[U-Boot-Users] Question About how the CPU find the right string address in U-boot binary file ?
Dear all, I study the U-boot.bin file using the objdump command, I don't know how the CPU can find the right string address when puts() string. For example, In my binary file, the string "Call backtrace: " in func "print_backtrace()" address is :0x0002b280, the func address is 0xfff03564, How the CPU can find the 0x0002b280 when call puts ("Call backtrace: "); ? I find the SMC serial driver "serial_putc()" but cannot know how to find the char address in binary file.
Below is the objdump result, can anyone explain to me ? thanks!
(PowerPC platform) void print_backtrace(unsigned long *sp) { int cnt = 0; unsigned long i;
puts ("Call backtrace: "); while (sp) { if ((uint)sp > END_OF_MEM) break;
i = sp[1]; if (cnt++ % 7 == 0) putc ('\n'); printf("%08lX ", i); if (cnt > 32) break; sp = (unsigned long *)*sp; } putc ('\n'); }
void show_regs(struct pt_regs * regs) { int i;
printf("NIP: %08lX XER: %08lX LR: %08lX REGS: %p TRAP: %04lx DAR: %08lX\n", regs->nip, regs->xer, regs->link, regs, regs->trap, regs->dar); printf("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n", regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0, regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0, regs->msr&MSR_IR ? 1 : 0, regs->msr&MSR_DR ? 1 : 0);
putc ('\n'); for (i = 0; i < 32; i++) { if ((i % 8) == 0) { printf("GPR%02d: ", i); }
printf("%08lX ", regs->gpr[i]); if ((i % 8) == 7) { putc ('\n'); } } }
void puts (const char *s) { DECLARE_GLOBAL_DATA_PTR;
#ifdef CONFIG_SILENT_CONSOLE if (gd->flags & GD_FLG_SILENT) return; #endif
if (gd->flags & GD_FLG_DEVINIT) { /* Send to the standard output */ fputs (stdout, s); } else { /* Send directly to the handler */ serial_puts (s); } }
void serial_putc(const char c) { volatile cbd_t *tbdf; volatile char *buf; volatile smc_uart_t *up; volatile immap_t *im = (immap_t *)CFG_IMMR;
if (c == '\n') serial_putc ('\r');
up = (smc_uart_t *)&(im->im_dprambase[PROFF_SMC]);
tbdf = (cbd_t *)&im->im_dprambase[up->smc_tbase];
/* Wait for last character to go. */ buf = (char *)tbdf->cbd_bufaddr; while (tbdf->cbd_sc & BD_SC_READY) ;
*buf = c; tbdf->cbd_datlen = 1; tbdf->cbd_sc |= BD_SC_READY; }
------------------------------------------------------------------------------------ hex code in u-boot.bin string: 0002b280h: 43 61 6C 6C 20 62 61 63 6B 74 72 61 63 65 3A 20 ; Call backtrace:
0002b290h: 00 00 00 00 25 30 38 6C 58 20 00 00 4E 49 50 3A ; ....%08lX ..NIP: 0002b2a0h: 20 25 30 38 6C 58 20 58 45 52 3A 20 25 30 38 6C ; %08lX XER: %08l 0002b2b0h: 58 20 4C 52 3A 20 25 30 38 6C 58 20 52 45 47 53 ; X LR: %08lX REGS 0002b2c0h: 3A 20 25 70 20 54 52 41 50 3A 20 25 30 34 6C 78 ; : %p TRAP: %04lx 0002b2d0h: 20 44 41 52 3A 20 25 30 38 6C 58 0A 00 00 00 00 ; DAR: %08lX..... 0002b2e0h: 4D 53 52 3A 20 25 30 38 6C 78 20 45 45 3A 20 25 ; MSR: %08lx EE: % 0002b2f0h: 30 31 78 20 50 52 3A 20 25 30 31 78 20 46 50 3A ; 01x PR: %01x FP: 0002b300h: 20 25 30 31 78 20 4D 45 3A 20 25 30 31 78 20 49 ; %01x ME: %01x I 0002b310h: 52 2F 44 52 3A 20 25 30 31 78 25 30 31 78 0A 00 ; R/DR: %01x%01x.. 0002b320h: 47 50 52 25 30 32 64 3A ; GPR%02d:
hex code in u-boot.bin func: print_backtrace() 00003584h: 94 21 FF D8 7C 08 02 A6 42 9F 00 05 BF 61 00 14 ; ?Ø|..¦B?.¿a.. 00003594h: 7F C8 02 A6 90 01 00 2C 80 1E FF F0 7C 7C 1B 78 ; ?¦..,€.ð||.x 000035a4h: 3B E0 00 00 7F C0 F2 14 80 7E 80 00 48 01 1B AD ; ;?.Àò.€~€.H..? 000035b4h: 2C 1C 00 00 41 82 00 70 3C 00 02 00 7C 1C 00 40 ; ,...A?p<...|..@ 000035c4h: 3D 20 92 49 61 29 24 93 7F EB FE 70 38 60 00 0A ; = 'Ia)$?ëþp8`.. 000035d4h: 41 81 00 54 7C 1F 48 96 83 7C 00 04 7C 00 FA 14 ; A?T|.H–ƒ|..|.? 000035e4h: 7C 00 16 70 7C 0B 00 50 1C 00 00 07 7C 00 F8 50 ; |..p|..P....|.øP 000035f4h: 2C 00 00 00 3B FF 00 01 40 A2 00 08 48 01 1B 21 ; ,...;..@?.H..! 00003604h: 80 7E 80 04 7F 64 DB 78 4C C6 31 82 48 01 1B 89 ; €~€.dÛxL?‚H..? 00003614h: 2C 1F 00 20 41 81 00 10 83 9C 00 00 2C 1C 00 00 ; ,.. A?.ƒœ..,... 00003624h: 40 82 FF 98 38 60 00 0A 48 01 1A F5 BB 61 00 14 ; @??`..H..õ»a.. 00003634h: 80 01 00 2C 38 21 00 28 7C 08 03 A6 4E 80 00 20 ; €..,8!.(|..¦N€. 00003644h: 00 03 89 F0 ; ..‰ð
show_regs() 00003648h: 94 21 FF E8 7C 08 02 A6 42 9F 00 05 BF 81 00 08 ; ?è|..¦B?.¿.. 00003658h: 7F C8 02 A6 90 01 00 1C 80 1E FF F0 7C 7F 1B 78 ; ?¦...€.ð|.x 00003668h: 80 9F 00 80 7F E7 FB 78 7F C0 F2 14 80 BF 00 94 ; €?€çûxÀò.€?? 00003678h: 80 7E 80 08 3B 80 00 00 80 DF 00 90 81 1F 00 A0 ; €~€.;€..€?..? 00003688h: 81 3F 00 A4 4C C6 31 82 48 01 1B 09 80 9F 00 84 ; ?.¤L?‚H...€?? 00003698h: 80 7E 80 0C 54 85 8F FE 54 86 97 FE 54 87 9F FE ; €~€.T…†—‡Ÿ? 000036a8h: 54 88 A7 FE 54 89 DF FE 54 8A E7 FE 4C C6 31 82 ; Tˆ§‰ßŠçþL?? 000036b8h: 48 01 1A E1 38 60 00 0A 48 01 1A 61 73 80 00 07 ; H..?`..H..as€.. 000036c8h: 7F 84 E3 78 40 A2 00 10 80 7E 80 10 4C C6 31 82 ; „ãx@ ?.€~€.L?? 000036d8h: 48 01 1A C1 57 80 10 3A 80 7E 80 04 7C 9F 00 2E ; H..ÁW€.:€~€.|?. 000036e8h: 4C C6 31 82 48 01 1A AD 38 60 00 0A 7F 80 1E 70 ; L?‚H..?`..€.p 000036f8h: 7C 00 01 94 54 00 18 38 7C 00 E0 50 2C 00 00 07 ; |.."T..8|.àP,... 00003708h: 3B 9C 00 01 40 A2 00 08 48 01 1A 11 2C 1C 00 1F ; ;?.@?.H...,... 00003718h: 40 81 FF AC 80 01 00 1C BB 81 00 08 38 21 00 18 ; @?¬€...»..8!.. 00003728h: 7C 08 03 A6 4E 80 00 20 00 03 89 04 ; |..¦N€. ..?
puts() 0001515ch: 94 21 FF E8 7C 08 02 A6 90 01 00 1C 7C 64 1B 78 ; ?è|..¦...|d.x 0001516ch: 80 1D 00 04 70 09 00 02 41 82 00 10 38 60 00 01 ; €...p...A?.8`.. 0001517ch: 4B FF FE 4D 48 00 00 08 48 00 FE 89 80 01 00 1C ; KþMH...H.€... 0001518ch: 38 21 00 18 7C 08 03 A6 4E 80 00 20 ; 8!..|..¦N€.
serial_putc() 00024f9ch: 2C 03 00 0A 94 21 FF E8 7C 08 02 A6 93 E1 00 10 ; ,...?è|..¦"?. 00024fach: 90 01 00 1C 7C 7F 1B 78 40 A2 00 0C 38 60 00 0D ; ?..|.x@?.8`.. 00024fbch: 4B FF FF E1 3D 20 F0 00 A1 29 00 02 3D 29 F0 00 ; K? ??..=)? 00024fcch: 81 69 00 04 A8 09 00 00 2C 00 00 00 41 80 FF F8 ; i..?..,...A€? 00024fdch: 38 00 00 01 9B EB 00 00 B0 09 00 02 A0 09 00 00 ; 8...›ë..?..?.. 00024fech: 83 E1 00 10 64 00 FF FF 60 00 80 00 B0 09 00 00 ; ƒá..d.`.€.?.. 00024ffch: 80 01 00 1C 38 21 00 18 7C 08 03 A6 4E 80 00 20 ; €...8!..|..¦N€.
------------------------------------------------------------------------------------- assemble code fff03564 <print_backtrace>: ---> length: C0, u-boot.bin address 0x00003584,offset address: 0xFFEFFFE0 fff03564: 94 21 ff d8 stwu r1,-40(r1) fff03568: 7c 08 02 a6 mflr r0 fff0356c: 42 9f 00 05 bcl- 20,4*cr7+so,fff03570 <print_backtrace+0xc> fff03570: bf 61 00 14 stmw r27,20(r1) fff03574: 7f c8 02 a6 mflr r30 fff03578: 90 01 00 2c stw r0,44(r1) fff0357c: 80 1e ff f0 lwz r0,-16(r30) fff03580: 7c 7c 1b 78 mr r28,r3 fff03584: 3b e0 00 00 li r31,0 fff03588: 7f c0 f2 14 add r30,r0,r30 fff0358c: 80 7e 80 00 lwz r3,-32768(r30) fff03590: 48 01 1b ad bl fff1513c <puts> fff03594: 2c 1c 00 00 cmpwi r28,0 fff03598: 41 82 00 70 beq- fff03608 <print_backtrace+0xa4> fff0359c: 3c 00 02 00 lis r0,512 fff035a0: 7c 1c 00 40 cmplw r28,r0 fff035a4: 3d 20 92 49 lis r9,-28087 fff035a8: 61 29 24 93 ori r9,r9,9363 fff035ac: 7f eb fe 70 srawi r11,r31,31 fff035b0: 38 60 00 0a li r3,10 fff035b4: 41 81 00 54 bgt- fff03608 <print_backtrace+0xa4> fff035b8: 7c 1f 48 96 mulhw r0,r31,r9 fff035bc: 83 7c 00 04 lwz r27,4(r28) fff035c0: 7c 00 fa 14 add r0,r0,r31 fff035c4: 7c 00 16 70 srawi r0,r0,2 fff035c8: 7c 0b 00 50 subf r0,r11,r0 fff035cc: 1c 00 00 07 mulli r0,r0,7 fff035d0: 7c 00 f8 50 subf r0,r0,r31 fff035d4: 2c 00 00 00 cmpwi r0,0 fff035d8: 3b ff 00 01 addi r31,r31,1 fff035dc: 40 a2 00 08 bne+ fff035e4 <print_backtrace+0x80> fff035e0: 48 01 1b 21 bl fff15100 <putc> fff035e4: 80 7e 80 04 lwz r3,-32764(r30) fff035e8: 7f 64 db 78 mr r4,r27 fff035ec: 4c c6 31 82 crclr 4*cr1+eq fff035f0: 48 01 1b 89 bl fff15178 <printf> fff035f4: 2c 1f 00 20 cmpwi r31,32 fff035f8: 41 81 00 10 bgt- fff03608 <print_backtrace+0xa4> fff035fc: 83 9c 00 00 lwz r28,0(r28) fff03600: 2c 1c 00 00 cmpwi r28,0 fff03604: 40 82 ff 98 bne+ fff0359c <print_backtrace+0x38> fff03608: 38 60 00 0a li r3,10 fff0360c: 48 01 1a f5 bl fff15100 <putc> fff03610: bb 61 00 14 lmw r27,20(r1) fff03614: 80 01 00 2c lwz r0,44(r1) fff03618: 38 21 00 28 addi r1,r1,40 fff0361c: 7c 08 03 a6 mtlr r0 fff03620: 4e 80 00 20 blr fff03624: 00 03 89 f0 .long 0x389f0
fff03628 <show_regs>: --->length 0xE8, u-boot.bin address 0x00003648,offset address: 0xFFEFFFE0 fff03628: 94 21 ff e8 stwu r1,-24(r1) fff0362c: 7c 08 02 a6 mflr r0 fff03630: 42 9f 00 05 bcl- 20,4*cr7+so,fff03634 <show_regs+0xc> fff03634: bf 81 00 08 stmw r28,8(r1) fff03638: 7f c8 02 a6 mflr r30 fff0363c: 90 01 00 1c stw r0,28(r1) fff03640: 80 1e ff f0 lwz r0,-16(r30) fff03644: 7c 7f 1b 78 mr r31,r3 fff03648: 80 9f 00 80 lwz r4,128(r31) fff0364c: 7f e7 fb 78 mr r7,r31 fff03650: 7f c0 f2 14 add r30,r0,r30 fff03654: 80 bf 00 94 lwz r5,148(r31) fff03658: 80 7e 80 08 lwz r3,-32760(r30) fff0365c: 3b 80 00 00 li r28,0 fff03660: 80 df 00 90 lwz r6,144(r31) fff03664: 81 1f 00 a0 lwz r8,160(r31) fff03668: 81 3f 00 a4 lwz r9,164(r31) fff0366c: 4c c6 31 82 crclr 4*cr1+eq fff03670: 48 01 1b 09 bl fff15178 <printf> fff03674: 80 9f 00 84 lwz r4,132(r31) fff03678: 80 7e 80 0c lwz r3,-32756(r30) fff0367c: 54 85 8f fe rlwinm r5,r4,17,31,31 fff03680: 54 86 97 fe rlwinm r6,r4,18,31,31 fff03684: 54 87 9f fe rlwinm r7,r4,19,31,31 fff03688: 54 88 a7 fe rlwinm r8,r4,20,31,31 fff0368c: 54 89 df fe rlwinm r9,r4,27,31,31 fff03690: 54 8a e7 fe rlwinm r10,r4,28,31,31 fff03694: 4c c6 31 82 crclr 4*cr1+eq fff03698: 48 01 1a e1 bl fff15178 <printf> fff0369c: 38 60 00 0a li r3,10 fff036a0: 48 01 1a 61 bl fff15100 <putc> fff036a4: 73 80 00 07 andi. r0,r28,7 fff036a8: 7f 84 e3 78 mr r4,r28 fff036ac: 40 a2 00 10 bne+ fff036bc <show_regs+0x94> fff036b0: 80 7e 80 10 lwz r3,-32752(r30) fff036b4: 4c c6 31 82 crclr 4*cr1+eq fff036b8: 48 01 1a c1 bl fff15178 <printf> fff036bc: 57 80 10 3a rlwinm r0,r28,2,0,29 fff036c0: 80 7e 80 04 lwz r3,-32764(r30) fff036c4: 7c 9f 00 2e lwzx r4,r31,r0 fff036c8: 4c c6 31 82 crclr 4*cr1+eq fff036cc: 48 01 1a ad bl fff15178 <printf> fff036d0: 38 60 00 0a li r3,10 fff036d4: 7f 80 1e 70 srawi r0,r28,3 fff036d8: 7c 00 01 94 addze r0,r0 fff036dc: 54 00 18 38 rlwinm r0,r0,3,0,28 fff036e0: 7c 00 e0 50 subf r0,r0,r28 fff036e4: 2c 00 00 07 cmpwi r0,7 fff036e8: 3b 9c 00 01 addi r28,r28,1 fff036ec: 40 a2 00 08 bne+ fff036f4 <show_regs+0xcc> fff036f0: 48 01 1a 11 bl fff15100 <putc> fff036f4: 2c 1c 00 1f cmpwi r28,31 fff036f8: 40 81 ff ac ble+ fff036a4 <show_regs+0x7c> fff036fc: 80 01 00 1c lwz r0,28(r1) fff03700: bb 81 00 08 lmw r28,8(r1) fff03704: 38 21 00 18 addi r1,r1,24 fff03708: 7c 08 03 a6 mtlr r0 fff0370c: 4e 80 00 20 blr fff03710: 00 03 89 04 .long 0x38904
fff1513c <puts>: ---> Length 0x38, u-boot.bin 0x0001515c, Offset address: 0xFFEFFFE0 fff1513c: 94 21 ff e8 stwu r1,-24(r1) fff15140: 7c 08 02 a6 mflr r0 fff15144: 90 01 00 1c stw r0,28(r1) fff15148: 7c 64 1b 78 mr r4,r3 fff1514c: 80 1d 00 04 lwz r0,4(r29) fff15150: 70 09 00 02 andi. r9,r0,2 fff15154: 41 82 00 10 beq- fff15164 <puts+0x28> fff15158: 38 60 00 01 li r3,1 fff1515c: 4b ff fe 4d bl fff14fa8 <fputs> fff15160: 48 00 00 08 b fff15168 <puts+0x2c> fff15164: 48 00 fe 89 bl fff24fec <serial_puts> fff15168: 80 01 00 1c lwz r0,28(r1) fff1516c: 38 21 00 18 addi r1,r1,24 fff15170: 7c 08 03 a6 mtlr r0 fff15174: 4e 80 00 20 blr
fff24f7c <serial_putc>: Length 0x6C fff24f7c: 2c 03 00 0a cmpwi r3,10 fff24f80: 94 21 ff e8 stwu r1,-24(r1) fff24f84: 7c 08 02 a6 mflr r0 fff24f88: 93 e1 00 10 stw r31,16(r1) fff24f8c: 90 01 00 1c stw r0,28(r1) fff24f90: 7c 7f 1b 78 mr r31,r3 fff24f94: 40 a2 00 0c bne+ fff24fa0 <serial_putc+0x24> fff24f98: 38 60 00 0d li r3,13 fff24f9c: 4b ff ff e1 bl fff24f7c <serial_putc> fff24fa0: 3d 20 f0 00 lis r9,-4096 fff24fa4: a1 29 00 02 lhz r9,2(r9) fff24fa8: 3d 29 f0 00 addis r9,r9,-4096 fff24fac: 81 69 00 04 lwz r11,4(r9) fff24fb0: a8 09 00 00 lha r0,0(r9) fff24fb4: 2c 00 00 00 cmpwi r0,0 fff24fb8: 41 80 ff f8 blt+ fff24fb0 <serial_putc+0x34> fff24fbc: 38 00 00 01 li r0,1 fff24fc0: 9b eb 00 00 stb r31,0(r11) fff24fc4: b0 09 00 02 sth r0,2(r9) fff24fc8: a0 09 00 00 lhz r0,0(r9) fff24fcc: 83 e1 00 10 lwz r31,16(r1) fff24fd0: 64 00 ff ff oris r0,r0,65535 fff24fd4: 60 00 80 00 ori r0,r0,32768 fff24fd8: b0 09 00 00 sth r0,0(r9) fff24fdc: 80 01 00 1c lwz r0,28(r1) fff24fe0: 38 21 00 18 addi r1,r1,24 fff24fe4: 7c 08 03 a6 mtlr r0 fff24fe8: 4e 80 00 20 blr
wang baohua wrote:
Dear all, I study the U-boot.bin file using the objdump command, I don't know how the CPU can find the right string address when puts() string. For example, In my binary file, the string "Call backtrace: " in func "print_backtrace()" address is :0x0002b280, the func address is 0xfff03564, How the CPU can find the 0x0002b280 when call puts ("Call backtrace: "); ? I find the SMC serial driver "serial_putc()" but cannot know how to find the char address in binary file.
Below is the objdump result, can anyone explain to me ? thanks!
Please don't post HTML, use plain text.
I don't understand your question, why are you asking it? Are you trying to figure out a problem or are you just trying to understand the linking processes?
Using objdump on u-boot.bin is not valid. U-boot.bin is a binary file, objdump works on ELF (linker formatted) files.
http://en.wikipedia.org/wiki/Executable_and_Linkable_Format
When you link the ELF files, the linker fixes up all the addresses so the linker sets the proper address in the instruction that the CPU ultimately executes. The u-boot.bin file is a raw binary dump of the result.
Was that your question???
Best regards, gvb
Sorry for my poor English. I want to clearly understand the linking processes,especially detail string loading process. In fact, I use objcopy to convert the u-boot.bin to u-boot.elf, then using objdump to process elf. (In my real enviroment, I only had the MIPS arch binary format, need to convert it first. ) "u-boot.bin file is a raw binary dump of the result". Can you detail tell me the how to find the right string address when call puts("") in a func ? Now I know the string in the .got section, but how to calc the loading address ? there need some address convert from the binary file, you see the string "Call backtrace:" address is 0x0002b280, func print_backtrace() address is 0x00003584(in objdump is 0xfff03564), module traps.o .got2 address is 0xfff34024. What's the relationship among them ?
I update the dump info, please see it.
-------------------------------------------------------------------------------------------------------------- u-boot.map
.reloc 0xfff34000 0x1578 *(.got) 0xfff34000 _GOT2_TABLE_ = . *(.got2) .got2 0xfff34000 0x24 cpu/mpc8260/start.o .got2 0xfff34024 0x4c cpu/mpc8260/libmpc8260.a(traps.o) ------------------------------------------------------------------------------------------------------------------ fff03564 <print_backtrace> fff03564: 94 21 ff d8 stwu r1,-40(r1) fff03568: 7c 08 02 a6 mflr r0 fff0356c: 42 9f 00 05 bcl- 20,4*cr7+so,fff03570 <print_backtrace+0xc> fff03570: bf 61 00 14 stmw r27,20(r1) fff03574: 7f c8 02 a6 mflr r30 fff03578: 90 01 00 2c stw r0,44(r1) fff0357c: 80 1e ff f0 lwz r0,-16(r30) fff03580: 7c 7c 1b 78 mr r28,r3 fff03584: 3b e0 00 00 li r31,0 fff03588: 7f c0 f2 14 add r30,r0,r30 fff0358c: 80 7e 80 00 lwz r3,-32768(r30) fff03590: 48 01 1b ad bl fff1513c <puts> fff03594: 2c 1c 00 00 cmpwi r28,0 fff03598: 41 82 00 70 beq- fff03608 <print_backtrace+0xa4> fff0359c: 3c 00 02 00 lis r0,512 fff035a0: 7c 1c 00 40 cmplw r28,r0 fff035a4: 3d 20 92 49 lis r9,-28087 fff035a8: 61 29 24 93 ori r9,r9,9363 fff035ac: 7f eb fe 70 srawi r11,r31,31 fff035b0: 38 60 00 0a li r3,10 fff035b4: 41 81 00 54 bgt- fff03608 <print_backtrace+0xa4> fff035b8: 7c 1f 48 96 mulhw r0,r31,r9 fff035bc: 83 7c 00 04 lwz r27,4(r28) fff035c0: 7c 00 fa 14 add r0,r0,r31 fff035c4: 7c 00 16 70 srawi r0,r0,2 fff035c8: 7c 0b 00 50 subf r0,r11,r0 fff035cc: 1c 00 00 07 mulli r0,r0,7 fff035d0: 7c 00 f8 50 subf r0,r0,r31 fff035d4: 2c 00 00 00 cmpwi r0,0 fff035d8: 3b ff 00 01 addi r31,r31,1 fff035dc: 40 a2 00 08 bne+ fff035e4 <print_backtrace+0x80> fff035e0: 48 01 1b 21 bl fff15100 <putc> fff035e4: 80 7e 80 04 lwz r3,-32764(r30) fff035e8: 7f 64 db 78 mr r4,r27 fff035ec: 4c c6 31 82 crclr 4*cr1+eq fff035f0: 48 01 1b 89 bl fff15178 <printf> fff035f4: 2c 1f 00 20 cmpwi r31,32 fff035f8: 41 81 00 10 bgt- fff03608 <print_backtrace+0xa4> fff035fc: 83 9c 00 00 lwz r28,0(r28) fff03600: 2c 1c 00 00 cmpwi r28,0 fff03604: 40 82 ff 98 bne+ fff0359c <print_backtrace+0x38> fff03608: 38 60 00 0a li r3,10 fff0360c: 48 01 1a f5 bl fff15100 <putc> fff03610: bb 61 00 14 lmw r27,20(r1) fff03614: 80 01 00 2c lwz r0,44(r1) fff03618: 38 21 00 28 addi r1,r1,40 fff0361c: 7c 08 03 a6 mtlr r0 fff03620: 4e 80 00 20 blr fff03624: 00 03 89 f0 .long 0x389f0 ------------------------------------------------------------------------------------------------------------------- u-boot.bin 0002b280h: 43 61 6C 6C 20 62 61 63 6B 74 72 61 63 65 3A 20 ; Call backtrace:
print_backtrace() 00003584h: 94 21 FF D8 7C 08 02 A6 42 9F 00 05 BF 61 00 14 ; ?貄..?.縜.. 00003594h: 7F C8 02 A6 90 01 00 2C 80 1E FF F0 7C 7C 1B 78 ; ?..,€.饇|.x 000035a4h: 3B E0 00 00 7F C0 F2 14 80 7E 80 00 48 01 1B AD ; ;?.莉.€~€.H..? 000035b4h: 2C 1C 00 00 41 82 00 70 3C 00 02 00 7C 1C 00 40 ; ,...A?p<...|..@ 000035c4h: 3D 20 92 49 61 29 24 93 7F EB FE 70 38 60 00 0A ; = 扞a)$?膻p8`.. 000035d4h: 41 81 00 54 7C 1F 48 96 83 7C 00 04 7C 00 FA 14 ; A?T|.H杻|..|.? 000035e4h: 7C 00 16 70 7C 0B 00 50 1C 00 00 07 7C 00 F8 50 ; |..p|..P....|.鳳 000035f4h: 2C 00 00 00 3B FF 00 01 40 A2 00 08 48 01 1B 21 ; ,...;..@?.H..! 00003604h: 80 7E 80 04 7F 64 DB 78 4C C6 31 82 48 01 1B 89 ; €~€.d踴L?侶..? 00003614h: 2C 1F 00 20 41 81 00 10 83 9C 00 00 2C 1C 00 00 ; ,.. A?.儨..,... 00003624h: 40 82 FF 98 38 60 00 0A 48 01 1A F5 BB 61 00 14 ; @??`..H..趸a.. 00003634h: 80 01 00 2C 38 21 00 28 7C 08 03 A6 4E 80 00 20 ; €..,8!.(|..€. 00003644h: 00 03 89 F0 ; ..夝
--------------------------------------------------------------------------------------------------------------------- cpu\mpc8260\traps.c void print_backtrace(unsigned long *sp) { int cnt = 0; unsigned long i;
puts ("Call backtrace: "); while (sp) { if ((uint)sp > END_OF_MEM) break;
i = sp[1]; if (cnt++ % 7 == 0) putc ('\n'); printf("%08lX ", i); if (cnt > 32) break; sp = (unsigned long *)*sp; } putc ('\n'); }
On Wed, Jun 4, 2008 at 8:49 PM, Jerry Van Baren gerald.vanbaren@ge.com wrote:
wang baohua wrote:
Dear all, I study the U-boot.bin file using the objdump command, I don't know how the CPU can find the right string address when puts() string. For example, In my binary file, the string "Call backtrace: " in func "print_backtrace()" address is :0x0002b280, the func address is 0xfff03564, How the CPU can find the 0x0002b280 when call puts ("Call backtrace: "); ? I find the SMC serial driver "serial_putc()" but cannot know how to find the char address in binary file. Below is the objdump result, can anyone explain to me ? thanks!
Please don't post HTML, use plain text.
I don't understand your question, why are you asking it? Are you trying
to
figure out a problem or are you just trying to understand the linking processes?
Using objdump on u-boot.bin is not valid. U-boot.bin is a binary file, objdump works on ELF (linker formatted) files.
http://en.wikipedia.org/wiki/Executable_and_Linkable_Format
When you link the ELF files, the linker fixes up all the addresses so the linker sets the proper address in the instruction that the CPU ultimately executes. The u-boot.bin file is a raw binary dump of the result.
Was that your question???
Best regards, gvb
On Wed, 2008-06-04 at 12:04 +0800, wang baohua wrote:
Dear all, I study the U-boot.bin file using the objdump command, I don't know how the CPU can find the right string address when puts() string. For example, In my binary file, the string "Call backtrace: " in func "print_backtrace()" address is :0x0002b280, the func address is 0xfff03564, How the CPU can find the 0x0002b280 when call puts ("Call backtrace: "); ? I find the SMC serial driver "serial_putc()" but cannot know how to find the char address in binary file.
it's not exactly clear what you ask but lets start from the beginning.
r3 is the register used by a function call that takes one argument. so puts() will print the string that is in this register when it is called.
for the caller to get the correct address into r3 is a bit more work. u-boot is for powerpc compiled to be relocatable so the actual address of the string will be put into one entry in the GOT table (.got2 section). The compiler will then generate code that reads out the address from this table and put it into r3.
In the code below you can se that at address fff0358c r3 is set to what is in entry 0 in the .got table. hint r30 points in the middle of the table and quite possible outside any memory you have this is since the register offset is singed value and we want to maximize the numbers of entries.
assemble code fff03564 <print_backtrace>: ---> length: C0, u-boot.bin address 0x00003584,offset address: 0xFFEFFFE0 fff03564: 94 21 ff d8 stwu r1,-40(r1) fff03568: 7c 08 02 a6 mflr r0 fff0356c: 42 9f 00 05 bcl- 20,4*cr7+so,fff03570 <print_backtrace+0xc> fff03570: bf 61 00 14 stmw r27,20(r1) fff03574: 7f c8 02 a6 mflr r30 fff03578: 90 01 00 2c stw r0,44(r1) fff0357c: 80 1e ff f0 lwz r0,-16(r30) fff03580: 7c 7c 1b 78 mr r28,r3 fff03584: 3b e0 00 00 li r31,0 fff03588: 7f c0 f2 14 add r30,r0,r30 fff0358c: 80 7e 80 00 lwz r3,-32768(r30) fff03590: 48 01 1b ad bl fff1513c <puts>
participants (3)
-
Jerry Van Baren -
Kenneth Johansson -
wang baohua