microblaze: Highmem support (2f2f371f) · Commits · EulixOS / Software / Kernel

arch/microblaze/Kconfig

+11 −13

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		@@ -159,20 +159,18 @@ config XILINX_UNCACHED_SHADOW
		The feature requires the design to define the RAM memory controller
		window to be twice as large as the actual physical memory.

		config HIGHMEM_START_BOOL
		bool "Set high memory pool address"
		depends on ADVANCED_OPTIONS && HIGHMEM
		help
		This option allows you to set the base address of the kernel virtual
		area used to map high memory pages. This can be useful in
		optimizing the layout of kernel virtual memory.

		Say N here unless you know what you are doing.

		config HIGHMEM_START
		hex "Virtual start address of high memory pool" if HIGHMEM_START_BOOL
		config HIGHMEM
		bool "High memory support"
		depends on MMU
		default "0xfe000000"
		help
		The address space of Microblaze processors is only 4 Gigabytes large
		and it has to accommodate user address space, kernel address
		space as well as some memory mapped IO. That means that, if you
		have a large amount of physical memory and/or IO, not all of the
		memory can be "permanently mapped" by the kernel. The physical
		memory that is not permanently mapped is called "high memory".

		If unsure, say n.

		config LOWMEM_SIZE_BOOL
		bool "Set maximum low memory"

arch/microblaze/include/asm/fixmap.h

+8 −0

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		@@ -21,6 +21,10 @@
		#ifndef __ASSEMBLY__
		#include <linux/kernel.h>
		#include <asm/page.h>
		#ifdef CONFIG_HIGHMEM
		#include <linux/threads.h>
		#include <asm/kmap_types.h>
		#endif

		#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))

		@@ -44,6 +48,10 @@
		*/
		enum fixed_addresses {
		FIX_HOLE,
		#ifdef CONFIG_HIGHMEM
		FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
		FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * num_possible_cpus()) - 1,
		#endif
		__end_of_fixed_addresses
		};

arch/microblaze/include/asm/highmem.h

0 → 100644

+96 −0

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		/*
		* highmem.h: virtual kernel memory mappings for high memory
		*
		* Used in CONFIG_HIGHMEM systems for memory pages which
		* are not addressable by direct kernel virtual addresses.
		*
		* Copyright (C) 1999 Gerhard Wichert, Siemens AG
		* Gerhard.Wichert@pdb.siemens.de
		*
		*
		* Redesigned the x86 32-bit VM architecture to deal with
		* up to 16 Terabyte physical memory. With current x86 CPUs
		* we now support up to 64 Gigabytes physical RAM.
		*
		* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
		*/
		#ifndef _ASM_HIGHMEM_H
		#define _ASM_HIGHMEM_H

		#ifdef __KERNEL__

		#include <linux/init.h>
		#include <linux/interrupt.h>
		#include <linux/uaccess.h>
		#include <asm/fixmap.h>

		extern pte_t *kmap_pte;
		extern pgprot_t kmap_prot;
		extern pte_t *pkmap_page_table;

		/*
		* Right now we initialize only a single pte table. It can be extended
		* easily, subsequent pte tables have to be allocated in one physical
		* chunk of RAM.
		*/
		/*
		* We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
		* table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
		* and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
		* in case of 16K/64K/256K page sizes.
		*/

		#define PKMAP_ORDER PTE_SHIFT
		#define LAST_PKMAP (1 << PKMAP_ORDER)

		#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
		& PMD_MASK)

		#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
		#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
		#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))

		extern void kmap_high(struct page page);
		extern void kunmap_high(struct page *page);
		extern void kmap_atomic_prot(struct page page, pgprot_t prot);
		extern void __kunmap_atomic(void *kvaddr);

		static inline void kmap(struct page page)
		{
		might_sleep();
		if (!PageHighMem(page))
		return page_address(page);
		return kmap_high(page);
		}

		static inline void kunmap(struct page *page)
		{
		BUG_ON(in_interrupt());
		if (!PageHighMem(page))
		return;
		kunmap_high(page);
		}

		static inline void __kmap_atomic(struct page page)
		{
		return kmap_atomic_prot(page, kmap_prot);
		}

		static inline struct page kmap_atomic_to_page(void ptr)
		{
		unsigned long idx, vaddr = (unsigned long) ptr;
		pte_t *pte;

		if (vaddr < FIXADDR_START)
		return virt_to_page(ptr);

		idx = virt_to_fix(vaddr);
		pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
		return pte_page(*pte);
		}

		#define flush_cache_kmaps() { flush_icache(); flush_dcache(); }

		#endif /* __KERNEL__ */

		#endif /* _ASM_HIGHMEM_H */

arch/microblaze/mm/Makefile

+1 −0

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		@@ -5,3 +5,4 @@
		obj-y := consistent.o init.o

		obj-$(CONFIG_MMU) += pgtable.o mmu_context.o fault.o
		obj-$(CONFIG_HIGHMEM) += highmem.o

arch/microblaze/mm/highmem.c

0 → 100644

+88 −0

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		/*
		* highmem.c: virtual kernel memory mappings for high memory
		*
		* PowerPC version, stolen from the i386 version.
		*
		* Used in CONFIG_HIGHMEM systems for memory pages which
		* are not addressable by direct kernel virtual addresses.
		*
		* Copyright (C) 1999 Gerhard Wichert, Siemens AG
		* Gerhard.Wichert@pdb.siemens.de
		*
		*
		* Redesigned the x86 32-bit VM architecture to deal with
		* up to 16 Terrabyte physical memory. With current x86 CPUs
		* we now support up to 64 Gigabytes physical RAM.
		*
		* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
		*
		* Reworked for PowerPC by various contributors. Moved from
		* highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
		*/

		#include <linux/highmem.h>
		#include <linux/module.h>

		/*
		* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
		* gives a more generic (and caching) interface. But kmap_atomic can
		* be used in IRQ contexts, so in some (very limited) cases we need
		* it.
		*/
		#include <asm/tlbflush.h>

		void kmap_atomic_prot(struct page page, pgprot_t prot)
		{

		unsigned long vaddr;
		int idx, type;

		/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
		pagefault_disable();
		if (!PageHighMem(page))
		return page_address(page);


		type = kmap_atomic_idx_push();
		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)));
		#endif
		set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
		local_flush_tlb_page(NULL, vaddr);

		return (void *) vaddr;
		}
		EXPORT_SYMBOL(kmap_atomic_prot);

		void __kunmap_atomic(void *kvaddr)
		{
		unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
		int type;

		if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
		pagefault_enable();
		return;
		}

		type = kmap_atomic_idx();
		#ifdef CONFIG_DEBUG_HIGHMEM
		{
		unsigned int idx;

		idx = type + KM_TYPE_NR * smp_processor_id();
		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));

		/*
		* force other mappings to Oops if they'll try to access
		* this pte without first remap it
		*/
		pte_clear(&init_mm, vaddr, kmap_pte-idx);
		local_flush_tlb_page(NULL, vaddr);
		}
		#endif
		kmap_atomic_idx_pop();
		pagefault_enable();
		}
		EXPORT_SYMBOL(__kunmap_atomic);