/* * This software is part of the SBCL system. See the README file for * more information. * * This software is derived from the CMU CL system, which was * written at Carnegie Mellon University and released into the * public domain. The software is in the public domain and is * provided with absolutely no warranty. See the COPYING and CREDITS * files for more information. */ /* Note that although superficially it appears that we use * os_context_t like we ought to, we actually just assume its a * ucontext in places. Naughty */ #include #include #include "sbcl.h" #include "runtime.h" #include "globals.h" #include "validate.h" #include "os.h" #include "arch.h" #include "lispregs.h" #include "signal.h" #include "alloc.h" #include "interrupt.h" #include "interr.h" #include "breakpoint.h" extern char call_into_lisp_LRA[], call_into_lisp_end[]; extern size_t os_vm_page_size; #define BREAKPOINT_INST 0x80 void arch_init(void) { /* This must be called _after_ os_init(), so that we know what the * page size is. */ if (mmap((os_vm_address_t) call_into_lisp_LRA_page,os_vm_page_size, OS_VM_PROT_ALL,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,-1,0) == (os_vm_address_t) -1) perror("mmap"); /* call_into_lisp_LRA is a collection of trampolines written in asm - * see alpha-assem.S. We copy it to call_into_lisp_LRA_page where * VOPs and things can find it. (I don't know why they can't find it * where it was to start with.) */ bcopy(call_into_lisp_LRA,(void *)call_into_lisp_LRA_page,os_vm_page_size); os_flush_icache((os_vm_address_t)call_into_lisp_LRA_page, os_vm_page_size); return; } os_vm_address_t arch_get_bad_addr (int sig, siginfo_t *code, os_context_t *context) { unsigned int badinst; /* Instructions are 32 bit quantities. */ unsigned int *pc ; /* fprintf(stderr,"arch_get_bad_addr %d %p %p\n", sig, code, context); */ pc= (unsigned int *)(*os_context_pc_addr(context)); if (((unsigned long)pc) & 3) { return NULL; /* In what case would pc be unaligned?? */ } if ( (pc < READ_ONLY_SPACE_START || pc >= READ_ONLY_SPACE_START+READ_ONLY_SPACE_SIZE) && (pc < current_dynamic_space || pc >= current_dynamic_space + dynamic_space_size)) return NULL; return context->uc_mcontext.sc_traparg_a0; } void arch_skip_instruction(os_context_t *context) { /* This may be complete rubbish, as (at least for traps) pc points * _after_ the instruction that caused us to be here anyway. */ ((char*)*os_context_pc_addr(context)) +=4; } unsigned char * arch_internal_error_arguments(os_context_t *context) { return (unsigned char *)(*os_context_pc_addr(context)+4); } boolean arch_pseudo_atomic_atomic(os_context_t *context) { /* FIXME: this foreign_function_call_active test is dubious at * best. If a foreign call is made in a pseudo atomic section * (?) or more likely a pseudo atomic section is in a foreign * call then an interrupt is executed immediately. Maybe it * has to do with C code not maintaining pseudo atomic * properly. MG - 2005-08-10 * * The foreign_function_call_active used to live at each call-site * to arch_pseudo_atomic_atomic, but this seems clearer. * --NS 2007-05-15 */ return (!foreign_function_call_active) && ((*os_context_register_addr(context,reg_ALLOC)) & 1); } void arch_set_pseudo_atomic_interrupted(os_context_t *context) { /* On coming out of an atomic section, we subtract 1 from * reg_Alloc, then try to store something at that address. So, * to signal that it was interrupted and a signal should be handled, * we set bit 63 of reg_ALLOC here so that the end-of-atomic code * will raise SIGSEGV (no ram mapped there). We catch the signal * (see the appropriate *-os.c) and call interrupt_handle_pending() * for the saved signal instead */ *os_context_register_addr(context,reg_ALLOC) |= (1L<<63); } void arch_clear_pseudo_atomic_interrupted(os_context_t *context) { *os_context_register_addr(context, reg_ALLOC) &= ~(1L<<63); } unsigned int arch_install_breakpoint(void *pc) { unsigned int *ptr = (unsigned int *)pc; unsigned int result = *ptr; *ptr = BREAKPOINT_INST; os_flush_icache((os_vm_address_t)ptr, sizeof(unsigned int)); return result; } void arch_remove_breakpoint(void *pc, unsigned int orig_inst) { unsigned int *ptr = (unsigned int *)pc; *ptr = orig_inst; os_flush_icache((os_vm_address_t)pc, sizeof(unsigned int)); } static unsigned int *skipped_break_addr, displaced_after_inst, after_breakpoint; /* This returns a PC value. Lisp code is all in the 32-bit-addressable * space, so we should be ok with an unsigned int. */ unsigned int emulate_branch(os_context_t *context, unsigned int orig_inst) { int op = orig_inst >> 26; int reg_a = (orig_inst >> 21) & 0x1f; int reg_b = (orig_inst >> 16) & 0x1f; 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; */ switch(op) { case 0x1a: /* jmp, jsr, jsr_coroutine, ret */ *os_context_register_addr(context,reg_a) = *os_context_pc_addr(context); *os_context_pc_addr(context) = *os_context_register_addr(context,reg_b)& ~3; break; case 0x30: /* br */ *os_context_register_addr(context,reg_a)=*os_context_pc_addr(context); branch = 1; break; case 0x31: /* fbeq */ if (*(os_context_float_register_addr(context,reg_a))==0) branch = 1; break; case 0x32: /* fblt */ if (*os_context_float_register_addr(context,reg_a)<0) branch = 1; break; case 0x33: /* fble */ if (*os_context_float_register_addr(context,reg_a)<=0) branch = 1; break; case 0x34: /* bsr */ *os_context_register_addr(context,reg_a)=*os_context_pc_addr(context); branch = 1; break; case 0x35: /* fbne */ if (*os_context_register_addr(context,reg_a)!=0) branch = 1; break; case 0x36: /* fbge */ if (*os_context_float_register_addr(context,reg_a)>=0) branch = 1; break; case 0x37: /* fbgt */ if (*os_context_float_register_addr(context,reg_a)>0) branch = 1; break; case 0x38: /* blbc */ if ((*os_context_register_addr(context,reg_a)&1) == 0) branch = 1; break; case 0x39: /* beq */ if (*os_context_register_addr(context,reg_a)==0) branch = 1; break; case 0x3a: /* blt */ if (*os_context_register_addr(context,reg_a)<0) branch = 1; break; case 0x3b: /* ble */ if (*os_context_register_addr(context,reg_a)<=0) branch = 1; break; case 0x3c: /* blbs */ if ((*os_context_register_addr(context,reg_a)&1)!=0) branch = 1; break; case 0x3d: /* bne */ if (*os_context_register_addr(context,reg_a)!=0) branch = 1; break; case 0x3e: /* bge */ if (*os_context_register_addr(context,reg_a)>=0) branch = 1; break; case 0x3f: /* bgt */ if (*os_context_register_addr(context,reg_a)>0) branch = 1; break; } if (branch) next_pc += disp*4; return next_pc; } 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; int op = orig_inst >> 26;; orig_sigmask = *os_context_sigmask_addr(context); sigaddset_blockable(os_context_sigmask_addr(context)); /* Put the original instruction back. */ *pc = orig_inst; os_flush_icache((os_vm_address_t)pc, sizeof(unsigned int)); 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 int)); } void arch_handle_breakpoint(os_context_t *context) { *os_context_pc_addr(context) -=4; handle_breakpoint(context); } void arch_handle_fun_end_breakpoint(os_context_t *context) { *os_context_pc_addr(context) -=4; *os_context_pc_addr(context) = (int)handle_fun_end_breakpoint(context); } static void sigtrap_handler(int signal, siginfo_t *siginfo, os_context_t *context) { unsigned int code; #ifdef LISP_FEATURE_LINUX os_restore_fp_control(context); #endif /* 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 int)); 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 int)); *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))); handle_trap(context, code); } unsigned long arch_get_fp_control() { return ieee_get_fp_control(); } void arch_set_fp_control(unsigned long fp) { ieee_set_fp_control(fp); } void arch_install_interrupt_handlers() { undoably_install_low_level_interrupt_handler(SIGTRAP, sigtrap_handler); }