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authorAnton Vorontsov <avorontsov@ru.mvista.com>2008-12-17 10:09:10 +0000
committerPaul Mackerras <paulus@samba.org>2008-12-23 15:13:29 +1100
commit01695a9687e5a8d78589605037cc7828a5b67ac9 (patch)
tree3d7f4ed52b1bbaffd62e6d04aaefc2f5989e32e6 /arch/powerpc
parent6f29c3298b18216198631cbee01c349adecb225d (diff)
powerpc/32: Allow __ioremap on RAM addresses for kdump kernel
While for debugging it is good to catch bogus users of ioremap, though for kdump support it is more convenient to use __ioremap for copy_oldmem_page() (exactly as we do for PPC64 currently). Note that copy_oldmem_page() calls __ioremap with flags set to '0', so it should be safe with the regard to the caches. The other option is to use kmap_atomic_pfn()[1], but it will not work for kernels compiled without HIGHMEM. That is, on a board with 256MB RAM and crashkernel=64M@32M case, the !HIGHMEM capturing kernel maps 0-96M range, which does not include all the memory needed to capture the dump. And, obviously, accessing anything upper than 96M will cause faults. [1] http://ozlabs.org/pipermail/linuxppc-dev/2007-November/046747.html Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/mm/pgtable_32.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 341472440137..cd5609759d44 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -173,6 +173,7 @@ __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
if (p < 16*1024*1024)
p += _ISA_MEM_BASE;
+#ifndef CONFIG_CRASH_DUMP
/*
* Don't allow anybody to remap normal RAM that we're using.
* mem_init() sets high_memory so only do the check after that.
@@ -182,6 +183,7 @@ __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
(unsigned long long)p, __builtin_return_address(0));
return NULL;
}
+#endif
if (size == 0)
return NULL;