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Commit 66c721e1 authored by Milton Miller's avatar Milton Miller Committed by Benjamin Herrenschmidt
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powerpc/kexec: Check crash_base for relocatable kernel 



Enforce that the crash kernel region never overlaps the current kernel,
as it will be written directly on kexec load.

Also, default to the previous KDUMP_KERNELBASE if the start is 0.

Other architectures (x86, ia64) state that specifying the start address
0 (or omitting it) will result in the kernel allocating it.  Before the
relocatable patch in 2.6.28, powerpc would adjust any other start value
to the hardcoded KDUMP_KERNELBASE of 32M.

Signed-off-by: default avatarMilton Miller <miltonm@bga.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent e16459c6

arch/powerpc/kernel/machine_kexec.c

+25 −0
Original line number Diff line number Diff line
@@ -93,10 +93,35 @@ void __init reserve_crashkernel(void) 
				KDUMP_KERNELBASE);



	crashk_res.start = KDUMP_KERNELBASE;

#else

	if (!crashk_res.start) {

		/*

		 * unspecified address, choose a region of specified size

		 * can overlap with initrd (ignoring corruption when retained)

		 * ppc64 requires kernel and some stacks to be in first segemnt

		 */

		crashk_res.start = KDUMP_KERNELBASE;

	}



	crash_base = PAGE_ALIGN(crashk_res.start);

	if (crash_base != crashk_res.start) {

		printk("Crash kernel base must be aligned to 0x%lx\n",

				PAGE_SIZE);

		crashk_res.start = crash_base;

	}



#endif

	crash_size = PAGE_ALIGN(crash_size);

	crashk_res.end = crashk_res.start + crash_size - 1;



	/* The crash region must not overlap the current kernel */

	if (overlaps_crashkernel(__pa(_stext), _end - _stext)) {

		printk(KERN_WARNING

			"Crash kernel can not overlap current kernel\n");

		crashk_res.start = crashk_res.end = 0;

		return;

	}



	/* Crash kernel trumps memory limit */

	if (memory_limit && memory_limit <= crashk_res.end) {

		memory_limit = crashk_res.end + 1;