From 3f90f9ef2dda316d64e420d5d51ba369587ccc55 Mon Sep 17 00:00:00 2001 From: Michael Schmitz Date: Mon, 14 May 2018 23:10:53 +1200 Subject: m68k/mm: Adjust VM area to be unmapped by gap size for __iounmap() If 020/030 support is enabled, get_io_area() leaves an IO_SIZE gap between mappings which is added to the vm_struct representing the mapping. __ioremap() uses the actual requested size (after alignment), while __iounmap() is passed the size from the vm_struct. On 020/030, early termination descriptors are used to set up mappings of extent 'size', which are validated on unmapping. The unmapped gap of size IO_SIZE defeats the sanity check of the pmd tables, causing __iounmap() to loop forever on 030. On 040/060, unmapping of page table entries does not check for a valid mapping, so the umapping loop always completes there. Adjust size to be unmapped by the gap that had been added in the vm_struct prior. This fixes the hang in atari_platform_init() reported a long time ago, and a similar one reported by Finn recently (addressed by removing ioremap() use from the SWIM driver. Tested on my Falcon in 030 mode - untested but should work the same on 040/060 (the extra page tables cleared there would never have been set up anyway). Signed-off-by: Michael Schmitz [geert: Minor commit description improvements] [geert: This was fixed in 2.4.23, but not in 2.5.x] Signed-off-by: Geert Uytterhoeven Cc: stable@vger.kernel.org --- arch/m68k/mm/kmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/m68k/mm') diff --git a/arch/m68k/mm/kmap.c b/arch/m68k/mm/kmap.c index c2a38321c96d..3b420f6d8822 100644 --- a/arch/m68k/mm/kmap.c +++ b/arch/m68k/mm/kmap.c @@ -89,7 +89,8 @@ static inline void free_io_area(void *addr) for (p = &iolist ; (tmp = *p) ; p = &tmp->next) { if (tmp->addr == addr) { *p = tmp->next; - __iounmap(tmp->addr, tmp->size); + /* remove gap added in get_io_area() */ + __iounmap(tmp->addr, tmp->size - IO_SIZE); kfree(tmp); return; } -- cgit v1.2.3