54622f10a6
This adds relocatable kernel support for kdump. With this one can use the same regular kernel to capture the kdump. A signature (0xfeed1234) is passed in r6 from panic code to the next kernel through kexec_sequence and purgatory code. The signature is used to differentiate between kdump kernel and non-kdump kernels. The purgatory code compares the signature and sets the __kdump_flag in head_64.S. During the boot up, kernel code checks __kdump_flag and if it is set, the kernel will behave as relocatable kdump kernel. This kernel will boot at the address where it was loaded by kexec-tools ie. at the address reserved through crashkernel boot parameter. CONFIG_CRASH_DUMP depends on CONFIG_RELOCATABLE option to build kdump kernel as relocatable. So the same kernel can be used as production and kdump kernel. This patch incorporates the changes suggested by Paul Mackerras to avoid GOT use and to avoid two copies of the code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
121 lines
3.1 KiB
C
121 lines
3.1 KiB
C
/*
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* Code to handle transition of Linux booting another kernel.
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*
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* Copyright (C) 2002-2003 Eric Biederman <ebiederm@xmission.com>
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* GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
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* Copyright (C) 2005 IBM Corporation.
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/kexec.h>
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#include <linux/reboot.h>
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#include <linux/threads.h>
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#include <linux/lmb.h>
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#include <asm/machdep.h>
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#include <asm/prom.h>
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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if (ppc_md.machine_crash_shutdown)
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ppc_md.machine_crash_shutdown(regs);
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}
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/*
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* Do what every setup is needed on image and the
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* reboot code buffer to allow us to avoid allocations
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* later.
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*/
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int machine_kexec_prepare(struct kimage *image)
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{
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if (ppc_md.machine_kexec_prepare)
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return ppc_md.machine_kexec_prepare(image);
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/*
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* Fail if platform doesn't provide its own machine_kexec_prepare
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* implementation.
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*/
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return -ENOSYS;
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}
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void machine_kexec_cleanup(struct kimage *image)
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{
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if (ppc_md.machine_kexec_cleanup)
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ppc_md.machine_kexec_cleanup(image);
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}
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/*
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* Do not allocate memory (or fail in any way) in machine_kexec().
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* We are past the point of no return, committed to rebooting now.
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*/
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void machine_kexec(struct kimage *image)
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{
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if (ppc_md.machine_kexec)
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ppc_md.machine_kexec(image);
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else {
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/*
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* Fall back to normal restart if platform doesn't provide
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* its own kexec function, and user insist to kexec...
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*/
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machine_restart(NULL);
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}
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for(;;);
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}
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void __init reserve_crashkernel(void)
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{
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unsigned long long crash_size, crash_base;
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int ret;
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/* this is necessary because of lmb_phys_mem_size() */
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lmb_analyze();
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/* use common parsing */
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ret = parse_crashkernel(boot_command_line, lmb_phys_mem_size(),
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&crash_size, &crash_base);
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if (ret == 0 && crash_size > 0) {
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crashk_res.start = crash_base;
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crashk_res.end = crash_base + crash_size - 1;
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}
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if (crashk_res.end == crashk_res.start) {
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crashk_res.start = crashk_res.end = 0;
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return;
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}
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/* We might have got these values via the command line or the
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* device tree, either way sanitise them now. */
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crash_size = crashk_res.end - crashk_res.start + 1;
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#ifndef CONFIG_RELOCATABLE
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if (crashk_res.start != KDUMP_KERNELBASE)
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printk("Crash kernel location must be 0x%x\n",
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KDUMP_KERNELBASE);
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crashk_res.start = KDUMP_KERNELBASE;
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#endif
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crash_size = PAGE_ALIGN(crash_size);
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crashk_res.end = crashk_res.start + crash_size - 1;
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/* Crash kernel trumps memory limit */
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if (memory_limit && memory_limit <= crashk_res.end) {
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memory_limit = crashk_res.end + 1;
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printk("Adjusted memory limit for crashkernel, now 0x%lx\n",
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memory_limit);
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}
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printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
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"for crashkernel (System RAM: %ldMB)\n",
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(unsigned long)(crash_size >> 20),
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(unsigned long)(crashk_res.start >> 20),
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(unsigned long)(lmb_phys_mem_size() >> 20));
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lmb_reserve(crashk_res.start, crash_size);
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}
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int overlaps_crashkernel(unsigned long start, unsigned long size)
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{
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return (start + size) > crashk_res.start && start <= crashk_res.end;
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}
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