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Commit 9905e539 authored by Linux Build Service Account's avatar Linux Build Service Account Committed by Gerrit - the friendly Code Review server
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Merge "arm64: mm: allow enforcing of strict break-before-make for page tables"

parents 62a2543c 2845235d

arch/arm64/Kconfig.debug

+3 −0
Original line number Diff line number Diff line
@@ -122,6 +122,9 @@ config KERNEL_TEXT_RDONLY 


          If unsure, say N.



config ARM64_STRICT_BREAK_BEFORE_MAKE

	bool "Enforce strict break-before-make on page table updates "



source "drivers/hwtracing/coresight/Kconfig"



endmenu

arch/arm64/include/asm/pgtable.h

+29 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <asm/bug.h>

#include <asm/proc-fns.h>



#include <asm/bug.h>

#include <asm/memory.h>

#include <asm/pgtable-hwdef.h>
@@ -229,6 +230,34 @@ static inline pmd_t pmd_mkcont(pmd_t pmd) 


static inline void set_pte(pte_t *ptep, pte_t pte)

{

#ifdef CONFIG_ARM64_STRICT_BREAK_BEFORE_MAKE

	pteval_t old = pte_val(*ptep);

	pteval_t new = pte_val(pte);



	/* Only problematic if valid -> valid */

	if (!(old & new & PTE_VALID))

		goto pte_ok;



	/* Changing attributes should go via an invalid entry */

	if (WARN_ON((old & PTE_ATTRINDX_MASK) != (new & PTE_ATTRINDX_MASK)))

		goto pte_bad;



	/* Change of OA is only an issue if one mapping is writable */

	if (!(old & new & PTE_RDONLY) &&

	    WARN_ON(pte_pfn(*ptep) != pte_pfn(pte)))

		goto pte_bad;



	goto pte_ok;



pte_bad:

	*ptep = __pte(0);

	dsb(ishst);

	asm("tlbi	vmalle1is");

	dsb(ish);

	isb();

pte_ok:

#endif



	*ptep = pte;



	/*