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powerpc/mm/32: Use page_is_ram to check for RAM

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On systems where there is MMIO space between different blocks of RAM in
the physical address space, __ioremap_caller did not allow mapping these
MMIO areas, because they were below the end RAM and thus considered RAM
as well.  Use the memblock-based page_is_ram function, which returns
false for such MMIO holes.

v2:
  Keep the check for p < virt_to_phys(high_memory). On 32-bit systems
  with high memory (memory above physical address 4GiB), the high memory
  is expected to be available though ioremap. The high_memory variable
  marks the end of low memory; comparing against it means that only
  ioremap requests for low RAM will be denied.
  Reported by Michael Ellerman.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Jonathan Neuschäfer 2018-03-28 02:25:42 +02:00 committed by Michael Ellerman
parent f65e67c7e3
commit 2bbf63264a
1 changed files with 1 additions and 0 deletions
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arch/powerpc/mm/pgtable_32.c
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@ -148,6 +148,7 @@ __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
* mem_init() sets high_memory so only do the check after that.
*/
if (slab_is_available() && (p < virt_to_phys(high_memory)) &&
page_is_ram(__phys_to_pfn(p)) &&
!(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
(unsigned long long)p, __builtin_return_address(0));