From b56108bb8290a3ff533441fff2dad195bbb761d8 Mon Sep 17 00:00:00 2001 From: HATAYAMA Daisuke Date: Wed, 19 Jun 2013 10:06:07 +1000 Subject: [PATCH] vmalloc: introduce remap_vmalloc_range_partial We want to allocate ELF note segment buffer on the 2nd kernel in vmalloc space and remap it to user-space in order to reduce the risk that memory allocation fails on system with huge number of CPUs and so with huge ELF note segment that exceeds 11-order block size. Although there's already remap_vmalloc_range for the purpose of remapping vmalloc memory to user-space, we need to specify user-space range via vma. Mmap on /proc/vmcore needs to remap range across multiple objects, so the interface that requires vma to cover full range is problematic. This patch introduces remap_vmalloc_range_partial that receives user-space range as a pair of base address and size and can be used for mmap on /proc/vmcore case. remap_vmalloc_range is rewritten using remap_vmalloc_range_partial. Signed-off-by: HATAYAMA Daisuke Cc: KOSAKI Motohiro Cc: Vivek Goyal Cc: Atsushi Kumagai Cc: Lisa Mitchell Cc: Zhang Yanfei Signed-off-by: Andrew Morton --- include/linux/vmalloc.h | 4 +++ mm/vmalloc.c | 63 ++++++++++++++++++++++++++++------------- 2 files changed, 48 insertions(+), 19 deletions(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 7d5773a99f20..dd0a2c810529 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -82,6 +82,10 @@ extern void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot); extern void vunmap(const void *addr); +extern int remap_vmalloc_range_partial(struct vm_area_struct *vma, + unsigned long uaddr, void *kaddr, + unsigned long size); + extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, unsigned long pgoff); void vmalloc_sync_all(void); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 3875fa2f0f60..d9a9f4f6ee07 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2148,42 +2148,44 @@ finished: } /** - * remap_vmalloc_range - map vmalloc pages to userspace - * @vma: vma to cover (map full range of vma) - * @addr: vmalloc memory - * @pgoff: number of pages into addr before first page to map + * remap_vmalloc_range_partial - map vmalloc pages to userspace + * @vma: vma to cover + * @uaddr: target user address to start at + * @kaddr: virtual address of vmalloc kernel memory + * @size: size of map area * * Returns: 0 for success, -Exxx on failure * - * This function checks that addr is a valid vmalloc'ed area, and - * that it is big enough to cover the vma. Will return failure if - * that criteria isn't met. + * This function checks that @kaddr is a valid vmalloc'ed area, + * and that it is big enough to cover the range starting at + * @uaddr in @vma. Will return failure if that criteria isn't + * met. * * Similar to remap_pfn_range() (see mm/memory.c) */ -int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, - unsigned long pgoff) +int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr, + void *kaddr, unsigned long size) { struct vm_struct *area; - unsigned long uaddr = vma->vm_start; - unsigned long usize = vma->vm_end - vma->vm_start; - if ((PAGE_SIZE-1) & (unsigned long)addr) + size = PAGE_ALIGN(size); + + if (((PAGE_SIZE-1) & (unsigned long)uaddr) || + ((PAGE_SIZE-1) & (unsigned long)kaddr)) return -EINVAL; - area = find_vm_area(addr); + area = find_vm_area(kaddr); if (!area) return -EINVAL; if (!(area->flags & VM_USERMAP)) return -EINVAL; - if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE) + if (kaddr + size > area->addr + area->size) return -EINVAL; - addr += pgoff << PAGE_SHIFT; do { - struct page *page = vmalloc_to_page(addr); + struct page *page = vmalloc_to_page(kaddr); int ret; ret = vm_insert_page(vma, uaddr, page); @@ -2191,14 +2193,37 @@ int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, return ret; uaddr += PAGE_SIZE; - addr += PAGE_SIZE; - usize -= PAGE_SIZE; - } while (usize > 0); + kaddr += PAGE_SIZE; + size -= PAGE_SIZE; + } while (size > 0); vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; return 0; } +EXPORT_SYMBOL(remap_vmalloc_range_partial); + +/** + * remap_vmalloc_range - map vmalloc pages to userspace + * @vma: vma to cover (map full range of vma) + * @addr: vmalloc memory + * @pgoff: number of pages into addr before first page to map + * + * Returns: 0 for success, -Exxx on failure + * + * This function checks that addr is a valid vmalloc'ed area, and + * that it is big enough to cover the vma. Will return failure if + * that criteria isn't met. + * + * Similar to remap_pfn_range() (see mm/memory.c) + */ +int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, + unsigned long pgoff) +{ + return remap_vmalloc_range_partial(vma, vma->vm_start, + addr + (pgoff << PAGE_SHIFT), + vma->vm_end - vma->vm_start); +} EXPORT_SYMBOL(remap_vmalloc_range); /* -- 2.39.5