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Subject[patch 05/18] DEBUG_PAGEALLOC support for s390.
From: Heiko Carstens <heiko.carstens@de.ibm.com>

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/Kconfig.debug | 8 ++++++++
arch/s390/kernel/traps.c | 5 ++++-
arch/s390/mm/init.c | 27 +++++++++++++++++++++++++++
include/asm-s390/cacheflush.h | 4 ++++
4 files changed, 43 insertions(+), 1 deletion(-)
Index: quilt-2.6/arch/s390/Kconfig.debug
===================================================================
--- quilt-2.6.orig/arch/s390/Kconfig.debug
+++ quilt-2.6/arch/s390/Kconfig.debug
@@ -6,4 +6,12 @@ config TRACE_IRQFLAGS_SUPPORT

source "lib/Kconfig.debug"

+config DEBUG_PAGEALLOC
+ bool "Debug page memory allocations"
+ depends on DEBUG_KERNEL
+ help
+ Unmap pages from the kernel linear mapping after free_pages().
+ This results in a slowdown, but helps to find certain types of
+ memory corruptions.
+
endmenu
Index: quilt-2.6/arch/s390/kernel/traps.c
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/traps.c
+++ quilt-2.6/arch/s390/kernel/traps.c
@@ -271,7 +271,10 @@ void die(const char * str, struct pt_reg
printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
- printk("SMP");
+ printk("SMP ");
+#endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ printk("DEBUG_PAGEALLOC");
#endif
printk("\n");
notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);
Index: quilt-2.6/arch/s390/mm/init.c
===================================================================
--- quilt-2.6.orig/arch/s390/mm/init.c
+++ quilt-2.6/arch/s390/mm/init.c
@@ -167,6 +167,33 @@ void __init mem_init(void)
PFN_ALIGN((unsigned long)&_eshared) - 1);
}

+#ifdef CONFIG_DEBUG_PAGEALLOC
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long address;
+ int i;
+
+ for (i = 0; i < numpages; i++) {
+ address = page_to_phys(page + i);
+ pgd = pgd_offset_k(address);
+ pud = pud_offset(pgd, address);
+ pmd = pmd_offset(pud, address);
+ pte = pte_offset_kernel(pmd, address);
+ if (!enable) {
+ ptep_invalidate(address, pte);
+ continue;
+ }
+ *pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));
+ /* Flush cpu write queue. */
+ mb();
+ }
+}
+#endif
+
void free_initmem(void)
{
unsigned long addr;
Index: quilt-2.6/include/asm-s390/cacheflush.h
===================================================================
--- quilt-2.6.orig/include/asm-s390/cacheflush.h
+++ quilt-2.6/include/asm-s390/cacheflush.h
@@ -24,4 +24,8 @@
#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
memcpy(dst, src, len)

+#ifdef CONFIG_DEBUG_PAGEALLOC
+void kernel_map_pages(struct page *page, int numpages, int enable);
+#endif
+
#endif /* _S390_CACHEFLUSH_H */
--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



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