| From: Michael Schmitz <schmitzmic@gmail.com> |
| Date: Mon, 14 May 2018 23:10:53 +1200 |
| Subject: m68k/mm: Adjust VM area to be unmapped by gap size for __iounmap() |
| |
| commit 3f90f9ef2dda316d64e420d5d51ba369587ccc55 upstream. |
| |
| 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 <schmitzmic@gmail.com> |
| [geert: Minor commit description improvements] |
| [geert: This was fixed in 2.4.23, but not in 2.5.x] |
| Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/m68k/mm/kmap.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/arch/m68k/mm/kmap.c |
| +++ b/arch/m68k/mm/kmap.c |
| @@ -88,7 +88,8 @@ static inline void free_io_area(void *ad |
| 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; |
| } |