From 9c93af1ede9418bb3f1b9dd442faf91ba796a0ff Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 8 Jan 2009 12:04:47 +0000 Subject: NOMMU: Rename ARM's struct vm_region Rename ARM's struct vm_region so that I can introduce my own global version for NOMMU. It's feasible that the ARM version may wish to use my global one instead. The NOMMU vm_region struct defines areas of the physical memory map that are under mmap. This may include chunks of RAM or regions of memory mapped devices, such as flash. It is also used to retain copies of file content so that shareable private memory mappings of files can be made. As such, it may be compatible with what is described in the banner comment for ARM's vm_region struct. Signed-off-by: David Howells --- arch/arm/mm/dma-mapping.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 6796001..310e479 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -71,7 +71,7 @@ static DEFINE_SPINLOCK(consistent_lock); * the amount of RAM found at boot time.) I would imagine that get_vm_area() * would have to initialise this each time prior to calling vm_region_alloc(). */ -struct vm_region { +struct arm_vm_region { struct list_head vm_list; unsigned long vm_start; unsigned long vm_end; @@ -79,20 +79,20 @@ struct vm_region { int vm_active; }; -static struct vm_region consistent_head = { +static struct arm_vm_region consistent_head = { .vm_list = LIST_HEAD_INIT(consistent_head.vm_list), .vm_start = CONSISTENT_BASE, .vm_end = CONSISTENT_END, }; -static struct vm_region * -vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp) +static struct arm_vm_region * +arm_vm_region_alloc(struct arm_vm_region *head, size_t size, gfp_t gfp) { unsigned long addr = head->vm_start, end = head->vm_end - size; unsigned long flags; - struct vm_region *c, *new; + struct arm_vm_region *c, *new; - new = kmalloc(sizeof(struct vm_region), gfp); + new = kmalloc(sizeof(struct arm_vm_region), gfp); if (!new) goto out; @@ -127,9 +127,9 @@ vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp) return NULL; } -static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr) +static struct arm_vm_region *arm_vm_region_find(struct arm_vm_region *head, unsigned long addr) { - struct vm_region *c; + struct arm_vm_region *c; list_for_each_entry(c, &head->vm_list, vm_list) { if (c->vm_active && c->vm_start == addr) @@ -149,7 +149,7 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, pgprot_t prot) { struct page *page; - struct vm_region *c; + struct arm_vm_region *c; unsigned long order; u64 mask = ISA_DMA_THRESHOLD, limit; @@ -214,7 +214,7 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, /* * Allocate a virtual address in the consistent mapping region. */ - c = vm_region_alloc(&consistent_head, size, + c = arm_vm_region_alloc(&consistent_head, size, gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); if (c) { pte_t *pte; @@ -311,13 +311,13 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size) { unsigned long flags, user_size, kern_size; - struct vm_region *c; + struct arm_vm_region *c; int ret = -ENXIO; user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; spin_lock_irqsave(&consistent_lock, flags); - c = vm_region_find(&consistent_head, (unsigned long)cpu_addr); + c = arm_vm_region_find(&consistent_head, (unsigned long)cpu_addr); spin_unlock_irqrestore(&consistent_lock, flags); if (c) { @@ -359,7 +359,7 @@ EXPORT_SYMBOL(dma_mmap_writecombine); */ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle) { - struct vm_region *c; + struct arm_vm_region *c; unsigned long flags, addr; pte_t *ptep; int idx; @@ -378,7 +378,7 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr size = PAGE_ALIGN(size); spin_lock_irqsave(&consistent_lock, flags); - c = vm_region_find(&consistent_head, (unsigned long)cpu_addr); + c = arm_vm_region_find(&consistent_head, (unsigned long)cpu_addr); if (!c) goto no_area; -- cgit v1.1 From 8feae13110d60cc6287afabc2887366b0eb226c2 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 8 Jan 2009 12:04:47 +0000 Subject: NOMMU: Make VMAs per MM as for MMU-mode linux Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: David Howells Tested-by: Mike Frysinger Acked-by: Paul Mundt --- arch/arm/include/asm/mmu.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/arm') diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h index 53099d4..b561584 100644 --- a/arch/arm/include/asm/mmu.h +++ b/arch/arm/include/asm/mmu.h @@ -24,7 +24,6 @@ typedef struct { * modified for 2.6 by Hyok S. Choi */ typedef struct { - struct vm_list_struct *vmlist; unsigned long end_brk; } mm_context_t; -- cgit v1.1