[PATCH] NOMMU: Work around the lack of vmap()/vunmap() in firmware_loading_store() [ver #2]
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From: David Howells on 8 Apr 2010 10:00 Work around the lack of vmap()/vunmap() in firmware_loading_store() when operating in NOMMU mode. vmap() cannot be implemented as there's no virtual mapping available. Instead, in NOMMU mode, make available a function (vcoalesce()) that can coalesce the supplied data into one big buffer and store as the address vmap() would've returned. This can be #defined to vmap() in NOMMU mode by interested parties. Signed-off-by: David Howells <dhowells(a)redhat.com> --- drivers/base/firmware_class.c | 8 ++++++++ include/linux/vmalloc.h | 1 + mm/nommu.c | 24 ++++++++++++++++++++++++ 3 files changed, 33 insertions(+), 0 deletions(-) diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index 985da11..be71e54 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -60,6 +60,14 @@ static struct builtin_fw *__start_builtin_fw; static struct builtin_fw *__end_builtin_fw; #endif +/* + * NOMMU mode can't provide vmap() as there's no MMU to do the virtual mapping. + * Coalesce the data into a big buffer instead. + */ +#ifndef CONFIG_MMU +#define vmap(pg, c, f, pr) vcoalesce(pg, c, f, pr) +#endif + static void fw_load_abort(struct firmware_priv *fw_priv) { diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 227c2a5..f36a4b2 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -48,6 +48,7 @@ extern void __init vmalloc_init(void); static inline void vmalloc_init(void) { } +extern void *vcoalesce(struct page **, unsigned int, unsigned long, pgprot_t); #endif extern void *vmalloc(unsigned long size); diff --git a/mm/nommu.c b/mm/nommu.c index 63fa17d..05a5c63 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -405,6 +405,30 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, EXPORT_SYMBOL(vm_insert_page); /* + * NOMMU mode can't provide vmap() as there's no MMU to do the virtual mapping. + * Provide a facility to coalesce the data into a big buffer instead. + */ +void *vcoalesce(struct page **pages, unsigned int count, + unsigned long flags, pgprot_t prot) +{ + unsigned int i; + void *new_map, *page_data; + + new_map = kmalloc(count << PAGE_SHIFT, GFP_KERNEL); + if (!new_map) + return NULL; + + for (i = 0; i < count; ++i) { + page_data = kmap(pages[i]); + memcpy(new_map + (i << PAGE_SHIFT), page_data, PAGE_SIZE); + kunmap(page_data); + } + + return new_map; +} +EXPORT_SYMBOL(vcoalesce); + +/* * sys_brk() for the most part doesn't need the global kernel * lock, except when an application is doing something nasty * like trying to un-brk an area that has already been mapped -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |