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Commit c6a14aa9 authored by Shiraz Hashim's avatar Shiraz Hashim Committed by Gerrit - the friendly Code Review server
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arm: provision page alloc debug support 



Equip arm to support ARCH_SUPPORTS_DEBUG_PAGEALLOC and
enable it by default.

Having this support means all pages freed at buddy level
would be marked as read-only and would help catch any
scribbling over free page area. Allocated pages mapping
attributes is restored to read/write.

ARCH_SUPPORTS_DEBUG_PAGEALLOC needs FORCE_PAGES which
ensures all kernel mapping are populated with page
granularity and it would ensure page level accesses  can
be rightly configured.

Change-Id: I9b23d1fb0b9594cc148b082c104da9a773c26057
Signed-off-by: default avatarShiraz Hashim <shashim@codeaurora.org>
Signed-off-by: default avatarCharan Teja Reddy <charante@codeaurora.org>
Signed-off-by: default avatarVijayanand Jitta <vjitta@codeaurora.org>
Signed-off-by: default avatarQingqing Zhou <qqzhou@codeaurora.org>
parent 63090e27

arch/arm/Kconfig.debug

+4 −0
Original line number Diff line number Diff line
@@ -92,6 +92,10 @@ config DEBUG_USER 
	      8 - SIGSEGV faults

	     16 - SIGBUS faults



config ARCH_SUPPORTS_DEBUG_PAGEALLOC

	def_bool y

	depends on FORCE_PAGES



config FORCE_PAGES

	bool "Force lowmem to be mapped with 4K pages"

        help

arch/arm/mm/pageattr.c

+17 −1
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2014, The Linux Foundation. All rights reserved.

 * Copyright (c) 2014,2017-2018 The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and
@@ -98,3 +98,19 @@ int set_memory_x(unsigned long addr, int numpages) 
					__pgprot(0),

					__pgprot(L_PTE_XN));

}



#ifdef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC

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

{

	unsigned long addr;



	if (PageHighMem(page))

		return;



	addr = (unsigned long) page_address(page);

	if (enable)

		set_memory_rw(addr, numpages);

	else

		set_memory_ro(addr, numpages);

}

#endif