From 59bd00c85012af2b59ba8c1b47caaf10ccbfa3b1 Mon Sep 17 00:00:00 2001 From: Thomas Chou Date: Sun, 27 Sep 2009 15:38:01 +0800 Subject: [PATCH] Blackfin: fix framebuffer mmap bug for nommu The patch added a special get_unmapped_area for framebuffer which was hooked to the file ops in drivers/video/fbmem.c. This is needed since v2.6.29-rc1 where nommu vma management was updated, and mmap of framebuffer caused kernel BUG panic. You may turn on "Debug the global anon/private NOMMU mapping region tree" config to such message. As Documentation/nommu-mmap.txt said, "To provide shareable character device support, a driver must provide a file->f_op->get_unmapped_area() operation. The mmap() routines will call this to get a proposed address for the mapping." With this change, user space should call mmap for framebuffer using shared map. Or it can try shared map first, then private map if failed. This shared map usage is now consistent between mmu and nommu. The sys_ file may not be a good place for this patch. But there is a similar one for sparc. I tested a similar patch on nios2nommu, though I don't have a blackfin board to test. Signed-off-by: Thomas Chou Signed-off-by: Graf Yang Signed-off-by: Michael Hennerich Signed-off-by: Mike Frysinger --- arch/blackfin/include/asm/pgtable.h | 6 ++++++ arch/blackfin/kernel/sys_bfin.c | 11 +++++++++++ 2 files changed, 17 insertions(+) diff --git a/arch/blackfin/include/asm/pgtable.h b/arch/blackfin/include/asm/pgtable.h index b54cbddf547..821c699c223 100644 --- a/arch/blackfin/include/asm/pgtable.h +++ b/arch/blackfin/include/asm/pgtable.h @@ -98,6 +98,12 @@ extern unsigned int kobjsize(const void *objp); #define VMALLOC_START 0 #define VMALLOC_END 0xffffffff +/* provide a special get_unmapped_area for framebuffer mmaps of nommu */ +extern unsigned long get_fb_unmapped_area(struct file *filp, unsigned long, + unsigned long, unsigned long, + unsigned long); +#define HAVE_ARCH_FB_UNMAPPED_AREA + #include #endif /* _BLACKFIN_PGTABLE_H */ diff --git a/arch/blackfin/kernel/sys_bfin.c b/arch/blackfin/kernel/sys_bfin.c index 8b294a1c806..afcef129d4e 100644 --- a/arch/blackfin/kernel/sys_bfin.c +++ b/arch/blackfin/kernel/sys_bfin.c @@ -69,3 +69,14 @@ asmlinkage void *sys_dma_memcpy(void *dest, const void *src, size_t len) { return safe_dma_memcpy(dest, src, len); } + +#if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE) +#include +unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, + unsigned long len, unsigned long pgoff, unsigned long flags) +{ + struct fb_info *info = filp->private_data; + return (unsigned long)info->screen_base; +} +EXPORT_SYMBOL(get_fb_unmapped_area); +#endif