From 7856dfeb23c16ef3d8dac8871b4d5b93c70b59b9 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 20 May 2005 14:27:57 -0700 Subject: [PATCH] [PATCH] x86_64: Fixed guard page handling again in iounmap Caused oopses again. Also fix potential mismatch in checking if change_page_attr was needed. To do it without races I needed to change mm/vmalloc.c to export a __remove_vm_area that does not take vmlist lock. Noticed by Terence Ripperda and based on a patch of his. Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/mm/ioremap.c | 29 ++++++++--------------------- include/linux/vmalloc.h | 1 + mm/vmalloc.c | 33 ++++++++++++++++++++------------- 3 files changed, 29 insertions(+), 34 deletions(-) diff --git a/arch/x86_64/mm/ioremap.c b/arch/x86_64/mm/ioremap.c index c6fb0cb699..58aac23760 100644 --- a/arch/x86_64/mm/ioremap.c +++ b/arch/x86_64/mm/ioremap.c @@ -133,7 +133,7 @@ ioremap_change_attr(unsigned long phys_addr, unsigned long size, unsigned long flags) { int err = 0; - if (flags && phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) { + if (phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) { unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; unsigned long vaddr = (unsigned long) __va(phys_addr); @@ -214,7 +214,7 @@ void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned l remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr)); return NULL; } - if (ioremap_change_attr(phys_addr, size, flags) < 0) { + if (flags && ioremap_change_attr(phys_addr, size, flags) < 0) { area->flags &= 0xffffff; vunmap(addr); return NULL; @@ -251,7 +251,7 @@ void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size) void iounmap(volatile void __iomem *addr) { - struct vm_struct *p, **pprev; + struct vm_struct *p; if (addr <= high_memory) return; @@ -260,24 +260,11 @@ void iounmap(volatile void __iomem *addr) return; write_lock(&vmlist_lock); - for (p = vmlist, pprev = &vmlist; p != NULL; pprev = &p->next, p = *pprev) - if (p->addr == (void *)(PAGE_MASK & (unsigned long)addr)) - break; - if (!p) { - printk("__iounmap: bad address %p\n", addr); - goto out_unlock; - } - *pprev = p->next; - unmap_vm_area(p); - if ((p->flags >> 20) && - p->phys_addr + p->size - 1 < virt_to_phys(high_memory)) { - /* p->size includes the guard page, but cpa doesn't like that */ - change_page_attr_addr((unsigned long)__va(p->phys_addr), - p->size >> PAGE_SHIFT, - PAGE_KERNEL); - global_flush_tlb(); - } -out_unlock: + p = __remove_vm_area((void *)((unsigned long)addr & PAGE_MASK)); + if (!p) + printk("iounmap: bad address %p\n", addr); + else if (p->flags >> 20) + ioremap_change_attr(p->phys_addr, p->size, 0); write_unlock(&vmlist_lock); kfree(p); } diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 3a358c8951..6409d9cf59 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -41,6 +41,7 @@ extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags); extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, unsigned long start, unsigned long end); extern struct vm_struct *remove_vm_area(void *addr); +extern struct vm_struct *__remove_vm_area(void *addr); extern int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages); extern void unmap_vm_area(struct vm_struct *area); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 2bd83e5c2b..8ff16a1eee 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -248,31 +248,20 @@ struct vm_struct *get_vm_area(unsigned long size, unsigned long flags) return __get_vm_area(size, flags, VMALLOC_START, VMALLOC_END); } -/** - * remove_vm_area - find and remove a contingous kernel virtual area - * - * @addr: base address - * - * Search for the kernel VM area starting at @addr, and remove it. - * This function returns the found VM area, but using it is NOT safe - * on SMP machines. - */ -struct vm_struct *remove_vm_area(void *addr) +/* Caller must hold vmlist_lock */ +struct vm_struct *__remove_vm_area(void *addr) { struct vm_struct **p, *tmp; - write_lock(&vmlist_lock); for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) { if (tmp->addr == addr) goto found; } - write_unlock(&vmlist_lock); return NULL; found: unmap_vm_area(tmp); *p = tmp->next; - write_unlock(&vmlist_lock); /* * Remove the guard page. @@ -281,6 +270,24 @@ found: return tmp; } +/** + * remove_vm_area - find and remove a contingous kernel virtual area + * + * @addr: base address + * + * Search for the kernel VM area starting at @addr, and remove it. + * This function returns the found VM area, but using it is NOT safe + * on SMP machines, except for its size or flags. + */ +struct vm_struct *remove_vm_area(void *addr) +{ + struct vm_struct *v; + write_lock(&vmlist_lock); + v = __remove_vm_area(addr); + write_unlock(&vmlist_lock); + return v; +} + void __vunmap(void *addr, int deallocate_pages) { struct vm_struct *area; -- 2.39.5