Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 22def768 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: make fixmap region addressing grow with index 



It's much easier to reason about alignment and coloring of regions
located in the fixmap when fixmap index is just a PFN within the fixmap
region. Change fixmap addressing so that index 0 corresponds to
FIXADDR_START instead of the FIXADDR_TOP.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent 52247123

arch/xtensa/include/asm/fixmap.h

+24 −3
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ 
 * addresses. The point is to have a constant address at

 * compile time, but to set the physical address only

 * in the boot process. We allocate these special addresses

 * from the end of the consistent memory region backwards.

 * from the start of the consistent memory region upwards.

 * Also this lets us do fail-safe vmalloc(), we

 * can guarantee that these special addresses and

 * vmalloc()-ed addresses never overlap.
@@ -47,7 +47,28 @@ enum fixed_addresses { 
#define FIXADDR_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)

#define FIXADDR_START	((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK)



#include <asm-generic/fixmap.h>

#define __fix_to_virt(x)	(FIXADDR_START + ((x) << PAGE_SHIFT))

#define __virt_to_fix(x)	(((x) - FIXADDR_START) >> PAGE_SHIFT)



#ifndef __ASSEMBLY__

/*

 * 'index to address' translation. If anyone tries to use the idx

 * directly without translation, we catch the bug with a NULL-deference

 * kernel oops. Illegal ranges of incoming indices are caught too.

 */

static __always_inline unsigned long fix_to_virt(const unsigned int idx)

{

	BUILD_BUG_ON(idx >= __end_of_fixed_addresses);

	return __fix_to_virt(idx);

}



static inline unsigned long virt_to_fix(const unsigned long vaddr)

{

	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);

	return __virt_to_fix(vaddr);

}



#endif



#define kmap_get_fixmap_pte(vaddr) \

	pte_offset_kernel( \

arch/xtensa/mm/highmem.c

+3 −3
Original line number Diff line number Diff line
@@ -28,9 +28,9 @@ void *kmap_atomic(struct page *page) 
	idx = type + KM_TYPE_NR * smp_processor_id();

	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);

#ifdef CONFIG_DEBUG_HIGHMEM

	BUG_ON(!pte_none(*(kmap_pte - idx)));

	BUG_ON(!pte_none(*(kmap_pte + idx)));

#endif

	set_pte(kmap_pte - idx, mk_pte(page, PAGE_KERNEL_EXEC));

	set_pte(kmap_pte + idx, mk_pte(page, PAGE_KERNEL_EXEC));



	return (void *)vaddr;

}
@@ -51,7 +51,7 @@ void __kunmap_atomic(void *kvaddr) 
		 * is a bad idea also, in case the page changes cacheability

		 * attributes or becomes a protected page in a hypervisor.

		 */

		pte_clear(&init_mm, kvaddr, kmap_pte - idx);

		pte_clear(&init_mm, kvaddr, kmap_pte + idx);

		local_flush_tlb_kernel_range((unsigned long)kvaddr,

					     (unsigned long)kvaddr + PAGE_SIZE);