kernel-ark/arch/tile/kernel/machine_kexec.c
Chris Metcalf 76c567fbba arch/tile: support 4KB page size as well as 64KB
The Tilera architecture traditionally supports 64KB page sizes
to improve TLB utilization and improve performance when the
hardware is being used primarily to run a single application.

For more generic server scenarios, it can be beneficial to run
with 4KB page sizes, so this commit allows that to be specified
(by modifying the arch/tile/include/hv/pagesize.h header).

As part of this change, we also re-worked the PTE management
slightly so that PTE writes all go through a __set_pte() function
where we can do some additional validation.  The set_pte_order()
function was eliminated since the "order" argument wasn't being used.

One bug uncovered was in the PCI DMA code, which wasn't properly
flushing the specified range.  This was benign with 64KB pages,
but with 4KB pages we were getting some larger flushes wrong.

The per-cpu memory reservation code also needed updating to
conform with the newer percpu stuff; before it always chose 64KB,
and that was always correct, but with 4KB granularity we now have
to pay closer attention and reserve the amount of memory that will
be requested when the percpu code starts allocating.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2011-03-10 13:17:53 -05:00

283 lines
7.1 KiB
C

/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* based on machine_kexec.c from other architectures in linux-2.6.18
*/
#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/elf.h>
#include <linux/highmem.h>
#include <linux/mmu_context.h>
#include <linux/io.h>
#include <linux/timex.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/checksum.h>
#include <hv/hypervisor.h>
/*
* This stuff is not in elf.h and is not in any other kernel include.
* This stuff is needed below in the little boot notes parser to
* extract the command line so we can pass it to the hypervisor.
*/
struct Elf32_Bhdr {
Elf32_Word b_signature;
Elf32_Word b_size;
Elf32_Half b_checksum;
Elf32_Half b_records;
};
#define ELF_BOOT_MAGIC 0x0E1FB007
#define EBN_COMMAND_LINE 0x00000004
#define roundupsz(X) (((X) + 3) & ~3)
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
void machine_shutdown(void)
{
/*
* Normally we would stop all the other processors here, but
* the check in machine_kexec_prepare below ensures we'll only
* get this far if we've been booted with "nosmp" on the
* command line or without CONFIG_SMP so there's nothing to do
* here (for now).
*/
}
void machine_crash_shutdown(struct pt_regs *regs)
{
/*
* Cannot happen. This type of kexec is disabled on this
* architecture (and enforced in machine_kexec_prepare below).
*/
}
int machine_kexec_prepare(struct kimage *image)
{
if (num_online_cpus() > 1) {
pr_warning("%s: detected attempt to kexec "
"with num_online_cpus() > 1\n",
__func__);
return -ENOSYS;
}
if (image->type != KEXEC_TYPE_DEFAULT) {
pr_warning("%s: detected attempt to kexec "
"with unsupported type: %d\n",
__func__,
image->type);
return -ENOSYS;
}
return 0;
}
void machine_kexec_cleanup(struct kimage *image)
{
/*
* We did nothing in machine_kexec_prepare,
* so we have nothing to do here.
*/
}
/*
* If we can find elf boot notes on this page, return the command
* line. Otherwise, silently return null. Somewhat kludgy, but no
* good way to do this without significantly rearchitecting the
* architecture-independent kexec code.
*/
static unsigned char *kexec_bn2cl(void *pg)
{
struct Elf32_Bhdr *bhdrp;
Elf32_Nhdr *nhdrp;
unsigned char *desc;
unsigned char *command_line;
__sum16 csum;
bhdrp = (struct Elf32_Bhdr *) pg;
/*
* This routine is invoked for every source page, so make
* sure to quietly ignore every impossible page.
*/
if (bhdrp->b_signature != ELF_BOOT_MAGIC ||
bhdrp->b_size > PAGE_SIZE)
return 0;
/*
* If we get a checksum mismatch, warn with the checksum
* so we can diagnose better.
*/
csum = ip_compute_csum(pg, bhdrp->b_size);
if (csum != 0) {
pr_warning("%s: bad checksum %#x (size %d)\n",
__func__, csum, bhdrp->b_size);
return 0;
}
nhdrp = (Elf32_Nhdr *) (bhdrp + 1);
while (nhdrp->n_type != EBN_COMMAND_LINE) {
desc = (unsigned char *) (nhdrp + 1);
desc += roundupsz(nhdrp->n_descsz);
nhdrp = (Elf32_Nhdr *) desc;
/* still in bounds? */
if ((unsigned char *) (nhdrp + 1) >
((unsigned char *) pg) + bhdrp->b_size) {
pr_info("%s: out of bounds\n", __func__);
return 0;
}
}
command_line = (unsigned char *) (nhdrp + 1);
desc = command_line;
while (*desc != '\0') {
desc++;
if (((unsigned long)desc & PAGE_MASK) != (unsigned long)pg) {
pr_info("%s: ran off end of page\n",
__func__);
return 0;
}
}
return command_line;
}
static void kexec_find_and_set_command_line(struct kimage *image)
{
kimage_entry_t *ptr, entry;
unsigned char *command_line = 0;
unsigned char *r;
HV_Errno hverr;
for (ptr = &image->head;
(entry = *ptr) && !(entry & IND_DONE);
ptr = (entry & IND_INDIRECTION) ?
phys_to_virt((entry & PAGE_MASK)) : ptr + 1) {
if ((entry & IND_SOURCE)) {
void *va =
kmap_atomic_pfn(entry >> PAGE_SHIFT);
r = kexec_bn2cl(va);
if (r) {
command_line = r;
break;
}
kunmap_atomic(va);
}
}
if (command_line != 0) {
pr_info("setting new command line to \"%s\"\n",
command_line);
hverr = hv_set_command_line(
(HV_VirtAddr) command_line, strlen(command_line));
kunmap_atomic(command_line);
} else {
pr_info("%s: no command line found; making empty\n",
__func__);
hverr = hv_set_command_line((HV_VirtAddr) command_line, 0);
}
if (hverr)
pr_warning("%s: hv_set_command_line returned error: %d\n",
__func__, hverr);
}
/*
* The kexec code range-checks all its PAs, so to avoid having it run
* amok and allocate memory and then sequester it from every other
* controller, we force it to come from controller zero. We also
* disable the oom-killer since if we do end up running out of memory,
* that almost certainly won't help.
*/
struct page *kimage_alloc_pages_arch(gfp_t gfp_mask, unsigned int order)
{
gfp_mask |= __GFP_THISNODE | __GFP_NORETRY;
return alloc_pages_node(0, gfp_mask, order);
}
static void setup_quasi_va_is_pa(void)
{
HV_PTE *pgtable;
HV_PTE pte;
int i;
/*
* Flush our TLB to prevent conflicts between the previous contents
* and the new stuff we're about to add.
*/
local_flush_tlb_all();
/* setup VA is PA, at least up to PAGE_OFFSET */
pgtable = (HV_PTE *)current->mm->pgd;
pte = hv_pte(_PAGE_KERNEL | _PAGE_HUGE_PAGE);
pte = hv_pte_set_mode(pte, HV_PTE_MODE_CACHE_NO_L3);
for (i = 0; i < pgd_index(PAGE_OFFSET); i++) {
unsigned long pfn = i << (HPAGE_SHIFT - PAGE_SHIFT);
if (pfn_valid(pfn))
__set_pte(&pgtable[i], pfn_pte(pfn, pte));
}
}
NORET_TYPE void machine_kexec(struct kimage *image)
{
void *reboot_code_buffer;
NORET_TYPE void (*rnk)(unsigned long, void *, unsigned long)
ATTRIB_NORET;
/* Mask all interrupts before starting to reboot. */
interrupt_mask_set_mask(~0ULL);
kexec_find_and_set_command_line(image);
/*
* Adjust the home caching of the control page to be cached on
* this cpu, and copy the assembly helper into the control
* code page, which we map in the vmalloc area.
*/
homecache_change_page_home(image->control_code_page, 0,
smp_processor_id());
reboot_code_buffer = vmap(&image->control_code_page, 1, 0,
__pgprot(_PAGE_KERNEL | _PAGE_EXECUTABLE));
memcpy(reboot_code_buffer, relocate_new_kernel,
relocate_new_kernel_size);
__flush_icache_range(
(unsigned long) reboot_code_buffer,
(unsigned long) reboot_code_buffer + relocate_new_kernel_size);
setup_quasi_va_is_pa();
/* now call it */
rnk = reboot_code_buffer;
(*rnk)(image->head, reboot_code_buffer, image->start);
}