption and the platform failed to boot.

Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This commit is contained in:
Stephen Boyd 2011-07-07 18:43:36 +01:00
parent bd2c2e3abd
commit 3ceed597e9
1 changed files with 14 additions and 0 deletions
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14
arch/arm/mm/init.c
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@ -491,6 +491,17 @@ static inline int free_area(unsigned long pfn, unsigned long end, char *s)
return pages;
}
/*
* Poison init memory with an undefined instruction (ARM) or a branch to an
* undefined instruction (Thumb).
*/
static inline void poison_init_mem(void *s, size_t count)
{
u32 *p = (u32 *)s;
for (; count != 0; count -= 4)
*p++ = 0xe7fddef0;
}
static inline void
free_memmap(unsigned long start_pfn, unsigned long end_pfn)
{
@ -799,12 +810,14 @@ void free_initmem(void)
#ifdef CONFIG_HAVE_TCM
extern char __tcm_start, __tcm_end;
poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
totalram_pages += free_area(__phys_to_pfn(__pa(&__tcm_start)),
__phys_to_pfn(__pa(&__tcm_end)),
"TCM link");
#endif
if (!machine_is_integrator() && !machine_is_cintegrator()) {
poison_init_mem(__init_begin, __init_end - __init_begin);
reclaimed_initmem = free_area(__phys_to_pfn(__pa(__init_begin)),
__phys_to_pfn(__pa(__init_end)),
"init");
@ -850,6 +863,7 @@ void free_initrd_mem(unsigned long start, unsigned long end)
{
unsigned long reclaimed_initrd_mem;
if (!keep_initrd) {
poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
reclaimed_initrd_mem = free_area(__phys_to_pfn(__pa(start)),
__phys_to_pfn(__pa(end)),
"initrd");