microblaze: Highmem support
The first highmem implementation. Signed-off-by: Michal Simek <monstr@monstr.eu>hifive-unleashed-5.1
Michal Simek
parent
baab8a828d
commit
2f2f371f89
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@ -159,20 +159,18 @@ config XILINX_UNCACHED_SHADOW
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The feature requires the design to define the RAM memory controller
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window to be twice as large as the actual physical memory.
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config HIGHMEM_START_BOOL
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bool "Set high memory pool address"
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depends on ADVANCED_OPTIONS && HIGHMEM
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help
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This option allows you to set the base address of the kernel virtual
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area used to map high memory pages. This can be useful in
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optimizing the layout of kernel virtual memory.
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Say N here unless you know what you are doing.
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config HIGHMEM_START
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hex "Virtual start address of high memory pool" if HIGHMEM_START_BOOL
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config HIGHMEM
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bool "High memory support"
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depends on MMU
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default "0xfe000000"
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help
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The address space of Microblaze processors is only 4 Gigabytes large
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and it has to accommodate user address space, kernel address
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space as well as some memory mapped IO. That means that, if you
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have a large amount of physical memory and/or IO, not all of the
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memory can be "permanently mapped" by the kernel. The physical
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memory that is not permanently mapped is called "high memory".
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If unsure, say n.
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config LOWMEM_SIZE_BOOL
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bool "Set maximum low memory"
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@ -21,6 +21,10 @@
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#ifndef __ASSEMBLY__
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#include <linux/kernel.h>
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#include <asm/page.h>
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#ifdef CONFIG_HIGHMEM
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#include <linux/threads.h>
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#include <asm/kmap_types.h>
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#endif
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#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
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@ -44,6 +48,10 @@
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*/
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enum fixed_addresses {
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FIX_HOLE,
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#ifdef CONFIG_HIGHMEM
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FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
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FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * num_possible_cpus()) - 1,
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#endif
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__end_of_fixed_addresses
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};
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@ -0,0 +1,96 @@
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/*
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* highmem.h: virtual kernel memory mappings for high memory
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*
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* Used in CONFIG_HIGHMEM systems for memory pages which
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* are not addressable by direct kernel virtual addresses.
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*
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* Copyright (C) 1999 Gerhard Wichert, Siemens AG
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* Gerhard.Wichert@pdb.siemens.de
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*
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*
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* Redesigned the x86 32-bit VM architecture to deal with
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* up to 16 Terabyte physical memory. With current x86 CPUs
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* we now support up to 64 Gigabytes physical RAM.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*/
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#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#ifdef __KERNEL__
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/uaccess.h>
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#include <asm/fixmap.h>
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extern pte_t *kmap_pte;
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extern pgprot_t kmap_prot;
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extern pte_t *pkmap_page_table;
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/*
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* Right now we initialize only a single pte table. It can be extended
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* easily, subsequent pte tables have to be allocated in one physical
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* chunk of RAM.
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*/
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/*
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* We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
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* table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
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* and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
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* in case of 16K/64K/256K page sizes.
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*/
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#define PKMAP_ORDER PTE_SHIFT
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#define LAST_PKMAP (1 << PKMAP_ORDER)
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#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
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& PMD_MASK)
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#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
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#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
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#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
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extern void *kmap_high(struct page *page);
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extern void kunmap_high(struct page *page);
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extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
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extern void __kunmap_atomic(void *kvaddr);
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static inline void *kmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(page))
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return page_address(page);
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return kmap_high(page);
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}
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static inline void kunmap(struct page *page)
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{
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BUG_ON(in_interrupt());
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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static inline void *__kmap_atomic(struct page *page)
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{
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return kmap_atomic_prot(page, kmap_prot);
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}
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static inline struct page *kmap_atomic_to_page(void *ptr)
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{
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unsigned long idx, vaddr = (unsigned long) ptr;
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pte_t *pte;
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if (vaddr < FIXADDR_START)
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return virt_to_page(ptr);
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idx = virt_to_fix(vaddr);
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pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
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return pte_page(*pte);
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}
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#define flush_cache_kmaps() { flush_icache(); flush_dcache(); }
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#endif /* __KERNEL__ */
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#endif /* _ASM_HIGHMEM_H */
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@ -5,3 +5,4 @@
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obj-y := consistent.o init.o
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obj-$(CONFIG_MMU) += pgtable.o mmu_context.o fault.o
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obj-$(CONFIG_HIGHMEM) += highmem.o
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@ -0,0 +1,88 @@
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/*
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* highmem.c: virtual kernel memory mappings for high memory
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*
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* PowerPC version, stolen from the i386 version.
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*
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* Used in CONFIG_HIGHMEM systems for memory pages which
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* are not addressable by direct kernel virtual addresses.
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*
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* Copyright (C) 1999 Gerhard Wichert, Siemens AG
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* Gerhard.Wichert@pdb.siemens.de
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*
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*
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* Redesigned the x86 32-bit VM architecture to deal with
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* up to 16 Terrabyte physical memory. With current x86 CPUs
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* we now support up to 64 Gigabytes physical RAM.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*
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* Reworked for PowerPC by various contributors. Moved from
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* highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
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*/
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#include <linux/highmem.h>
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#include <linux/module.h>
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/*
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* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
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* gives a more generic (and caching) interface. But kmap_atomic can
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* be used in IRQ contexts, so in some (very limited) cases we need
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* it.
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*/
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#include <asm/tlbflush.h>
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void *kmap_atomic_prot(struct page *page, pgprot_t prot)
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{
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unsigned long vaddr;
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int idx, type;
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/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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type = kmap_atomic_idx_push();
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idx = type + KM_TYPE_NR*smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(!pte_none(*(kmap_pte-idx)));
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#endif
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set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
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local_flush_tlb_page(NULL, vaddr);
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return (void *) vaddr;
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}
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EXPORT_SYMBOL(kmap_atomic_prot);
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void __kunmap_atomic(void *kvaddr)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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int type;
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if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
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pagefault_enable();
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return;
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}
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type = kmap_atomic_idx();
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#ifdef CONFIG_DEBUG_HIGHMEM
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{
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unsigned int idx;
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idx = type + KM_TYPE_NR * smp_processor_id();
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BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
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/*
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* force other mappings to Oops if they'll try to access
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* this pte without first remap it
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*/
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pte_clear(&init_mm, vaddr, kmap_pte-idx);
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local_flush_tlb_page(NULL, vaddr);
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}
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#endif
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kmap_atomic_idx_pop();
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pagefault_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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@ -49,6 +49,53 @@ unsigned long memory_size;
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EXPORT_SYMBOL(memory_size);
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unsigned long lowmem_size;
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#ifdef CONFIG_HIGHMEM
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pte_t *kmap_pte;
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EXPORT_SYMBOL(kmap_pte);
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pgprot_t kmap_prot;
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EXPORT_SYMBOL(kmap_prot);
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static inline pte_t *virt_to_kpte(unsigned long vaddr)
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{
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return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
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vaddr), vaddr);
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}
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static void __init highmem_init(void)
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{
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pr_debug("%x\n", (u32)PKMAP_BASE);
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map_page(PKMAP_BASE, 0, 0); /* XXX gross */
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pkmap_page_table = virt_to_kpte(PKMAP_BASE);
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kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
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kmap_prot = PAGE_KERNEL;
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}
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static unsigned long highmem_setup(void)
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{
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unsigned long pfn;
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unsigned long reservedpages = 0;
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for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
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struct page *page = pfn_to_page(pfn);
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/* FIXME not sure about */
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if (memblock_is_reserved(pfn << PAGE_SHIFT))
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continue;
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ClearPageReserved(page);
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init_page_count(page);
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__free_page(page);
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totalhigh_pages++;
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reservedpages++;
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}
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totalram_pages += totalhigh_pages;
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printk(KERN_INFO "High memory: %luk\n",
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totalhigh_pages << (PAGE_SHIFT-10));
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return reservedpages;
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}
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#endif /* CONFIG_HIGHMEM */
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/*
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* paging_init() sets up the page tables - in fact we've already done this.
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*/
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@ -66,7 +113,14 @@ static void __init paging_init(void)
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/* Clean every zones */
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memset(zones_size, 0, sizeof(zones_size));
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#ifdef CONFIG_HIGHMEM
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highmem_init();
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zones_size[ZONE_DMA] = max_low_pfn;
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zones_size[ZONE_HIGHMEM] = max_pfn;
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#else
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zones_size[ZONE_DMA] = max_pfn;
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#endif
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/* We don't have holes in memory map */
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free_area_init_nodes(zones_size);
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@ -241,6 +295,10 @@ void __init mem_init(void)
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}
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}
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#ifdef CONFIG_HIGHMEM
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reservedpages -= highmem_setup();
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#endif
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codesize = (unsigned long)&_sdata - (unsigned long)&_stext;
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datasize = (unsigned long)&_edata - (unsigned long)&_sdata;
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initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
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@ -259,6 +317,10 @@ void __init mem_init(void)
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#ifdef CONFIG_MMU
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pr_info("Kernel virtual memory layout:\n");
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pr_info(" * 0x%08lx..0x%08lx : fixmap\n", FIXADDR_START, FIXADDR_TOP);
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#ifdef CONFIG_HIGHMEM
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pr_info(" * 0x%08lx..0x%08lx : highmem PTEs\n",
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PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
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#endif /* CONFIG_HIGHMEM */
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pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
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ioremap_bot, ioremap_base);
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pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n",
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@ -346,7 +408,9 @@ asmlinkage void __init mmu_init(void)
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if (lowmem_size > CONFIG_LOWMEM_SIZE) {
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lowmem_size = CONFIG_LOWMEM_SIZE;
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#ifndef CONFIG_HIGHMEM
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memory_size = lowmem_size;
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#endif
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}
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mm_cmdline_setup(); /* FIXME parse args from command line - not used */
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@ -375,7 +439,11 @@ asmlinkage void __init mmu_init(void)
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mapin_ram();
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/* Extend vmalloc and ioremap area as big as possible */
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#ifdef CONFIG_HIGHMEM
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ioremap_base = ioremap_bot = PKMAP_BASE;
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#else
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ioremap_base = ioremap_bot = FIXADDR_START;
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#endif
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/* Initialize the context management stuff */
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mmu_context_init();
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