Commit 88df6e90 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Paul Mackerras
Browse files

[POWERPC] DEBUG_PAGEALLOC for 32-bit 



Here's an implementation of DEBUG_PAGEALLOC for ppc32. It disables BAT
mapping and is only tested with Hash table based processor though it
shouldn't be too hard to adapt it to others.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>

 arch/powerpc/Kconfig.debug       |    9 ++++++
 arch/powerpc/mm/init_32.c        |    4 +++
 arch/powerpc/mm/pgtable_32.c     |   52 +++++++++++++++++++++++++++++++++++++++
 arch/powerpc/mm/ppc_mmu_32.c     |    4 ++-
 include/asm-powerpc/cacheflush.h |    6 ++++
 5 files changed, 74 insertions(+), 1 deletion(-)
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent ee4f2ea4

arch/powerpc/Kconfig.debug

+9 −0
Original line number Diff line number Diff line
@@ -18,6 +18,15 @@ config DEBUG_STACK_USAGE 


	  This option will slow down process creation somewhat.



config DEBUG_PAGEALLOC

        bool "Debug page memory allocations"

        depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND && PPC32

        help

          Unmap pages from the kernel linear mapping after free_pages().

          This results in a large slowdown, but helps to find certain types

          of memory corruptions.





config HCALL_STATS

	bool "Hypervisor call instrumentation"

	depends on PPC_PSERIES && DEBUG_FS

arch/powerpc/mm/init_32.c

+4 −0
Original line number Diff line number Diff line
@@ -115,6 +115,10 @@ void MMU_setup(void) 
	if (strstr(cmd_line, "noltlbs")) {

		__map_without_ltlbs = 1;

	}

#ifdef CONFIG_DEBUG_PAGEALLOC

	__map_without_bats = 1;

	__map_without_ltlbs = 1;

#endif

}



/*

arch/powerpc/mm/pgtable_32.c

+52 −0
Original line number Diff line number Diff line
@@ -451,3 +451,55 @@ exit: 
	return ret;

}



#ifdef CONFIG_DEBUG_PAGEALLOC



static int __change_page_attr(struct page *page, pgprot_t prot)

{

	pte_t *kpte;

	pmd_t *kpmd;

	unsigned long address;



	BUG_ON(PageHighMem(page));

	address = (unsigned long)page_address(page);



	if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))

		return 0;

	if (!get_pteptr(&init_mm, address, &kpte, &kpmd))

		return -EINVAL;

	set_pte_at(&init_mm, address, kpte, mk_pte(page, prot));

	wmb();

	flush_HPTE(0, address, pmd_val(*kpmd));

	pte_unmap(kpte);



	return 0;

}



/*

 * Change the page attributes of an page in the linear mapping.

 *

 * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY

 */

static int change_page_attr(struct page *page, int numpages, pgprot_t prot)

{

	int i, err = 0;

	unsigned long flags;



	local_irq_save(flags);

	for (i = 0; i < numpages; i++, page++) {

		err = __change_page_attr(page, prot);

		if (err)

			break;

	}

	local_irq_restore(flags);

	return err;

}





void kernel_map_pages(struct page *page, int numpages, int enable)

{

	if (PageHighMem(page))

		return;



	change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));

}

#endif /* CONFIG_DEBUG_PAGEALLOC */

arch/powerpc/mm/ppc_mmu_32.c

+3 −1
Original line number Diff line number Diff line
@@ -85,8 +85,10 @@ unsigned long __init mmu_mapin_ram(void) 
	unsigned long max_size = (256<<20);

	unsigned long align;



	if (__map_without_bats)

	if (__map_without_bats) {

		printk(KERN_DEBUG "RAM mapped without BATs\n");

		return 0;

	}



	/* Set up BAT2 and if necessary BAT3 to cover RAM. */

include/asm-powerpc/cacheflush.h

+6 −0
Original line number Diff line number Diff line
@@ -64,6 +64,12 @@ extern void flush_dcache_phys_range(unsigned long start, unsigned long stop); 
	memcpy(dst, src, len)







#ifdef CONFIG_DEBUG_PAGEALLOC

/* internal debugging function */

void kernel_map_pages(struct page *page, int numpages, int enable);

#endif



#endif /* __KERNEL__ */



#endif /* _ASM_POWERPC_CACHEFLUSH_H */

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