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powerpc/kdump: Override crash_free_reserved_phys_range to avoid freeing RTAS

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The crashkernel region will almost always overlap RTAS. If we free the
crashkernel region via "echo 0 > /sys/kernel/kexec_crash_size" then we will
free RTAS and the machine will crash in confusing and exciting ways.

Override crash_free_reserved_phys_range and check for overlap with RTAS.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Blanchard 2010-08-24 14:23:44 +00:00 committed by Benjamin Herrenschmidt
parent 64ff312876
commit d72e063bb3
1 changed files with 33 additions and 0 deletions
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33
arch/powerpc/kernel/crash_dump.c
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@ -19,6 +19,7 @@
#include <asm/prom.h>
#include <asm/firmware.h>
#include <asm/uaccess.h>
#include <asm/rtas.h>
#ifdef DEBUG
#include <asm/udbg.h>
@ -141,3 +142,35 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
return csize;
}
#ifdef CONFIG_PPC_RTAS
/*
* The crashkernel region will almost always overlap the RTAS region, so
* we have to be careful when shrinking the crashkernel region.
*/
void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
{
unsigned long addr;
const u32 *basep, *sizep;
unsigned int rtas_start = 0, rtas_end = 0;
basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);
sizep = of_get_property(rtas.dev, "rtas-size", NULL);
if (basep && sizep) {
rtas_start = *basep;
rtas_end = *basep + *sizep;
}
for (addr = begin; addr < end; addr += PAGE_SIZE) {
/* Does this page overlap with the RTAS region? */
if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))
continue;
ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT));
init_page_count(pfn_to_page(addr >> PAGE_SHIFT));
free_page((unsigned long)__va(addr));
totalram_pages++;
}
}
#endif