1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 *
 14 * based on machine_kexec.c from other architectures in linux-2.6.18
 15 */
 16
 17#include <linux/mm.h>
 18#include <linux/kexec.h>
 19#include <linux/delay.h>
 20#include <linux/reboot.h>
 21#include <linux/errno.h>
 22#include <linux/vmalloc.h>
 23#include <linux/cpumask.h>
 24#include <linux/kernel.h>
 25#include <linux/elf.h>
 26#include <linux/highmem.h>
 27#include <linux/mmu_context.h>
 28#include <linux/io.h>
 29#include <linux/timex.h>
 30#include <asm/pgtable.h>
 31#include <asm/pgalloc.h>
 32#include <asm/cacheflush.h>
 33#include <asm/checksum.h>
 34#include <hv/hypervisor.h>
 35
 36
 37/*
 38 * This stuff is not in elf.h and is not in any other kernel include.
 39 * This stuff is needed below in the little boot notes parser to
 40 * extract the command line so we can pass it to the hypervisor.
 41 */
 42struct Elf32_Bhdr {
 43	Elf32_Word b_signature;
 44	Elf32_Word b_size;
 45	Elf32_Half b_checksum;
 46	Elf32_Half b_records;
 47};
 48#define ELF_BOOT_MAGIC		0x0E1FB007
 49#define EBN_COMMAND_LINE	0x00000004
 50#define roundupsz(X) (((X) + 3) & ~3)
 51
 52/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 53
 54
 55void machine_shutdown(void)
 56{
 57	/*
 58	 * Normally we would stop all the other processors here, but
 59	 * the check in machine_kexec_prepare below ensures we'll only
 60	 * get this far if we've been booted with "nosmp" on the
 61	 * command line or without CONFIG_SMP so there's nothing to do
 62	 * here (for now).
 63	 */
 64}
 65
 66void machine_crash_shutdown(struct pt_regs *regs)
 67{
 68	/*
 69	 * Cannot happen.  This type of kexec is disabled on this
 70	 * architecture (and enforced in machine_kexec_prepare below).
 71	 */
 72}
 73
 74
 75int machine_kexec_prepare(struct kimage *image)
 76{
 77	if (num_online_cpus() > 1) {
 78		pr_warning("%s: detected attempt to kexec "
 79		       "with num_online_cpus() > 1\n",
 80		       __func__);
 81		return -ENOSYS;
 82	}
 83	if (image->type != KEXEC_TYPE_DEFAULT) {
 84		pr_warning("%s: detected attempt to kexec "
 85		       "with unsupported type: %d\n",
 86		       __func__,
 87		       image->type);
 88		return -ENOSYS;
 89	}
 90	return 0;
 91}
 92
 93void machine_kexec_cleanup(struct kimage *image)
 94{
 95	/*
 96	 * We did nothing in machine_kexec_prepare,
 97	 * so we have nothing to do here.
 98	 */
 99}
100
101/*
102 * If we can find elf boot notes on this page, return the command
103 * line.  Otherwise, silently return null.  Somewhat kludgy, but no
104 * good way to do this without significantly rearchitecting the
105 * architecture-independent kexec code.
106 */
107
108static unsigned char *kexec_bn2cl(void *pg)
109{
110	struct Elf32_Bhdr *bhdrp;
111	Elf32_Nhdr *nhdrp;
112	unsigned char *desc;
113	unsigned char *command_line;
114	__sum16 csum;
115
116	bhdrp = (struct Elf32_Bhdr *) pg;
117
118	/*
119	 * This routine is invoked for every source page, so make
120	 * sure to quietly ignore every impossible page.
121	 */
122	if (bhdrp->b_signature != ELF_BOOT_MAGIC ||
123	    bhdrp->b_size > PAGE_SIZE)
124		return 0;
125
126	/*
127	 * If we get a checksum mismatch, warn with the checksum
128	 * so we can diagnose better.
129	 */
130	csum = ip_compute_csum(pg, bhdrp->b_size);
131	if (csum != 0) {
132		pr_warning("%s: bad checksum %#x (size %d)\n",
133			   __func__, csum, bhdrp->b_size);
134		return 0;
135	}
136
137	nhdrp = (Elf32_Nhdr *) (bhdrp + 1);
138
139	while (nhdrp->n_type != EBN_COMMAND_LINE) {
140
141		desc = (unsigned char *) (nhdrp + 1);
142		desc += roundupsz(nhdrp->n_descsz);
143
144		nhdrp = (Elf32_Nhdr *) desc;
145
146		/* still in bounds? */
147		if ((unsigned char *) (nhdrp + 1) >
148		    ((unsigned char *) pg) + bhdrp->b_size) {
149
150			pr_info("%s: out of bounds\n", __func__);
151			return 0;
152		}
153	}
154
155	command_line = (unsigned char *) (nhdrp + 1);
156	desc = command_line;
157
158	while (*desc != '\0') {
159		desc++;
160		if (((unsigned long)desc & PAGE_MASK) != (unsigned long)pg) {
161			pr_info("%s: ran off end of page\n",
162			       __func__);
163			return 0;
164		}
165	}
166
167	return command_line;
168}
169
170static void kexec_find_and_set_command_line(struct kimage *image)
171{
172	kimage_entry_t *ptr, entry;
173
174	unsigned char *command_line = 0;
175	unsigned char *r;
176	HV_Errno hverr;
177
178	for (ptr = &image->head;
179	     (entry = *ptr) && !(entry & IND_DONE);
180	     ptr = (entry & IND_INDIRECTION) ?
181		     phys_to_virt((entry & PAGE_MASK)) : ptr + 1) {
182
183		if ((entry & IND_SOURCE)) {
184			void *va =
185				kmap_atomic_pfn(entry >> PAGE_SHIFT);
186			r = kexec_bn2cl(va);
187			if (r) {
188				command_line = r;
189				break;
190			}
191			kunmap_atomic(va);
192		}
193	}
194
195	if (command_line != 0) {
196		pr_info("setting new command line to \"%s\"\n",
197		       command_line);
198
199		hverr = hv_set_command_line(
200			(HV_VirtAddr) command_line, strlen(command_line));
201		kunmap_atomic(command_line);
202	} else {
203		pr_info("%s: no command line found; making empty\n",
204		       __func__);
205		hverr = hv_set_command_line((HV_VirtAddr) command_line, 0);
206	}
207	if (hverr)
208		pr_warning("%s: hv_set_command_line returned error: %d\n",
209			   __func__, hverr);
210}
211
212/*
213 * The kexec code range-checks all its PAs, so to avoid having it run
214 * amok and allocate memory and then sequester it from every other
215 * controller, we force it to come from controller zero.  We also
216 * disable the oom-killer since if we do end up running out of memory,
217 * that almost certainly won't help.
218 */
219struct page *kimage_alloc_pages_arch(gfp_t gfp_mask, unsigned int order)
220{
221	gfp_mask |= __GFP_THISNODE | __GFP_NORETRY;
222	return alloc_pages_node(0, gfp_mask, order);
223}
224
225static void setup_quasi_va_is_pa(void)
226{
227	HV_PTE *pgtable;
228	HV_PTE pte;
229	int i;
230
231	/*
232	 * Flush our TLB to prevent conflicts between the previous contents
233	 * and the new stuff we're about to add.
234	 */
235	local_flush_tlb_all();
236
237	/* setup VA is PA, at least up to PAGE_OFFSET */
238
239	pgtable = (HV_PTE *)current->mm->pgd;
240	pte = hv_pte(_PAGE_KERNEL | _PAGE_HUGE_PAGE);
241	pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3);
242
243	for (i = 0; i < pgd_index(PAGE_OFFSET); i++) {
244		unsigned long pfn = i << (HPAGE_SHIFT - PAGE_SHIFT);
245		if (pfn_valid(pfn))
246			__set_pte(&pgtable[i], pfn_pte(pfn, pte));
247	}
248}
249
250
251NORET_TYPE void machine_kexec(struct kimage *image)
252{
253	void *reboot_code_buffer;
254	NORET_TYPE void (*rnk)(unsigned long, void *, unsigned long)
255		ATTRIB_NORET;
256
257	/* Mask all interrupts before starting to reboot. */
258	interrupt_mask_set_mask(~0ULL);
259
260	kexec_find_and_set_command_line(image);
261
262	/*
263	 * Adjust the home caching of the control page to be cached on
264	 * this cpu, and copy the assembly helper into the control
265	 * code page, which we map in the vmalloc area.
266	 */
267	homecache_change_page_home(image->control_code_page, 0,
268				   smp_processor_id());
269	reboot_code_buffer = vmap(&image->control_code_page, 1, 0,
270				  __pgprot(_PAGE_KERNEL | _PAGE_EXECUTABLE));
271	memcpy(reboot_code_buffer, relocate_new_kernel,
272	       relocate_new_kernel_size);
273	__flush_icache_range(
274		(unsigned long) reboot_code_buffer,
275		(unsigned long) reboot_code_buffer + relocate_new_kernel_size);
276
277	setup_quasi_va_is_pa();
278
279	/* now call it */
280	rnk = reboot_code_buffer;
281	(*rnk)(image->head, reboot_code_buffer, image->start);
282}