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Commit d72e063b authored by Anton Blanchard's avatar Anton Blanchard Committed by Benjamin Herrenschmidt
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powerpc/kdump: Override crash_free_reserved_phys_range to avoid freeing RTAS 



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: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 64ff3128

arch/powerpc/kernel/crash_dump.c

+33 −0
Original line number Diff line number Diff line
@@ -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