/*
* arch/powerpc/kernel/misc64.S
*
* This file contains miscellaneous low-level functions.
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
* Adapted for iSeries by Mike Corrigan (mikejc@us.ibm.com)
* PPC64 updates by Dave Engebretsen (engebret@us.ibm.com)
*
* 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; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/config.h>
#include <linux/sys.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/cache.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#include <asm/thread_info.h>
.text
/*
* Returns (address we are running at) - (address we were linked at)
* for use before the text and data are mapped to KERNELBASE.
*/
_GLOBAL(reloc_offset)
mflr r0
bl 1f
1: mflr r3
LOAD_REG_IMMEDIATE(r4,1b)
subf r3,r4,r3
mtlr r0
blr
/*
* add_reloc_offset(x) returns x + reloc_offset().
*/
_GLOBAL(add_reloc_offset)
mflr r0
bl 1f
1: mflr r5
LOAD_REG_IMMEDIATE(r4,1b)
subf r5,r4,r5
add r3,r3,r5
mtlr r0
blr
_GLOBAL(get_msr)
mfmsr r3
blr
_GLOBAL(get_dar)
mfdar r3
blr
_GLOBAL(get_srr0)
mfsrr0 r3
blr
_GLOBAL(get_srr1)
mfsrr1 r3
blr
_GLOBAL(get_sp)
mr r3,r1
blr
#ifdef CONFIG_IRQSTACKS
_GLOBAL(call_do_softirq)
mflr r0
std r0,16(r1)
stdu r1,THREAD_SIZE-112(r3)
mr r1,r3
bl .__do_softirq
ld r1,0(r1)
ld r0,16(r1)
mtlr r0
blr
_GLOBAL(call___do_IRQ)
mflr r0
std r0,16(r1)
stdu r1,THREAD_SIZE-112(r5)
mr r1,r5
bl .__do_IRQ
ld r1,0(r1)
ld r0,16(r1)
mtlr r0
blr
#endif /* CONFIG_IRQSTACKS */
/*
* To be called by C code which needs to do some operations with MMU
* disabled. Note that interrupts have to be disabled by the caller
* prior to calling us. The code called _MUST_ be in the RMO of course
* and part of the linear mapping as we don't attempt to translate the
* stack pointer at all. The function is called with the stack switched
* to this CPU emergency stack
*
* prototype is void *call_with_mmu_off(void *func, void *data);
*
* the called function is expected to be of the form
*
* void *called(void *data);
*/
_GLOBAL(call_with_mmu_off)
mflr r0 /* get link, save it on stackframe */
std r0,16(r1)
mr r1,r5 /* save old stack ptr */
ld r1,PACAEMERGSP(r13) /* get emerg. stack */
subi r1,r1,STACK_FRAME_OVERHEAD
std r0,16(r1) /* save link on emerg. stack */
std r5,0(r1) /* save old stack ptr in backchain */
ld r3,0(r3) /* get to real function ptr (assume same TOC) */
bl 2f /* we need LR to return, continue at label 2 */
ld r0,16(r1) /* we return here from the call, get LR and */
ld r1,0(r1) /* .. old stack ptr */
mtspr SPRN_SRR0,r0 /* and get back to virtual mode with these */
mfmsr r4
ori r4,r4,MSR_IR|MSR_DR
mtspr SPRN_SRR1,r4
rfid
2: mtspr SPRN_SRR0,r3 /* coming from above, enter real mode */
mr r3,r4 /* get parameter */
mfmsr r0
ori r0,r0,MSR_IR|MSR_DR
xori r0,r0,MSR_IR|MSR_DR
mtspr SPRN_SRR1,r0
rfid
.section ".toc","aw"
PPC64_CACHES:
.tc ppc64_caches[TC],ppc64_caches
.section ".text"
/*
* Write any modified data cache blocks out to memory
* and invalidate the corresponding instruction cache blocks.
*
* flush_icache_range(unsigned long start, unsigned long stop)
*
* flush all bytes from start through stop-1 inclusive
*/
_KPROBE(__flush_icache_range)
/*
* Flush the data cache to memory
*
* Different systems have different cache line sizes
* and in some cases i-cache and d-cache line sizes differ from
* each other.
*/
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1LINESIZE(r10)/* Get cache line size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGLINESIZE(r10) /* Get log-2 of cache line size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
1: dcbst 0,r6
add r6,r6,r7
bdnz 1b
sync
/* Now invalidate the instruction cache */
lwz r7,ICACHEL1LINESIZE(r10) /* Get Icache line size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5
lwz r9,ICACHEL1LOGLINESIZE(r10) /* Get log-2 of Icache line size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
2: icbi 0,r6
add r6,r6,r7
bdnz 2b
isync
blr
.previous .text
/*
* Like above, but only do the D-cache.
*
* flush_dcache_range(unsigned long start, unsigned long stop)
*
* flush all bytes from start to stop-1 inclusive
*/
_GLOBAL(flush_dcache_range)
/*
* Flush the data cache to memory
*
* Different systems have different cache line sizes
*/
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1LINESIZE(r10) /* Get dcache line size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGLINESIZE(r10) /* Get log-2 of dcache line size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
0: dcbst 0,r6
add r6,r6,r7
bdnz 0b
sync
blr
/*
* Like above, but works on non-mapped physical addresses.
* Use only for non-LPAR setups ! It also assumes real mode
* is cacheable. Used for flushing out the DART before using
* it as uncacheable memory
*
* flush_dcache_phys_range(unsigned long start, unsigned long stop)
*
* flush all bytes from start to stop-1 inclusive
*/
_GLOBAL(flush_dcache_phys_range)
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1LINESIZE(r10) /* Get dcache line size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGLINESIZE(r10) /* Get log-2 of dcache line size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mfmsr r5 /* Disable MMU Data Relocation */
ori r0,r5,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsr r0
sync
isync
mtctr r8
0: dcbst 0,r6
add r6,r6,r7
bdnz 0b
sync
isync
mtmsr r5 /* Re-enable MMU Data Relocation */
sync
isync
blr
_GLOBAL(flush_inval_dcache_range)
ld r10,PPC64_CACHES@toc(r2)
lwz r7,DCACHEL1LINESIZE(r10) /* Get dcache line size */
addi r5,r7,-1
andc r6,r3,r5 /* round low to line bdy */
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGLINESIZE(r10)/* Get log-2 of dcache line size */
srw. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
sync
isync
mtctr r8
0: dcbf 0,r6
add r6,r6,r7
bdnz 0b
sync
isync
blr
/*
* Flush a particular page from the data cache to RAM.
* Note: this is necessary because the instruction cache does *not*
* snoop from the data cache.
*
* void __flush_dcache_icache(void *page)
*/
_GLOBAL(__flush_dcache_icache)
/*
* Flush the data cache to memory
*
* Different systems have different cache line sizes
*/
/* Flush the dcache */
ld r7,PPC64_CACHES@toc(r2)
clrrdi r3,r3,PAGE_SHIFT /* Page align */
lwz r4,DCACHEL1LINESPERPAGE(r7) /* Get # dcache lines per page */
lwz r5,DCACHEL1LINESIZE(r7) /* Get dcache line size */
mr r6,r3
mtctr r4
0: dcbst 0,r6
add r6,r6,r5
bdnz 0b
sync
/* Now invalidate the icache */
lwz r4,ICACHEL1LINESPERPAGE(r7) /* Get # icache lines per page */
lwz r5,ICACHEL1LINESIZE(r7) /* Get icache line size */
mtctr r4
1: icbi 0,r3
add r3,r3,r5
bdnz 1b
isync
blr
/*
* I/O string operations
*
* insb(port, buf, len)
* outsb(port, buf, len)
* insw(port, buf, len)
* outsw(port, buf, len)
* insl(port, buf, len)
* outsl(port, buf, len)
* insw_ns(port, buf, len)
* outsw_ns(port, buf, len)
* insl_ns(port, buf, len)
* outsl_ns(port, buf, len)
*
* The *_ns versions don't do byte-swapping.
*/
_GLOBAL(_insb)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,1
blelr-
00: lbz r5,0(r3)
eieio
stbu r5,1(r4)
bdnz 00b
twi 0,r5,0
isync
blr
_GLOBAL(_outsb)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,1
blelr-
00: lbzu r5,1(r4)
stb r5,0(r3)
bdnz 00b
sync
blr
_GLOBAL(_insw)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,2
blelr-
00: lhbrx r5,0,r3
eieio
sthu r5,2(r4)
bdnz 00b
twi 0,r5,0
isync
blr
_GLOBAL(_outsw)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,2
blelr-
00: lhzu r5,2(r4)
sthbrx r5,0,r3
bdnz 00b
sync
blr
_GLOBAL(_insl)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,4
blelr-
00: lwbrx r5,0,r3
eieio
stwu r5,4(r4)
bdnz 00b
twi 0,r5,0
isync
blr
_GLOBAL(_outsl)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,4
blelr-
00: lwzu r5,4(r4)
stwbrx r5,0,r3
bdnz 00b
sync
blr
/* _GLOBAL(ide_insw) now in drivers/ide/ide-iops.c */
_GLOBAL(_insw_ns)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,2
blelr-
00: lhz r5,0(r3)
eieio
sthu r5,2(r4)
bdnz 00b
twi 0,r5,0
isync
blr
/* _GLOBAL(ide_outsw) now in drivers/ide/ide-iops.c */
_GLOBAL(_outsw_ns)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,2
blelr-
00: lhzu r5,2(r4)
sth r5,0(r3)
bdnz 00b
sync
blr
_GLOBAL(_insl_ns)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,4
blelr-
00: lwz r5,0(r3)
eieio
stwu r5,4(r4)
bdnz 00b
twi 0,r5,0
isync
blr
_GLOBAL(_outsl_ns)
cmpwi 0,r5,0
mtctr r5
subi r4,r4,4
blelr-
00: lwzu r5,4(r4)
stw r5,0(r3)
bdnz 00b
sync
blr
/*
* identify_cpu and calls setup_cpu
* In: r3 = base of the cpu_specs array
* r4 = address of cur_cpu_spec
* r5 = relocation offset
*/
_GLOBAL(identify_cpu)
mfpvr r7
1:
lwz r8,CPU_SPEC_PVR_MASK(r3)
and r8,r8,r7
lwz r9,CPU_SPEC_PVR_VALUE(r3)
cmplw 0,r9,r8
beq 1f
addi r3,r3,CPU_SPEC_ENTRY_SIZE
b 1b
1:
sub r0,r3,r5
std r0,0(r4)
ld r4,CPU_SPEC_SETUP(r3)
add r4,r4,r5
ld r4,0(r4)
add r4,r4,r5
mtctr r4
/* Calling convention for cpu setup is r3=offset, r4=cur_cpu_spec */
mr r4,r3
mr r3,r5
bctr
/*
* do_cpu_ftr_fixups - goes through the list of CPU feature fixups
* and writes nop's over sections of code that don't apply for this cpu.
* r3 = data offset (not changed)
*/
_GLOBAL(do_cpu_ftr_fixups)
/* Get CPU 0 features */
LOAD_REG_IMMEDIATE(r6,cur_cpu_spec)
sub r6,r6,r3
ld r4,0(r6)
sub r4,r4,r3
ld r4,CPU_SPEC_FEATURES(r4)
/* Get the fixup table */
LOAD_REG_IMMEDIATE(r6,__start___ftr_fixup)
sub r6,r6,r3
LOAD_REG_IMMEDIATE(r7,__stop___ftr_fixup)
sub r7,r7,r3
/* Do the fixup */
1: cmpld r6,r7
bgelr
addi r6,r6,32
ld r8,-32(r6) /* mask */
and r8,r8,r4
ld r9,-24(r6) /* value */
cmpld r8,r9
beq 1b
ld r8,-16(r6) /* section begin */
ld r9,-8(r6) /* section end */
subf. r9,r8,r9
beq 1b
/* write nops over the section of code */
/* todo: if large section, add a branch at the start of it */
srwi r9,r9,2
mtctr r9
sub r8,r8,r3
lis r0,0x60000000@h /* nop */
3: stw r0,0(r8)
andi. r10,r4,CPU_FTR_SPLIT_ID_CACHE@l
beq 2f
dcbst 0,r8 /* suboptimal, but simpler */
sync
icbi 0,r8
2: addi r8,r8,4
bdnz 3b
sync /* additional sync needed on g4 */
isync
b 1b
#if defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE)
/*
* Do an IO access in real mode
*/
_GLOBAL(real_readb)
mfmsr r7
ori r0,r7,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsrd r0
sync
isync
mfspr r6,SPRN_HID4
rldicl r5,r6,32,0
ori r5,r5,0x100
rldicl r5,r5,32,0
sync
mtspr SPRN_HID4,r5
isync
slbia
isync
lbz r3,0(r3)
sync
mtspr SPRN_HID4,r6
isync
slbia
isync
mtmsrd r7
sync
isync
blr
/*
* Do an IO access in real mode
*/
_GLOBAL(real_writeb)
mfmsr r7
ori r0,r7,MSR_DR
xori r0,r0,MSR_DR
sync
mtmsrd r0
sync
isync
mfspr r6,SPRN_HID4
rldicl r5,r6,32,0
ori r5,r5,0x100
rldicl r5,r5,32,0
sync
mtspr SPRN_HID4,r5
isync
slbia
isync
stb r3,0(r4)
sync
mtspr SPRN_HID4,r6
isync
slbia
isync
mtmsrd r7
sync
isync
blr
#endif /* defined(CONFIG_PPC_PMAC) || defined(CONFIG_PPC_MAPLE) */
/*
* SCOM access functions for 970 (FX only for now)
*
* unsigned long scom970_read(unsigned int address);
* void scom970_write(unsigned int address, unsigned long value);
*
* The address passed in is the 24 bits register address. This code
* is 970 specific and will not check the status bits, so you should
* know what you are doing.
*/
_GLOBAL(scom970_read)
/* interrupts off */
mfmsr r4
ori r0,r4,MSR_EE
xori r0,r0,MSR_EE
mtmsrd r0,1
/* rotate 24 bits SCOM address 8 bits left and mask out it's low 8 bits
* (including parity). On current CPUs they must be 0'd,
* and finally or in RW bit
*/
rlwinm r3,r3,8,0,15
ori r3,r3,0x8000
/* do the actual scom read */
sync
mtspr SPRN_SCOMC,r3
isync
mfspr r3,SPRN_SCOMD
isync
mfspr r0,SPRN_SCOMC
isync
/* XXX: fixup result on some buggy 970's (ouch ! we lost a bit, bah
* that's the best we can do). Not implemented yet as we don't use
* the scom on any of the bogus CPUs yet, but may have to be done
* ultimately
*/
/* restore interrupts */
mtmsrd r4,1
blr
_GLOBAL(scom970_write)
/* interrupts off */
mfmsr r5
ori r0,r5,MSR_EE
xori r0,r0,MSR_EE
mtmsrd r0,1
/* rotate 24 bits SCOM address 8 bits left and mask out it's low 8 bits
* (including parity). On current CPUs they must be 0'd.
*/
rlwinm r3,r3,8,0,15
sync
mtspr SPRN_SCOMD,r4 /* write data */
isync
mtspr SPRN_SCOMC,r3 /* write command */
isync
mfspr 3,SPRN_SCOMC
isync
/* restore interrupts */
mtmsrd r5,1
blr
/*
* Create a kernel thread
* kernel_thread(fn, arg, flags)
*/
_GLOBAL(kernel_thread)
std r29,-24(r1)
std r30,-16(r1)
stdu r1,-STACK_FRAME_OVERHEAD(r1)
mr r29,r3
mr r30,r4
ori r3,r5,CLONE_VM /* flags */
oris r3,r3,(CLONE_UNTRACED>>16)
li r4,0 /* new sp (unused) */
li r0,__NR_clone
sc
cmpdi 0,r3,0 /* parent or child? */
bne 1f /* return if parent */
li r0,0
stdu r0,-STACK_FRAME_OVERHEAD(r1)
ld r2,8(r29)
ld r29,0(r29)
mtlr r29 /* fn addr in lr */
mr r3,r30 /* load arg and call fn */
blrl
li r0,__NR_exit /* exit after child exits */
li r3,0
sc
1: addi r1,r1,STACK_FRAME_OVERHEAD
ld r29,-24(r1)
ld r30,-16(r1)
blr
/*
* disable_kernel_fp()
* Disable the FPU.
*/
_GLOBAL(disable_kernel_fp)
mfmsr r3
rldicl r0,r3,(63-MSR_FP_LG),1
rldicl r3,r0,(MSR_FP_LG+1),0
mtmsrd r3 /* disable use of fpu now */
isync
blr
#ifdef CONFIG_ALTIVEC
#if 0 /* this has no callers for now */
/*
* disable_kernel_altivec()
* Disable the VMX.
*/
_GLOBAL(disable_kernel_altivec)
mfmsr r3
rldicl r0,r3,(63-MSR_VEC_LG),1
rldicl r3,r0,(MSR_VEC_LG+1),0
mtmsrd r3 /* disable use of VMX now */
isync
blr
#endif /* 0 */
/*
* giveup_altivec(tsk)
* Disable VMX for the task given as the argument,
* and save the vector registers in its thread_struct.
* Enables the VMX for use in the kernel on return.
*/
_GLOBAL(giveup_altivec)
mfmsr r5
oris r5,r5,MSR_VEC@h
mtmsrd r5 /* enable use of VMX now */
isync
cmpdi 0,r3,0
beqlr- /* if no previous owner, done */
addi r3,r3,THREAD /* want THREAD of task */
ld r5,PT_REGS(r3)
cmpdi 0,r5,0
SAVE_32VRS(0,r4,r3)
mfvscr vr0
li r4,THREAD_VSCR
stvx vr0,r4,r3
beq 1f
ld r4,_MSR-STACK_FRAME_OVERHEAD(r5)
lis r3,MSR_VEC@h
andc r4,r4,r3 /* disable FP for previous task */
std r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
#ifndef CONFIG_SMP
li r5,0
ld r4,last_task_used_altivec@got(r2)
std r5,0(r4)
#endif /* CONFIG_SMP */
blr
#endif /* CONFIG_ALTIVEC */
_GLOBAL(__setup_cpu_power3)
blr
_GLOBAL(execve)
li r0,__NR_execve
sc
bnslr
neg r3,r3
blr
/* kexec_wait(phys_cpu)
*
* wait for the flag to change, indicating this kernel is going away but
* the slave code for the next one is at addresses 0 to 100.
*
* This is used by all slaves.
*
* Physical (hardware) cpu id should be in r3.
*/
_GLOBAL(kexec_wait)
bl 1f
1: mflr r5
addi r5,r5,kexec_flag-1b
99: HMT_LOW
#ifdef CONFIG_KEXEC /* use no memory without kexec */
lwz r4,0(r5)
cmpwi 0,r4,0
bnea 0x60
#endif
b 99b
/* this can be in text because we won't change it until we are
* running in real anyways
*/
kexec_flag:
.long 0
#ifdef CONFIG_KEXEC
/* kexec_smp_wait(void)
*
* call with interrupts off
* note: this is a terminal routine, it does not save lr
*
* get phys id from paca
* set paca id to -1 to say we got here
* switch to real mode
* join other cpus in kexec_wait(phys_id)
*/
_GLOBAL(kexec_smp_wait)
lhz r3,PACAHWCPUID(r13)
li r4,-1
sth r4,PACAHWCPUID(r13) /* let others know we left */
bl real_mode
b .kexec_wait
/*
* switch to real mode (turn mmu off)
* we use the early kernel trick that the hardware ignores bits
* 0 and 1 (big endian) of the effective address in real mode
*
* don't overwrite r3 here, it is live for kexec_wait above.
*/
real_mode: /* assume normal blr return */
1: li r9,MSR_RI
li r10,MSR_DR|MSR_IR
mflr r11 /* return address to SRR0 */
mfmsr r12
andc r9,r12,r9
andc r10,r12,r10
mtmsrd r9,1
mtspr SPRN_SRR1,r10
mtspr SPRN_SRR0,r11
rfid
/*
* kexec_sequence(newstack, start, image, control, clear_all())
*
* does the grungy work with stack switching and real mode switches
* also does simple calls to other code
*/
_GLOBAL(kexec_sequence)
mflr r0
std r0,16(r1)
/* switch stacks to newstack -- &kexec_stack.stack */
stdu r1,THREAD_SIZE-112(r3)
mr r1,r3
li r0,0
std r0,16(r1)
/* save regs for local vars on new stack.
* yes, we won't go back, but ...
*/
std r31,-8(r1)
std r30,-16(r1)
std r29,-24(r1)
std r28,-32(r1)
std r27,-40(r1)
std r26,-48(r1)
std r25,-56(r1)
stdu r1,-112-64(r1)
/* save args into preserved regs */
mr r31,r3 /* newstack (both) */
mr r30,r4 /* start (real) */
mr r29,r5 /* image (virt) */
mr r28,r6 /* control, unused */
mr r27,r7 /* clear_all() fn desc */
mr r26,r8 /* spare */
lhz r25,PACAHWCPUID(r13) /* get our phys cpu from paca */
/* disable interrupts, we are overwriting kernel data next */
mfmsr r3
rlwinm r3,r3,0,17,15
mtmsrd r3,1
/* copy dest pages, flush whole dest image */
mr r3,r29
bl .kexec_copy_flush /* (image) */
/* turn off mmu */
bl real_mode
/* clear out hardware hash page table and tlb */
ld r5,0(r27) /* deref function descriptor */
mtctr r5
bctrl /* ppc_md.hash_clear_all(void); */
/*
* kexec image calling is:
* the first 0x100 bytes of the entry point are copied to 0
*
* all slaves branch to slave = 0x60 (absolute)
* slave(phys_cpu_id);
*
* master goes to start = entry point
* start(phys_cpu_id, start, 0);
*
*
* a wrapper is needed to call existing kernels, here is an approximate
* description of one method:
*
* v2: (2.6.10)
* start will be near the boot_block (maybe 0x100 bytes before it?)
* it will have a 0x60, which will b to boot_block, where it will wait
* and 0 will store phys into struct boot-block and load r3 from there,
* copy kernel 0-0x100 and tell slaves to back down to 0x60 again
*
* v1: (2.6.9)
* boot block will have all cpus scanning device tree to see if they
* are the boot cpu ?????
* other device tree differences (prop sizes, va vs pa, etc)...
*/
/* copy 0x100 bytes starting at start to 0 */
li r3,0
mr r4,r30
li r5,0x100
li r6,0
bl .copy_and_flush /* (dest, src, copy limit, start offset) */
1: /* assume normal blr return */
/* release other cpus to the new kernel secondary start at 0x60 */
mflr r5
li r6,1
stw r6,kexec_flag-1b(5)
mr r3,r25 # my phys cpu
mr r4,r30 # start, aka phys mem offset
mtlr 4
li r5,0
blr /* image->start(physid, image->start, 0); */
#endif /* CONFIG_KEXEC */
