| From 1cf3447755f87f4c84aea5623cc7fe5f5b6af09d Mon Sep 17 00:00:00 2001 |
| From: "Michael J. Ruhl" <michael.j.ruhl@intel.com> |
| Date: Thu, 23 Jul 2020 21:15:46 -0700 |
| Subject: [PATCH] io-mapping: indicate mapping failure |
| |
| commit e0b3e0b1a04367fc15c07f44e78361545b55357c upstream. |
| |
| The !ATOMIC_IOMAP version of io_maping_init_wc will always return |
| success, even when the ioremap fails. |
| |
| Since the ATOMIC_IOMAP version returns NULL when the init fails, and |
| callers check for a NULL return on error this is unexpected. |
| |
| During a device probe, where the ioremap failed, a crash can look like |
| this: |
| |
| BUG: unable to handle page fault for address: 0000000000210000 |
| #PF: supervisor write access in kernel mode |
| #PF: error_code(0x0002) - not-present page |
| Oops: 0002 [#1] PREEMPT SMP |
| CPU: 0 PID: 177 Comm: |
| RIP: 0010:fill_page_dma [i915] |
| gen8_ppgtt_create [i915] |
| i915_ppgtt_create [i915] |
| intel_gt_init [i915] |
| i915_gem_init [i915] |
| i915_driver_probe [i915] |
| pci_device_probe |
| really_probe |
| driver_probe_device |
| |
| The remap failure occurred much earlier in the probe. If it had been |
| propagated, the driver would have exited with an error. |
| |
| Return NULL on ioremap failure. |
| |
| [akpm@linux-foundation.org: detect ioremap_wc() errors earlier] |
| |
| Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping") |
| Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Reviewed-by: Andrew Morton <akpm@linux-foundation.org> |
| Cc: Mike Rapoport <rppt@linux.ibm.com> |
| Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> |
| Cc: Chris Wilson <chris@chris-wilson.co.uk> |
| Cc: Daniel Vetter <daniel@ffwll.ch> |
| Cc: <stable@vger.kernel.org> |
| Link: http://lkml.kernel.org/r/20200721171936.81563-1-michael.j.ruhl@intel.com |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h |
| index 6e125e9b4187..b9c91d321240 100644 |
| --- a/include/linux/io-mapping.h |
| +++ b/include/linux/io-mapping.h |
| @@ -108,9 +108,12 @@ io_mapping_init_wc(struct io_mapping *iomap, |
| resource_size_t base, |
| unsigned long size) |
| { |
| + iomap->iomem = ioremap_wc(base, size); |
| + if (!iomap->iomem) |
| + return NULL; |
| + |
| iomap->base = base; |
| iomap->size = size; |
| - iomap->iomem = ioremap_wc(base, size); |
| #if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */ |
| iomap->prot = pgprot_noncached_wc(PAGE_KERNEL); |
| #elif defined(pgprot_writecombine) |
| -- |
| 2.27.0 |
| |