mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 17:59:32 +00:00
[POWERPC] ppc405 Fix arithmatic rollover bug when memory size under 16M
mmu_mapin_ram() loops over total_lowmem to setup page tables. However, if total_lowmem is less that 16M, the subtraction rolls over and results in a number just under 4G (because total_lowmem is an unsigned value). This patch rejigs the loop from countup to countdown to eliminate the bug. Special thanks to Magnus Hjorth who wrote the original patch to fix this bug. This patch improves on his by making the loop code simpler (which also eliminates the possibility of another rollover at the high end) and also applies the change to arch/powerpc. Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
This commit is contained in:
parent
b98ac05d5e
commit
bd942ba3db
2 changed files with 16 additions and 18 deletions
|
@ -98,13 +98,12 @@ unsigned long __init mmu_mapin_ram(void)
|
|||
|
||||
v = KERNELBASE;
|
||||
p = PPC_MEMSTART;
|
||||
s = 0;
|
||||
s = total_lowmem;
|
||||
|
||||
if (__map_without_ltlbs) {
|
||||
return s;
|
||||
}
|
||||
if (__map_without_ltlbs)
|
||||
return 0;
|
||||
|
||||
while (s <= (total_lowmem - LARGE_PAGE_SIZE_16M)) {
|
||||
while (s >= LARGE_PAGE_SIZE_16M) {
|
||||
pmd_t *pmdp;
|
||||
unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC | _PAGE_HWWRITE;
|
||||
|
||||
|
@ -116,10 +115,10 @@ unsigned long __init mmu_mapin_ram(void)
|
|||
|
||||
v += LARGE_PAGE_SIZE_16M;
|
||||
p += LARGE_PAGE_SIZE_16M;
|
||||
s += LARGE_PAGE_SIZE_16M;
|
||||
s -= LARGE_PAGE_SIZE_16M;
|
||||
}
|
||||
|
||||
while (s <= (total_lowmem - LARGE_PAGE_SIZE_4M)) {
|
||||
while (s >= LARGE_PAGE_SIZE_4M) {
|
||||
pmd_t *pmdp;
|
||||
unsigned long val = p | _PMD_SIZE_4M | _PAGE_HWEXEC | _PAGE_HWWRITE;
|
||||
|
||||
|
@ -128,8 +127,8 @@ unsigned long __init mmu_mapin_ram(void)
|
|||
|
||||
v += LARGE_PAGE_SIZE_4M;
|
||||
p += LARGE_PAGE_SIZE_4M;
|
||||
s += LARGE_PAGE_SIZE_4M;
|
||||
s -= LARGE_PAGE_SIZE_4M;
|
||||
}
|
||||
|
||||
return s;
|
||||
return total_lowmem - s;
|
||||
}
|
||||
|
|
|
@ -99,13 +99,12 @@ unsigned long __init mmu_mapin_ram(void)
|
|||
|
||||
v = KERNELBASE;
|
||||
p = PPC_MEMSTART;
|
||||
s = 0;
|
||||
s = total_lowmem;
|
||||
|
||||
if (__map_without_ltlbs) {
|
||||
return s;
|
||||
}
|
||||
if (__map_without_ltlbs)
|
||||
return 0;
|
||||
|
||||
while (s <= (total_lowmem - LARGE_PAGE_SIZE_16M)) {
|
||||
while (s >= LARGE_PAGE_SIZE_16M) {
|
||||
pmd_t *pmdp;
|
||||
unsigned long val = p | _PMD_SIZE_16M | _PAGE_HWEXEC | _PAGE_HWWRITE;
|
||||
|
||||
|
@ -117,10 +116,10 @@ unsigned long __init mmu_mapin_ram(void)
|
|||
|
||||
v += LARGE_PAGE_SIZE_16M;
|
||||
p += LARGE_PAGE_SIZE_16M;
|
||||
s += LARGE_PAGE_SIZE_16M;
|
||||
s -= LARGE_PAGE_SIZE_16M;
|
||||
}
|
||||
|
||||
while (s <= (total_lowmem - LARGE_PAGE_SIZE_4M)) {
|
||||
while (s >= LARGE_PAGE_SIZE_4M) {
|
||||
pmd_t *pmdp;
|
||||
unsigned long val = p | _PMD_SIZE_4M | _PAGE_HWEXEC | _PAGE_HWWRITE;
|
||||
|
||||
|
@ -129,8 +128,8 @@ unsigned long __init mmu_mapin_ram(void)
|
|||
|
||||
v += LARGE_PAGE_SIZE_4M;
|
||||
p += LARGE_PAGE_SIZE_4M;
|
||||
s += LARGE_PAGE_SIZE_4M;
|
||||
s -= LARGE_PAGE_SIZE_4M;
|
||||
}
|
||||
|
||||
return s;
|
||||
return total_lowmem - s;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue