ref: 8188b4f4f0e07b6669e6ae3c6c1099af917eaab4
dir: /sys/src/9/kw/rebootcode.s/
/*
* sheevaplug reboot code
*
* R11 is used by the loader as a temporary, so avoid it.
*/
#include "arm.s"
/*
* Turn off MMU, then copy the new kernel to its correct location
* in physical memory. Then jump to the start of the kernel.
*/
/* main(PADDR(entry), PADDR(code), size); */
TEXT main(SB), 1, $-4
MOVW $setR12(SB), R12
MOVW R0, p1+0(FP) /* destination, passed in R0 */
/* copy in arguments from frame */
MOVW R0, R8 /* entry point */
MOVW p2+4(FP), R9 /* source */
MOVW n+8(FP), R10 /* byte count */
WAVE('R')
BL cachesoff(SB)
/* now back in 29- or 26-bit addressing, mainly for SB */
/* turn the MMU off */
WAVE('e')
MOVW $KSEGM, R7
MOVW $PHYSDRAM, R0
BL _r15warp(SB)
BIC R7, R12 /* SB */
BIC R7, R13 /* SP */
/* don't care about R14 */
WAVE('b')
BL mmuinvalidate(SB)
WAVE('o')
BL mmudisable(SB)
WAVE('o')
MOVW R9, R4 /* restore regs across function calls */
MOVW R10, R5
MOVW R8, R6
/* set up a new stack for local vars and memmove args */
MOVW R6, SP /* tiny trampoline stack */
SUB $(0x20 + 4), SP /* back up before a.out header */
MOVW R14, -48(SP) /* store return addr */
SUB $48, SP /* allocate stack frame */
MOVW R6, 44(SP) /* save dest/entry */
MOVW R5, 40(SP) /* save count */
WAVE('t')
MOVW R6, 0(SP)
MOVW R6, 4(SP) /* push dest */
MOVW R6, R0
MOVW R4, 8(SP) /* push src */
MOVW R5, 12(SP) /* push size */
BL memmove(SB)
MOVW 44(SP), R6 /* restore R6 (dest/entry) */
MOVW 40(SP), R5 /* restore R5 (count) */
WAVE('-')
/*
* flush caches
*/
BL cacheuwbinv(SB)
WAVE('>')
WAVE('\r');
WAVE('\n');
/*
* jump to kernel entry point. Note the true kernel entry point is
* the virtual address KZERO|R6, but this must wait until
* the MMU is enabled by the kernel in l.s
*/
ORR R6, R6 /* NOP: avoid link bug */
B (R6)
/*
* turn the caches off, double map 0 & KZERO, invalidate TLBs, revert to
* tiny addresses. upon return, it will be safe to turn off the mmu.
*/
TEXT cachesoff(SB), 1, $-4
MOVW $(PsrDirq|PsrDfiq|PsrMsvc), R0
MOVW R0, CPSR
MOVW $KADDR(0x100-4), R7 /* just before this code */
MOVW R14, (R7) /* save link */
BL cacheuwbinv(SB)
MRC CpSC, 0, R0, C(CpCONTROL), C(0)
BIC $(CpCwb|CpCicache|CpCdcache|CpCalign), R0
MCR CpSC, 0, R0, C(CpCONTROL), C(0)
BARRIERS
/* redo double map of 0, KZERO */
MOVW $(L1+L1X(PHYSDRAM)), R4 /* address of PTE for 0 */
MOVW $PTEDRAM, R2 /* PTE bits */
// MOVW $PTEIO, R2 /* PTE bits */
MOVW $PHYSDRAM, R3
MOVW $512, R5
_ptrdbl:
ORR R3, R2, R1 /* first identity-map 0 to 0, etc. */
MOVW R1, (R4)
ADD $4, R4 /* bump PTE address */
ADD $MiB, R3 /* bump pa */
SUB.S $1, R5
BNE _ptrdbl
BARRIERS
MOVW $0, R0
MCR CpSC, 0, R0, C(CpTLB), C(CpTLBinvd), CpTLBinv
MCR CpSC, 0, R0, C(CpTLB), C(CpTLBinvu), CpTLBinv
BARRIERS
/* back to 29- or 26-bit addressing, mainly for SB */
MRC CpSC, 0, R0, C(CpCONTROL), C(0)
BIC $(CpCd32|CpCi32), R0
MCR CpSC, 0, R0, C(CpCONTROL), C(0)
BARRIERS
MOVW $KADDR(0x100-4), R7 /* just before this code */
MOVW (R7), R14 /* restore link */
RET
TEXT _r15warp(SB), 1, $-4
BIC $KSEGM, R14
ORR R0, R14
RET
TEXT mmudisable(SB), 1, $-4
MRC CpSC, 0, R0, C(CpCONTROL), C(0)
BIC $(CpChv|CpCmmu|CpCdcache|CpCicache|CpCwb), R0
MCR CpSC, 0, R0, C(CpCONTROL), C(0)
BARRIERS
RET
TEXT mmuinvalidate(SB), 1, $-4 /* invalidate all */
MOVW $0, R0
MCR CpSC, 0, R0, C(CpTLB), C(CpTLBinvu), CpTLBinv
BARRIERS
RET
TEXT cacheuwbinv(SB), 1, $-4 /* D+I writeback+invalidate */
BARRIERS
MOVW CPSR, R3 /* splhi */
ORR $(PsrDirq), R3, R1
MOVW R1, CPSR
_uwbinv: /* D writeback+invalidate */
MRC CpSC, 0, PC, C(CpCACHE), C(CpCACHEwbi), CpCACHEtest
BNE _uwbinv
MOVW $0, R0 /* I invalidate */
MCR CpSC, 0, R0, C(CpCACHE), C(CpCACHEinvi), CpCACHEall
/* drain L1 write buffer, also drains L2 eviction buffer on sheeva */
BARRIERS
MCR CpSC, CpL2, R0, C(CpTESTCFG), C(CpTCl2flush), CpTCl2all
BARRIERS
MCR CpSC, CpL2, R0, C(CpTESTCFG), C(CpTCl2inv), CpTCl2all
BARRIERS
MOVW R3, CPSR /* splx */
RET