diff options
Diffstat (limited to 'c/src/lib/libbsp/powerpc/shared/start/preload.S')
| -rw-r--r-- | c/src/lib/libbsp/powerpc/shared/start/preload.S | 278 |
1 files changed, 0 insertions, 278 deletions
diff --git a/c/src/lib/libbsp/powerpc/shared/start/preload.S b/c/src/lib/libbsp/powerpc/shared/start/preload.S deleted file mode 100644 index d8b47dfd2d..0000000000 --- a/c/src/lib/libbsp/powerpc/shared/start/preload.S +++ /dev/null @@ -1,278 +0,0 @@ -/* - * Mini-loader for the SVGM BSP. - * - * Author: Till Straumann, 10/2001 <strauman@slac.stanford.edu> - * - * Some ideas are borrowed from the powerpc/shared/bootloader - * by - * Copyright (C) 1998, 1999 Gabriel Paubert, paubert@iram.es - * Copyright (C) 1999 Eric Valette. valette@crf.canon.fr - * - * The SMON firmware is unable to load the RTEMS image below - * 0x2000 (I believe their stack is growing below 0x1000). - * - * The code provided by this file is responsible for the performing - * the following steps: - * - * 1) Save commandline parameters to an area that is - * a) not covered by the downloaded image - * b) will not be overwritten by the moved image - * nor the final BSS segment (rtems clears BSS - * before saving the command line). - * 2) Move the entire image (including this very file) to - * its final location starting at 0x0000. - * It is important to note that _NO_STACK_ is available - * during this step. Also, there is probably no return to - * SMON because relocating RTEMS will destroy vital SMON - * data (such as its stack). - * 3) Flush the cache to make sure the relocated image is actually - * in memory. - * 4) setup RTEMS environment (initial register values), most - * notably an initial STACK. The initial stack may be small and - * is used by RTEMS only at a very early stage. - * A safe place for the stack seems to be the 00..0x7f area. - * NOTE: we should respect the MAILBOX area 0x80..0xff! - * 5) switch the MMU off (because that's what RTEMS is expecting - * it to be at startup). - * 6) fire up rtems... - * - * - * Calling convention: - * R1: SMON SP - * R3: command line string start - * R4: command line string end + 1 - * R5: where SMON put the image - * if R5 is 0, the preloader will use its entry point - * as the image starting address. - * See NOTE below. - * R6: end of the image (i.e. R6-R5 is the image length) - * if R6 is 0, _edata will be used as the image length - * See NOTE below. - * - * NOTE: if the symbol DONT_USE_R5_ENTRY is defined, - * R5/R6 are never used and the necessary parameters are - * determined at runtime (R5) / linkage (R6) [_edata] - * - * ASSUMPTIONS: - * The code RELIES on the assumption that the image will be - * moved DOWNWARDS in memory and that the this loader is - * prepended to the image, i.e. it is safe to do - * codemove(codemove,0,codemove_end - codemove); - * (*0)(codemove_end, codemove_end-codemove, __rtems_end-codemove_end); - * where codemove(from, to, nbytes) is defined as - * codemove(from, to, nbytes) { while (nbytes--) *(to++)=*(from++); } - * Implicit to these assumptions is the assumption that the destination - * address is cache block aligned. - * Furthermore, the byte count is assumed to be a multiple - * of four - * - */ -#if 0 -#include <rtems/score/powerpc.h> -#else -#ifndef PPC_CACHE_ALIGNMENT -#define PPC_CACHE_ALIGNMENT 32 -#endif -#endif - -#include <rtems/score/cpu.h> -#include <rtems/asm.h> - -/* Note that major modifications may be needed - * if DESTINATION_ADDR is not 0 - */ -#define KERNELBASE 0x0 -#define INITIAL_STACK 0x70 /* 16-byte aligned */ -#define CACHE_LINE_SIZE PPC_CACHE_ALIGNMENT /* autodetect doesn't work, see below */ -#define ASSUME_RTEMS_INSTALLS_VECTORS /* assume we need not load vectors */ -#define DONT_USE_R5_ENTRY /* always dynamically determine the address we're running from */ - - /* put this into its own section which we want to - * be loaded at the very beginning. We should probably - * not use more than 255 bytes. - */ - PUBLIC_VAR(__rtems_start) - PUBLIC_VAR(__rtems_entry_point) - PUBLIC_VAR(__rtems_end) - .section .entry_point_section,"awx",@progbits -preload: - /* find out where we are */ - bl here -here: - xor r0,r0,r0 - mtmsr r0 /* clear MSR to known state */ - mflr r5 - addi r5,r5,-(here-preload) - lis r27,_edata@h - ori r27,r27,_edata@l - - /* at this point the register contents are - * R3: command line start - * R4: R3 + command line length - * R5: address we are running from / loaded to - * R27: image end - */ - - /* save command line start */ - mr r6, r3 - /* save the command line parameters if they are to be overwritten */ - sub. r17, r4, r3 /* string length */ - ble leaveparms /* <=0 -> no parameters */ - /* copy has to be out of the way of the bss; therefore we must - * put the string out of the way of both, the current end of - * the image (without bss) AND the end of the loaded image - * (including bss): - * |......image.........| downloaded image - * |image_bss...........| loaded image with bss appended - * - * ^ safe place for string - * - * the alternative scenario looks like this: - * |..image.............| downloaded image - * |image_bss...........| loaded image with bss appended - * ^ safe place for string - */ - lis r18, __rtems_end+0x10000@h /* round up, save one instruction */ - add r16, r5, r27 /* image end + 1 */ - cmpw r16, r18 - bge ishighenough - mr r16,r18 /* __rtems_end is higher than the image end - * (without bss) - */ -ishighenough: - cmpw r16, r3 /* destination start > current string start ? */ - ble leaveparms /* string already after dst, leave it */ - /* copy string from the last byte downwards */ - add r6, r16, r17 /* last byte of destination + 1 */ - mtctr r17 -1: - lbzu r3, -1(r4) - stbu r3, -1(r6) - bdnz 1b -leaveparms: - add r7, r6, r17 /* destination + strlen */ - -#ifndef CACHE_LINE_SIZE - /* Oh well, SMON has inhibited the cache, so this - * nice routine doesn't work... - */ - /* figure out the cache line size */ - li r16, 0x80 - cmpw r5, r16 /* 'from' must be > 0x80 */ - blt panic - -1: /* store some arbitrary, nonzero stuff in 0..0x7c */ - stwu r16,-4(r16) - cmpwi r16,0 - bne 1b - dcbz 0,r16 /* zero out one cache line */ - subi r16,r16,4 -2: lwzu r0,4(r16) /* search for a non-zero word */ - cmpwi r0,0 - beq 2b - /* OK, r16 now hold the size of a cache line in bytes */ -#else - li r16,CACHE_LINE_SIZE -#endif - - lis r3,preload@h - ori r3,r3,preload@l - mr r4,r5 /* from-addr */ - li r5,_preload_size/* this is never > 16k */ - /* now move ourselves to the link address ('preload'). - * We set up the LR, so domove() 'returns' to the - * relocated copy - */ - lis r0,return_here@h - ori r0,r0,return_here@l - mtlr r0 - b domove /* move the preloader itself */ -return_here: - /* now we move the entire rest of the image */ -#ifdef ASSUME_RTEMS_INSTALLS_VECTORS - lis r3,__rtems_start@h - ori r3,r3,__rtems_start@l - lis r0,preload@h /* calculate/adjust from address */ - ori r0,r0,preload@l - sub r0,r3,r0 - add r4,r4,r0 - sub r5,r27,r3 -#else - add r3,r3,r5 /* add preloader size to destination */ - add r4,r4,r5 /* and source addresses */ - sub r5,r27,r5 /* length of the remaining rest */ -#endif - bl domove - /* OK, now everything should be in place. - * we are ready to start... - */ - - /* setup initial stack for rtems early boot */ - li r1,INITIAL_STACK - /* tag TOS with a NULL pointer (for stack trace) */ - li r0, 0 - stw r0, 0(r1) - /* disable the MMU and fire up rtems */ - mfmsr r0 - ori r0,r0,MSR_IR|MSR_DR|MSR_IP|MSR_ME - xori r0,r0,MSR_IR|MSR_DR - mtsrr1 r0 - lis r0,__rtems_entry_point@h - ori r0,r0,__rtems_entry_point@l - mtsrr0 r0 - /* R6: start of command line */ - /* R7: end of command line +1 */ - rfi - - /* domove(to, from, nbytes): - * - * move a R5 bytes from R4 to R3 and flush - * the caches for the destination memory - * region. R16 provides the cache line size. - * DESTROYS: R0, R17, R18, CTR, CR - */ -domove: - addi r0,r5,3 /* convert to word count */ - srwi. r0,r0,2 - beq 3f /* nothing to do */ - cmpw r3,r4 /* from == to ? */ - beq 3f - mtctr r0 - la r18,-4(r4) - la r17,-4(r3) -1: lwzu r0,4(r18) - stwu r0,4(r17) - bdnz 1b /* move data */ - /* now, we must flush the destination cache region */ -#ifndef CACHE_LINE_SIZE - cmpwi r16,0 - beq 3f /* nothing to do */ -#endif -#if defined(CACHE_LINE_SIZE) && CACHE_LINE_SIZE > 0 - add r17,r3,r5 /* target end pointer */ - subi r0,r16,1 - add r17,r17,r0 - andc r17,r17,r0 /* cache aligned target end pointer */ - mr r18,r3 -2: cmpw r18,r17 - dcbst 0,r18 /* write out data cache line */ - icbi 0,r18 /* invalidate corresponding i-cache line */ - add r18,r18,r16 - blt 2b - sync /* make sure data is written back */ - isync /* invalidate possibly preloaded instructions */ -#endif -3: - blr - -#if !defined(CACHE_LINE_SIZE) -panic: - li r10,0x63 - mfmsr r0 - ori r0,r0,MSR_IP - mtmsr r0 - sc -#endif - -/* DONT PUT ANY CODE BELOW HERE */ -_preload_size = . - preload |