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Commit 99b4ac9a authored by Kees Cook's avatar Kees Cook
Browse files

arm: fixmap: implement __set_fixmap() 



This is used from set_fixmap() and clear_fixmap() via asm-generic/fixmap.h.
Also makes sure that the fixmap allocation fits into the expected range.

Based on patch by Rabin Vincent.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Rabin Vincent <rabin@rab.in>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
parent 836a2418

arch/arm/include/asm/fixmap.h

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ enum fixed_addresses { 
	__end_of_fixed_addresses

};



void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);



#include <asm-generic/fixmap.h>



#endif

arch/arm/mm/mmu.c

+24 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <asm/cputype.h>

#include <asm/sections.h>

#include <asm/cachetype.h>

#include <asm/fixmap.h>

#include <asm/sections.h>

#include <asm/setup.h>

#include <asm/smp_plat.h>
@@ -392,6 +393,29 @@ SET_MEMORY_FN(rw, pte_set_rw) 
SET_MEMORY_FN(x, pte_set_x)

SET_MEMORY_FN(nx, pte_set_nx)



/*

 * To avoid TLB flush broadcasts, this uses local_flush_tlb_kernel_range().

 * As a result, this can only be called with preemption disabled, as under

 * stop_machine().

 */

void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)

{

	unsigned long vaddr = __fix_to_virt(idx);

	pte_t *pte = pte_offset_kernel(pmd_off_k(vaddr), vaddr);



	/* Make sure fixmap region does not exceed available allocation. */

	BUILD_BUG_ON(FIXADDR_START + (__end_of_fixed_addresses * PAGE_SIZE) >

		     FIXADDR_END);

	BUG_ON(idx >= __end_of_fixed_addresses);



	if (pgprot_val(prot))

		set_pte_at(NULL, vaddr, pte,

			pfn_pte(phys >> PAGE_SHIFT, prot));

	else

		pte_clear(NULL, vaddr, pte);

	local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);

}



/*

 * Adjust the PMD section entries according to the CPU in use.

 */