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From: Anton Vorontsov <avorontsov@ru•mvista.com>
To: linuxppc-dev@ozlabs•org
Cc: Paul Mackerras <paulus@samba•org>
Subject: [PATCH 5/8] powerpc: allow to ioremap RAM addresses for kdump kernel on ppc32
Date: Fri, 1 Aug 2008 18:14:23 +0400	[thread overview]
Message-ID: <20080801141423.GE1161@polina.dev.rtsoft.ru> (raw)
In-Reply-To: <20080801141306.GA29127@polina.dev.rtsoft.ru>

While for debugging it is good to catch bogus users of ioremap, but
for kdump support it is more convenient to use ioremap for
copy_oldmem_page() (exactly as we do for PPC64 currently).

The other option is to use kmap_atomic_pfn()*, 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.

* http://ozlabs.org/pipermail/linuxppc-dev/2007-November/046747.html

Signed-off-by: Anton Vorontsov <avorontsov@ru•mvista.com>
---
 arch/powerpc/mm/pgtable_32.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index ea50968..3e69b0d 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -194,6 +194,7 @@ __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.
@@ -203,6 +204,7 @@ __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;
-- 
1.5.5.4

  parent reply	other threads:[~2008-08-01 14:14 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-01 14:13 [RFC][PATCH 0/8] kexec/kdump support for ppc32 Anton Vorontsov
2008-08-01 14:14 ` [PATCH 1/8] powerpc: set up OF properties for ppc32 kexec Anton Vorontsov
2008-08-07 10:44   ` Michael Ellerman
2008-08-01 14:14 ` [PATCH 2/8] powerpc: make default kexec/crash_kernel ops implicit Anton Vorontsov
2008-08-01 14:14 ` [PATCH 3/8] powerpc: remove default kexec/crash_kernel ops assignments Anton Vorontsov
2008-08-01 14:14 ` [PATCH 4/8] powerpc: add the ability for a classic ppc kernel to be loaded at 32M Anton Vorontsov
2008-08-01 18:49   ` Scott Wood
2008-08-01 20:38     ` Anton Vorontsov
2008-08-20  4:57       ` Paul Mackerras
2008-08-01 14:14 ` Anton Vorontsov [this message]
2008-08-01 14:14 ` [PATCH 6/8] powerpc: set up OF properties for ppc32 kdump Anton Vorontsov
2008-08-07 10:47   ` Michael Ellerman
2008-08-07 11:11     ` Anton Vorontsov
2008-08-01 14:14 ` [PATCH 7/8] powerpc: implement crash_setup_regs for ppc32 Anton Vorontsov
2008-08-07 10:32   ` Michael Ellerman
2008-08-01 14:14 ` [PATCH 8/8] powerpc: last bits to support kdump on ppc32 Anton Vorontsov
2008-08-03 14:40   ` Michael Ellerman
2008-08-01 14:21 ` [RFC][PATCH 0/8] kexec/kdump support for ppc32 Kumar Gala
2008-08-01 14:46   ` Anton Vorontsov

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