/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) Hewlett-Packard (Paul Bame) paul_bame@hp.com */ #include <stdio.h> #define GET_REG(reg) ({ \ unsigned long r; \ __asm__ __volatile__( \ "copy " #reg ",%0" : "=r" (r) \ ); \ r; \ }) #define GET_SP() GET_REG(30) #define GET_RP() GET_REG(2) #define GET_PC() ({ \ unsigned long r; \ __asm__ __volatile__( \ "ldil L%%(.+8), %0\n\t" \ "ldo R%%(.+4)(%0), %0" : "=r" (r) \ ); \ r; \ }) /* These two would be MUCH easier with a quick asm() instruction! */ /* extract some bits, least-sig bit is numbered 0, unsigned */ #define GETBITSLSB0(i, start, length) \ (((i) >> (start)) & ((1 << (length)) - 1)) /* extract some bits, least-sig bit is numbered 0, signed */ #define GETBITSLSB0S(i, start, length) \ (((signed)((i) << (32 - (start + length)))) >> (32 - length)) /* bl xxx,%r2 */ #define BL2_BITS 0xe8400000 #define BL2_MASK 0xffe0e000 #define IS_BL2(i) (((i) & BL2_MASK) == BL2_BITS) /********** Not finished ************/ #define BLR_BITS 0xe8004 #define BLR_MASK 0xfc00e union bl { unsigned instr; struct { unsigned opcode:6; unsigned t:5; unsigned w1:5; unsigned dummy:3; unsigned w2_0_9:10; unsigned w2_10:1; unsigned n:1; unsigned w:1; } bits; }; static int assemble_17(unsigned instr) { union bl bl; int x; int sx; bl.instr = instr; x = bl.bits.w2_0_9; x |= bl.bits.w2_10 << 10; x |= bl.bits.w1 << 11; x |= bl.bits.w << (5 + 11); sx = x << (32 - 17); sx >>= (32 - 17 - 2); #if 0 printf("op %x t %x w1 %x w20 %x n %x w %x x %x 4x %x sx %d\n", bl.bits.opcode, bl.bits.t, bl.bits.w1, bl.bits.w2_0_9, bl.bits.n, bl.bits.w, x, x << 2, sx); #endif return sx; } static unsigned * find_rp(unsigned *sp, unsigned *dot, unsigned **btargetp) { unsigned *lim = sp - 1024; extern unsigned _etext, __text_start; while(sp > lim) { unsigned *maybe_rp = (unsigned *)*sp; if (0) printf("%p: %p\n", sp, maybe_rp); if (((unsigned)maybe_rp & 0x3) == 0x3 && maybe_rp < &_etext && maybe_rp >= &__text_start) { unsigned instr; unsigned *btarget; maybe_rp = (unsigned *)((unsigned)maybe_rp & ~0x3); /* check if instr - 2 is a bl ..., %r2 */ instr = maybe_rp[-2]; if (IS_BL2(instr)) { btarget = (unsigned *)((unsigned)maybe_rp + assemble_17(instr)); printf("%p: %p: bl %p, %%r2\n", sp, maybe_rp - 2, btarget ); if (btarget > dot) { printf("unlikely bl, .+0x%x\n", (unsigned)btarget - (unsigned)maybe_rp); } else { *btargetp = btarget; return sp; } } } sp--; } return 0; } void unwind() { unsigned *rp = (unsigned *)(GET_RP() & ~0x3); unsigned *sp = (unsigned *)GET_SP(); /* lie about these data types... _end could be 1-byte aligned */ extern unsigned _end; extern unsigned _etext; extern unsigned __text_start; unsigned *lastrpsp = sp; extern unsigned dotlabel; unsigned *dot; unsigned *our_entry; unsigned *lim; unsigned *btarget; asm("\ndotlabel:"); dot = &dotlabel; printf("Initial rp: %p\tsp: %p\tetext: %p\t.: %p\n", rp, sp, &_etext, dot); /* find where my RP is stored, hence my caller's stack frame */ for ( ; *sp != rp; sp--) { } printf("Found my RP on stack at %p\n", sp); /* stack frames are 16 words minimum, rp is stored in word -5 relative */ /* to stack pointer on entry to a routine, so we can calculate the sp */ /* on entry to the current routine */ sp += 5; printf("My entry SP was %p\n", sp); /* by disassembling the target of the branch which brought us here, */ /* we can learn our entry point address */ our_entry = (unsigned *)(assemble_17(rp[-2]) + (unsigned)rp); printf("Entry point to this routine is %p\n", our_entry); /* can't be sure about args, but some may be on stack... */ printf("%p: %p(%08x, %08x, %08x, %08x)\n", rp - 2, our_entry, sp[-9], sp[-10], sp[-11], sp[-12]); /* become the previous procedure */ dot = rp; /* this is the minimum stack frame size -- skip over it */ sp -= 16; sp = find_rp(sp, dot, &btarget); if (sp != 0) { rp = (unsigned *)((unsigned)*sp & ~0x3); printf("Found my RP (%p) on stack at %p\n", rp, sp); /* stack frames are 16 words minimum, rp is stored in word -5 relative */ /* to stack pointer on entry to a routine, so we can calculate the sp */ /* on entry to the current routine */ sp += 5; printf("My entry SP was %p\n", sp); /* by disassembling the target of the branch which brought us here, */ /* we can learn our entry point address */ if (0) our_entry = (unsigned *)(assemble_17(rp[-2]) + (unsigned)rp); printf("Entry point to this routine is %p\n", btarget); /* can't be sure about args, but some may be on stack... */ printf("%p: %p()\n", rp - 2, our_entry); /* become the previous procedure */ dot = rp; } } #if 0 void ounwind() { unsigned *sp = (unsigned *)GET_SP(); unsigned *rp = (unsigned *)GET_RP(); /* lie about these data types... _end could be 1-byte aligned */ extern unsigned _end; extern unsigned _etext; extern unsigned __text_start; unsigned *lim = sp - 1024*4; unsigned *lastrpsp = sp; extern unsigned dotlabel; unsigned *dot; asm("\ndotlabel:"); dot = &dotlabel; printf("Initial rp: %p\tsp: %p\tetext: %p\t.: %p\n", rp, sp, &_etext, dot); /* walk backwards in stack looking for likely RPs */ while(sp > lim) { unsigned *maybe_rp = (unsigned *)*sp; if (0) printf("%p: %p\n", sp, maybe_rp); if (((unsigned)maybe_rp & 0x3) == 0x3 && maybe_rp < &_etext && maybe_rp >= &__text_start) { unsigned instr; unsigned *btarget; maybe_rp = (unsigned *)((unsigned)maybe_rp & ~0x3); /* check if instr - 2 is a bl ..., %r2 */ instr = maybe_rp[-2]; if (IS_BL2(instr)) { btarget = (unsigned)maybe_rp + assemble_17(instr); printf("%p: %p: bl %p, %%r2, stack delta 0x%x\n", sp, maybe_rp - 2, btarget, (unsigned)lastrpsp - (unsigned)sp ); if (btarget > dot) { printf("unlikely bl, .+0x%x\n", (unsigned)btarget - (unsigned)maybe_rp); } lastrpsp = sp; } } sp--; } exit(77); } #endif

Generated by Doxygen 1.6.0 Back to index