X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Falpha-arch.c;h=066355f946eec8b3f1e91a9deb2cd2840920a502;hb=e48026257ea92807b2a5ee799476be198fc64dd6;hp=001bc18725e776193cf77b82fca67d81a02f82e9;hpb=8dc064d2296902f01afd9107e89a81146e3771fe;p=sbcl.git diff --git a/src/runtime/alpha-arch.c b/src/runtime/alpha-arch.c index 001bc18..066355f 100644 --- a/src/runtime/alpha-arch.c +++ b/src/runtime/alpha-arch.c @@ -136,7 +136,6 @@ unsigned long arch_install_breakpoint(void *pc) unsigned int *ptr = (unsigned int *)pc; unsigned long result = (unsigned long) *ptr; *ptr = BREAKPOINT_INST; - *(ptr+1)=trap_Breakpoint; os_flush_icache((os_vm_address_t)ptr, sizeof(unsigned long)); @@ -164,7 +163,6 @@ emulate_branch(os_context_t *context,unsigned long orig_inst) int op = orig_inst >> 26; int reg_a = (orig_inst >> 21) & 0x1f; int reg_b = (orig_inst >> 16) & 0x1f; - int fn = orig_inst & 0xffff; int disp = (orig_inst&(1<<20)) ? orig_inst | (-1 << 21) : orig_inst&0x1fffff; int next_pc = *os_context_pc_addr(context); int branch = 0; /* was NULL; */ @@ -231,70 +229,101 @@ emulate_branch(os_context_t *context,unsigned long orig_inst) static sigset_t orig_sigmask; +/* Perform the instruction that we overwrote with a breakpoint. As we + * don't have a single-step facility, this means we have to: + * - put the instruction back + * - put a second breakpoint at the following instruction, + * set after_breakpoint and continue execution. + * + * When the second breakpoint is hit (very shortly thereafter, we hope) + * sigtrap_handler gets called again, but follows the AfterBreakpoint + * arm, which + * - puts a bpt back in the first breakpoint place (running across a + * breakpoint shouldn't cause it to be uninstalled) + * - replaces the second bpt with the instruction it was meant to be + * - carries on + * + * Clear? + */ + void arch_do_displaced_inst(os_context_t *context,unsigned int orig_inst) { + /* Apparent off-by-one errors ahoy. If you consult the Alpha ARM, + * it will tell you that after a BPT, the saved PC is the address + * of the instruction _after_ the instruction that caused the trap. + * + * However, we decremented PC by 4 before calling the Lisp-level + * handler that calls this routine (see alpha-arch.c line 322 and + * friends) so when we get to this point PC is actually pointing + * at the BPT instruction itself. This is good, because this is + * where we want to restart execution when we do that */ + unsigned int *pc=(unsigned int *)(*os_context_pc_addr(context)); unsigned int *next_pc; - unsigned int next_inst; int op = orig_inst >> 26;; - fprintf(stderr,"arch_do_displaced_inst depends on sigreturn, which is not implemented and will\nalways fail\n"); + orig_sigmask = *os_context_sigmask_addr(context); sigaddset_blockable(os_context_sigmask_addr(context)); - /* Figure out where the displaced inst is going. */ - if(op == 0x1a || (op&0xf) == 0x30) /* branch...ugh */ - /* The cast to long is just to shut gcc up. */ - next_pc = (unsigned int *)((long)emulate_branch(context,orig_inst)); - else - next_pc = pc+1; - /* Put the original instruction back. */ *pc = orig_inst; os_flush_icache((os_vm_address_t)pc, sizeof(unsigned long)); skipped_break_addr = pc; + /* Figure out where we will end up after running the displaced + * instruction */ + if(op == 0x1a || (op&0xf) == 0x30) /* a branch */ + /* The cast to long is just to shut gcc up. */ + next_pc = (unsigned int *)((long)emulate_branch(context,orig_inst)); + else + next_pc = pc+1; + /* Set the after breakpoint. */ displaced_after_inst = *next_pc; *next_pc = BREAKPOINT_INST; after_breakpoint=1; os_flush_icache((os_vm_address_t)next_pc, sizeof(unsigned long)); - - monitor_or_something(); - sigreturn(context); -} - -#define AfterBreakpoint 100 - -static void -sigill_handler(int signal, siginfo_t *siginfo, os_context_t *context) { - fake_foreign_function_call(context); - monitor_or_something(); } static void sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context) { + unsigned int code; + /* Don't disallow recursive breakpoint traps. Otherwise, we can't */ /* use debugger breakpoints anywhere in here. */ - sigset_t *mask=(os_context_sigmask_addr(context)); - unsigned int code; - fprintf(stderr,"sigtrap_handler:signal %d context=%p ",signal,context); sigsetmask(mask); - /* this is different from how CMUCL does it. CMUCL used - * "call_pal PAL_gentrap", which doesn't do anything on Linux - * so screwed up our offsets in odd ways. We use "bpt" instead - */ - - /* probably we should - assert(*(unsigned int*)(*os_context_pc_addr(context)-4) == BREAKPOINT_INST) - but I've not decided a good way to handle it if it turns out not to be - */ + /* this is different from how CMUCL does it. CMUCL used "call_pal + * PAL_gentrap", which doesn't do anything on Linux (unless NL0 + * contains certain specific values). We use "bugchk" instead. + * It's (for our purposes) just the same as bpt but has a + * different opcode so we can test whether we're dealing with a + * breakpoint or a "system service" */ + + if((*(unsigned int*)(*os_context_pc_addr(context)-4))== BREAKPOINT_INST) { + if(after_breakpoint) { + /* see comments above arch_do_displaced_inst. This is where + * we reinsert the breakpoint that we removed earlier */ + + *os_context_pc_addr(context) -=4; + *skipped_break_addr = BREAKPOINT_INST; + os_flush_icache((os_vm_address_t)skipped_break_addr, + sizeof(unsigned long)); + skipped_break_addr = NULL; + *(unsigned int *)*os_context_pc_addr(context) = + displaced_after_inst; + os_flush_icache((os_vm_address_t)*os_context_pc_addr(context), sizeof(unsigned long)); + *os_context_sigmask_addr(context)= orig_sigmask; + after_breakpoint=0; /* false */ + return; + } else + code = trap_Breakpoint; + } else + /* a "system service" */ code=*((u32 *)(*os_context_pc_addr(context))); - fprintf(stderr,"pc=%lx code=%d, inst=%x\n", - *os_context_pc_addr(context), code, - *(unsigned int*)(*os_context_pc_addr(context)-4)); + switch (code) { case trap_PendingInterrupt: arch_skip_instruction(context); @@ -310,43 +339,33 @@ sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context) interrupt_internal_error(signal, siginfo, context, code==trap_Cerror); break; - case trap_Breakpoint: + case trap_Breakpoint: /* call lisp-level handler */ *os_context_pc_addr(context) -=4; handle_breakpoint(signal, siginfo, context); break; case trap_FunctionEndBreakpoint: *os_context_pc_addr(context) -=4; - *os_context_pc_addr(context) = (int)handle_function_end_breakpoint(signal, siginfo, context); - break; - - case AfterBreakpoint: - *os_context_pc_addr(context) -=4; - *skipped_break_addr = BREAKPOINT_INST; - os_flush_icache((os_vm_address_t)skipped_break_addr, - sizeof(unsigned long)); - skipped_break_addr = NULL; - *(unsigned int *)*os_context_pc_addr(context) = displaced_after_inst; - os_flush_icache((os_vm_address_t)*os_context_pc_addr(context), sizeof(unsigned long)); - *os_context_sigmask_addr(context)= orig_sigmask; - after_breakpoint=0; /* NULL; */ + *os_context_pc_addr(context) = + (int)handle_function_end_breakpoint(signal, siginfo, context); break; default: + fprintf(stderr, "unidetified breakpoint/trap %d\n",code); interrupt_handle_now(signal, siginfo, context); break; } } -#define FIXNUM_VALUE(lispobj) (((int)lispobj)>>2) - static void sigfpe_handler(int signal, int code, os_context_t *context) { + /* what should this contain? interesting question. If it really + * is empty, why don't we just ignore the signal? -dan 2001.08.10 + */ } void arch_install_interrupt_handlers() { - undoably_install_low_level_interrupt_handler(SIGILL, sigill_handler); undoably_install_low_level_interrupt_handler(SIGTRAP, sigtrap_handler); undoably_install_low_level_interrupt_handler(SIGFPE, sigfpe_handler); } @@ -393,12 +412,3 @@ lispobj funcall3(lispobj function, lispobj arg0, lispobj arg1, lispobj arg2) return call_into_lisp(function, args, 3); } - -/* This is apparently called by emulate_branch, but isn't defined. So */ -/* just do nothing and hope it works... */ -void cacheflush(void) -{ - /* hoping probably isn't _actually_ enough. we should call_pal imb, - according to the arch ref manual - */ -}