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![Michael J. Ruhl](/assets/img/avatar_default.png)
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: cafaf14a5d
("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>
192 lines
3.7 KiB
C
192 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright © 2008 Keith Packard <keithp@keithp.com>
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*/
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#ifndef _LINUX_IO_MAPPING_H
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#define _LINUX_IO_MAPPING_H
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/bug.h>
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#include <linux/io.h>
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#include <linux/pgtable.h>
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#include <asm/page.h>
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/*
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* The io_mapping mechanism provides an abstraction for mapping
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* individual pages from an io device to the CPU in an efficient fashion.
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*
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* See Documentation/driver-api/io-mapping.rst
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*/
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struct io_mapping {
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resource_size_t base;
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unsigned long size;
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pgprot_t prot;
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void __iomem *iomem;
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};
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#ifdef CONFIG_HAVE_ATOMIC_IOMAP
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#include <linux/pfn.h>
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#include <asm/iomap.h>
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/*
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* For small address space machines, mapping large objects
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* into the kernel virtual space isn't practical. Where
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* available, use fixmap support to dynamically map pages
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* of the object at run time.
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*/
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static inline struct io_mapping *
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io_mapping_init_wc(struct io_mapping *iomap,
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resource_size_t base,
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unsigned long size)
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{
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pgprot_t prot;
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if (iomap_create_wc(base, size, &prot))
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return NULL;
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iomap->base = base;
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iomap->size = size;
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iomap->prot = prot;
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return iomap;
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}
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static inline void
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io_mapping_fini(struct io_mapping *mapping)
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{
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iomap_free(mapping->base, mapping->size);
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}
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/* Atomic map/unmap */
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static inline void __iomem *
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io_mapping_map_atomic_wc(struct io_mapping *mapping,
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unsigned long offset)
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{
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resource_size_t phys_addr;
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BUG_ON(offset >= mapping->size);
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phys_addr = mapping->base + offset;
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return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot);
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}
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static inline void
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io_mapping_unmap_atomic(void __iomem *vaddr)
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{
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iounmap_atomic(vaddr);
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}
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static inline void __iomem *
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io_mapping_map_wc(struct io_mapping *mapping,
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unsigned long offset,
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unsigned long size)
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{
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resource_size_t phys_addr;
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BUG_ON(offset >= mapping->size);
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phys_addr = mapping->base + offset;
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return ioremap_wc(phys_addr, size);
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}
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static inline void
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io_mapping_unmap(void __iomem *vaddr)
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{
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iounmap(vaddr);
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}
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#else
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#include <linux/uaccess.h>
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/* Create the io_mapping object*/
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static inline struct io_mapping *
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io_mapping_init_wc(struct io_mapping *iomap,
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resource_size_t base,
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unsigned long size)
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{
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iomap->iomem = ioremap_wc(base, size);
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if (!iomap->iomem)
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return NULL;
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iomap->base = base;
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iomap->size = size;
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#if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */
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iomap->prot = pgprot_noncached_wc(PAGE_KERNEL);
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#elif defined(pgprot_writecombine)
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iomap->prot = pgprot_writecombine(PAGE_KERNEL);
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#else
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iomap->prot = pgprot_noncached(PAGE_KERNEL);
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#endif
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return iomap;
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}
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static inline void
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io_mapping_fini(struct io_mapping *mapping)
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{
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iounmap(mapping->iomem);
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}
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/* Non-atomic map/unmap */
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static inline void __iomem *
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io_mapping_map_wc(struct io_mapping *mapping,
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unsigned long offset,
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unsigned long size)
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{
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return mapping->iomem + offset;
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}
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static inline void
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io_mapping_unmap(void __iomem *vaddr)
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{
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}
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/* Atomic map/unmap */
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static inline void __iomem *
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io_mapping_map_atomic_wc(struct io_mapping *mapping,
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unsigned long offset)
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{
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preempt_disable();
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pagefault_disable();
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return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
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}
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static inline void
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io_mapping_unmap_atomic(void __iomem *vaddr)
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{
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io_mapping_unmap(vaddr);
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pagefault_enable();
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preempt_enable();
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}
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#endif /* HAVE_ATOMIC_IOMAP */
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static inline struct io_mapping *
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io_mapping_create_wc(resource_size_t base,
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unsigned long size)
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{
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struct io_mapping *iomap;
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iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
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if (!iomap)
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return NULL;
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if (!io_mapping_init_wc(iomap, base, size)) {
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kfree(iomap);
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return NULL;
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}
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return iomap;
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}
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static inline void
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io_mapping_free(struct io_mapping *iomap)
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{
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io_mapping_fini(iomap);
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kfree(iomap);
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}
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#endif /* _LINUX_IO_MAPPING_H */
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