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// SPDX-License-Identifier: GPL-2.0
/*
* arch/alpha/boot/bootp.c
*
* Copyright (C) 1997 Jay Estabrook
*
* This file is used for creating a bootp file for the Linux/AXP kernel
*
* based significantly on the arch/alpha/boot/main.c of Linus Torvalds
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <generated/utsrelease.h>
#include <linux/mm.h>
#include <asm/console.h>
#include <asm/hwrpb.h>
#include <asm/io.h>
#include <stdarg.h>
#include "ksize.h"
extern unsigned long switch_to_osf_pal(unsigned long nr,
struct pcb_struct *pcb_va, struct pcb_struct *pcb_pa,
unsigned long *vptb);
extern void move_stack(unsigned long new_stack);
struct hwrpb_struct *hwrpb = INIT_HWRPB;
static struct pcb_struct pcb_va[1];
/*
* Find a physical address of a virtual object..
*
* This is easy using the virtual page table address.
*/
static inline void *
find_pa(unsigned long *vptb, void *ptr)
{
unsigned long address = (unsigned long) ptr;
unsigned long result;
result = vptb[address >> 13];
result >>= 32;
result <<= 13;
result |= address & 0x1fff;
return (void *) result;
}
/*
* This function moves into OSF/1 pal-code, and has a temporary
* PCB for that. The kernel proper should replace this PCB with
* the real one as soon as possible.
*
* The page table muckery in here depends on the fact that the boot
* code has the L1 page table identity-map itself in the second PTE
* in the L1 page table. Thus the L1-page is virtually addressable
* itself (through three levels) at virtual address 0x200802000.
*/
#define VPTB ((unsigned long *) 0x200000000)
#define L1 ((unsigned long *) 0x200802000)
void
pal_init(void)
{
unsigned long i, rev;
struct percpu_struct * percpu;
struct pcb_struct * pcb_pa;
/* Create the dummy PCB. */
pcb_va->ksp = 0;
pcb_va->usp = 0;
pcb_va->ptbr = L1[1] >> 32;
pcb_va->asn = 0;
pcb_va->pcc = 0;
pcb_va->unique = 0;
pcb_va->flags = 1;
pcb_va->res1 = 0;
pcb_va->res2 = 0;
pcb_pa = find_pa(VPTB, pcb_va);
/*
* a0 = 2 (OSF)
* a1 = return address, but we give the asm the vaddr of the PCB
* a2 = physical addr of PCB
* a3 = new virtual page table pointer
* a4 = KSP (but the asm sets it)
*/
srm_printk("Switching to OSF PAL-code .. ");
i = switch_to_osf_pal(2, pcb_va, pcb_pa, VPTB);
if (i) {
srm_printk("failed, code %ld\n", i);
__halt();
}
percpu = (struct percpu_struct *)
(INIT_HWRPB->processor_offset + (unsigned long) INIT_HWRPB);
rev = percpu->pal_revision = percpu->palcode_avail[2];
srm_printk("Ok (rev %lx)\n", rev);
tbia(); /* do it directly in case we are SMP */
}
static inline void
load(unsigned long dst, unsigned long src, unsigned long count)
{
memcpy((void *)dst, (void *)src, count);
}
/*
* Start the kernel.
*/
static inline void
runkernel(void)
{
__asm__ __volatile__(
"bis %0,%0,$27\n\t"
"jmp ($27)"
: /* no outputs: it doesn't even return */
: "r" (START_ADDR));
}
extern char _end;
#define KERNEL_ORIGIN \
((((unsigned long)&_end) + 511) & ~511)
void
start_kernel(void)
{
/*
* Note that this crufty stuff with static and envval
* and envbuf is because:
*
* 1. Frequently, the stack is short, and we don't want to overrun;
* 2. Frequently the stack is where we are going to copy the kernel to;
* 3. A certain SRM console required the GET_ENV output to stack.
* ??? A comment in the aboot sources indicates that the GET_ENV
* destination must be quadword aligned. Might this explain the
* behaviour, rather than requiring output to the stack, which
* seems rather far-fetched.
*/
static long nbytes;
static char envval[256] __attribute__((aligned(8)));
static unsigned long initrd_start;
srm_printk("Linux/AXP bootp loader for Linux " UTS_RELEASE "\n");
if (INIT_HWRPB->pagesize != 8192) {
srm_printk("Expected 8kB pages, got %ldkB\n",
INIT_HWRPB->pagesize >> 10);
return;
}
if (INIT_HWRPB->vptb != (unsigned long) VPTB) {
srm_printk("Expected vptb at %p, got %p\n",
VPTB, (void *)INIT_HWRPB->vptb);
return;
}
pal_init();
/* The initrd must be page-aligned. See below for the
cause of the magic number 5. */
initrd_start = ((START_ADDR + 5*KERNEL_SIZE + PAGE_SIZE) |
(PAGE_SIZE-1)) + 1;
#ifdef INITRD_IMAGE_SIZE
srm_printk("Initrd positioned at %#lx\n", initrd_start);
#endif
/*
* Move the stack to a safe place to ensure it won't be
* overwritten by kernel image.
*/
move_stack(initrd_start - PAGE_SIZE);
nbytes = callback_getenv(ENV_BOOTED_OSFLAGS, envval, sizeof(envval));
if (nbytes < 0 || nbytes >= sizeof(envval)) {
nbytes = 0;
}
envval[nbytes] = '\0';
srm_printk("Loading the kernel...'%s'\n", envval);
/* NOTE: *no* callbacks or printouts from here on out!!! */
/* This is a hack, as some consoles seem to get virtual 20000000 (ie
* where the SRM console puts the kernel bootp image) memory
* overlapping physical memory where the kernel wants to be put,
* which causes real problems when attempting to copy the former to
* the latter... :-(
*
* So, we first move the kernel virtual-to-physical way above where
* we physically want the kernel to end up, then copy it from there
* to its final resting place... ;-}
*
* Sigh... */
#ifdef INITRD_IMAGE_SIZE
load(initrd_start, KERNEL_ORIGIN+KERNEL_SIZE, INITRD_IMAGE_SIZE);
#endif
load(START_ADDR+(4*KERNEL_SIZE), KERNEL_ORIGIN, KERNEL_SIZE);
load(START_ADDR, START_ADDR+(4*KERNEL_SIZE), KERNEL_SIZE);
memset((char*)ZERO_PGE, 0, PAGE_SIZE);
strcpy((char*)ZERO_PGE, envval);
#ifdef INITRD_IMAGE_SIZE
((long *)(ZERO_PGE+256))[0] = initrd_start;
((long *)(ZERO_PGE+256))[1] = INITRD_IMAGE_SIZE;
#endif
runkernel();
}
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