/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2005 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "%Z%%M% %I% %E% SMI" #include #include #include #include #include #include #include #include #include #define DTRACE_FMT3OP3_MASK 0x81000000 #define DTRACE_FMT3OP3 0x80000000 #define DTRACE_FMT3RS1_SHIFT 14 #define DTRACE_FMT3RD_SHIFT 25 #define DTRACE_DISP22_SHIFT 10 #define DTRACE_RMASK 0x1f #define DTRACE_REG_L0 16 #define DTRACE_REG_O7 15 #define DTRACE_REG_I0 24 #define DTRACE_REG_I6 30 #define DTRACE_RET 0x81c7e008 #define DTRACE_RETL 0x81c3e008 #define DTRACE_SAVE_MASK 0xc1f80000 #define DTRACE_SAVE 0x81e00000 #define DTRACE_RESTORE 0x81e80000 #define DTRACE_CALL_MASK 0xc0000000 #define DTRACE_CALL 0x40000000 #define DTRACE_JMPL_MASK 0x81f10000 #define DTRACE_JMPL 0x81c00000 #define DTRACE_BA_MASK 0xdfc00000 #define DTRACE_BA 0x10800000 #define DTRACE_BA_MAX 10 extern int dtrace_getupcstack_top(uint64_t *, int, uintptr_t *); extern int dtrace_getustackdepth_top(uintptr_t *); extern ulong_t dtrace_getreg_win(uint_t, uint_t); extern void dtrace_putreg_win(uint_t, ulong_t); extern int dtrace_fish(int, int, uintptr_t *); /* * This is similar in principle to getpcstack(), but there are several marked * differences in implementation: * * (a) dtrace_getpcstack() is called from probe context. Thus, the call * to flush_windows() from getpcstack() is a call to the probe-safe * equivalent here. * * (b) dtrace_getpcstack() is willing to sacrifice some performance to get * a correct stack. While consumers of getpcstack() are largely * subsystem-specific in-kernel debugging facilities, DTrace consumers * are arbitrary user-level analysis tools; dtrace_getpcstack() must * deliver as correct a stack as possible. Details on the issues * surrounding stack correctness are found below. * * (c) dtrace_getpcstack() _always_ fills in pcstack_limit pc_t's -- filling * in the difference between the stack depth and pcstack_limit with NULLs. * Due to this behavior dtrace_getpcstack() returns void. * * (d) dtrace_getpcstack() takes a third parameter, aframes, that * denotes the number of _artificial frames_ on the bottom of the * stack. An artificial frame is one induced by the provider; all * artificial frames are stripped off before frames are stored to * pcstack. * * (e) dtrace_getpcstack() takes a fourth parameter, pc, that indicates * an interrupted program counter (if any). This should be a non-NULL * value if and only if the hit probe is unanchored. (Anchored probes * don't fire through an interrupt source.) This parameter is used to * assure (b), above. */ void dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes, uint32_t *pc) { struct frame *fp, *nextfp, *minfp, *stacktop; int depth = 0; int on_intr, j = 0; uint32_t i, r; fp = (struct frame *)((caddr_t)dtrace_getfp() + STACK_BIAS); dtrace_flush_windows(); if (pc != NULL) { /* * If we've been passed a non-NULL pc, we need to determine * whether or not the specified program counter falls in a leaf * function. If it falls within a leaf function, we know that * %o7 is valid in its frame (and we can just drive on). If * it's a non-leaf, however, we know that %o7 is garbage in the * bottom frame. To trim this frame, we simply increment * aframes and drop into the stack-walking loop. * * To quickly determine if the specified program counter is in * a leaf function, we exploit the fact that leaf functions * tend to be short and non-leaf functions tend to frequently * perform operations that are only permitted in a non-leaf * function (e.g., using the %i's or %l's; calling a function; * performing a restore). We exploit these tendencies by * simply scanning forward from the specified %pc -- if we see * an operation only permitted in a non-leaf, we know we're in * a non-leaf; if we see a retl, we know we're in a leaf. * Fortunately, one need not perform anywhere near full * disassembly to effectively determine the former: determining * that an instruction is a format-3 instruction and decoding * its rd and rs1 fields, for example, requires very little * manipulation. Overall, this method of leaf determination * performs quite well: on average, we only examine between * 1.5 and 2.5 instructions before making the determination. * (Outliers do exist, however; of note is the non-leaf * function ip_sioctl_not_ours() which -- as of this writing -- * has a whopping 455 straight instructions that manipulate * only %g's and %o's.) */ int delay = 0, branches = 0, taken = 0; if (depth < pcstack_limit) pcstack[depth++] = (pc_t)pc; /* * Our heuristic is exactly that -- a heuristic -- and there * exists a possibility that we could be either be vectored * off into the weeds (by following a bogus branch) or could * wander off the end of the function and off the end of a * text mapping (by not following a conditional branch at the * end of the function that is effectively always taken). So * as a precautionary measure, we set the NOFAULT flag. */ DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); for (;;) { i = pc[j++]; if ((i & DTRACE_FMT3OP3_MASK) == DTRACE_FMT3OP3) { /* * This is a format-3 instruction. We can * look at rd and rs1. */ r = (i >> DTRACE_FMT3RS1_SHIFT) & DTRACE_RMASK; if (r >= DTRACE_REG_L0) goto nonleaf; r = (i >> DTRACE_FMT3RD_SHIFT) & DTRACE_RMASK; if (r >= DTRACE_REG_L0) goto nonleaf; if ((i & DTRACE_JMPL_MASK) == DTRACE_JMPL) { delay = 1; continue; } /* * If we see explicit manipulation with %o7 * as a destination register, we know that * %o7 is likely bogus -- and we treat this * function as a non-leaf. */ if (r == DTRACE_REG_O7) { if (delay) goto leaf; i &= DTRACE_JMPL_MASK; if (i == DTRACE_JMPL) { delay = 1; continue; } goto nonleaf; } } else { /* * If this is a call, it may or may not be * a leaf; we need to check the delay slot. */ if ((i & DTRACE_CALL_MASK) == DTRACE_CALL) { delay = 1; continue; } /* * If we see a ret it's not a leaf; if we * see a retl, it is a leaf. */ if (i == DTRACE_RET) goto nonleaf; if (i == DTRACE_RETL) goto leaf; /* * If this is a ba (annulled or not), then we * need to actually follow the branch. No, we * don't look at the delay slot -- hopefully * anything that can be gleaned from the delay * slot can also be gleaned from the branch * target. To prevent ourselves from iterating * infinitely, we clamp the number of branches * that we'll follow, and we refuse to follow * the same branch twice consecutively. In * both cases, we abort by deciding that we're * looking at a leaf. While in theory this * could be wrong (we could be in the middle of * a loop in a non-leaf that ends with a ba and * only manipulates outputs and globals in the * body of the loop -- therefore leading us to * the wrong conclusion), this doesn't seem to * crop up in practice. (Or rather, this * condition could not be deliberately induced, * despite concerted effort.) */ if ((i & DTRACE_BA_MASK) == DTRACE_BA) { if (++branches == DTRACE_BA_MAX || taken == j) goto nonleaf; taken = j; j += ((int)(i << DTRACE_DISP22_SHIFT) >> DTRACE_DISP22_SHIFT) - 1; continue; } /* * Finally, if it's a save, it should be * treated as a leaf; if it's a restore it * should not be treated as a leaf. */ if ((i & DTRACE_SAVE_MASK) == DTRACE_SAVE) goto leaf; if ((i & DTRACE_SAVE_MASK) == DTRACE_RESTORE) goto nonleaf; } if (delay) { /* * If this was a delay slot instruction and * we didn't pick it up elsewhere, this is a * non-leaf. */ goto nonleaf; } } nonleaf: aframes++; leaf: DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); } if ((on_intr = CPU_ON_INTR(CPU)) != 0) stacktop = (struct frame *)(CPU->cpu_intr_stack + SA(MINFRAME)); else stacktop = (struct frame *)curthread->t_stk; minfp = fp; while (depth < pcstack_limit) { nextfp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS); if (nextfp <= minfp || nextfp >= stacktop) { if (!on_intr && nextfp == stacktop && aframes != 0) { /* * If we are exactly at the top of the stack * with a non-zero number of artificial frames, * it must be that the stack is filled with * nothing _but_ artificial frames. In this * case, we assert that this is so, zero * pcstack, and return. */ ASSERT(aframes == 1); ASSERT(depth == 0); while (depth < pcstack_limit) pcstack[depth++] = NULL; return; } if (on_intr) { /* * Hop from interrupt stack to thread stack. */ stacktop = (struct frame *)curthread->t_stk; minfp = (struct frame *)curthread->t_stkbase; on_intr = 0; if (nextfp > minfp && nextfp < stacktop) continue; } else { /* * High-level interrupts may occur when %sp is * not necessarily contained in the stack * bounds implied by %g7 -- interrupt thread * management runs with %pil at DISP_LEVEL, * and high-level interrupts may thus occur * in windows when %sp and %g7 are not self- * consistent. If we call dtrace_getpcstack() * from a high-level interrupt that has occurred * in such a window, we will fail the above test * of nextfp against minfp/stacktop. If the * high-level interrupt has in turn interrupted * a non-passivated interrupt thread, we * will execute the below code with non-zero * aframes. We therefore want to assert that * aframes is zero _or_ we are in a high-level * interrupt -- but because cpu_intr_actv is * updated with high-level interrupts enabled, * we must reduce this to only asserting that * %pil is greater than DISP_LEVEL. */ ASSERT(aframes == 0 || dtrace_getipl() > DISP_LEVEL); pcstack[depth++] = (pc_t)fp->fr_savpc; } while (depth < pcstack_limit) pcstack[depth++] = NULL; return; } if (aframes > 0) { aframes--; } else { pcstack[depth++] = (pc_t)fp->fr_savpc; } fp = nextfp; minfp = fp; } } static int dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t sp) { proc_t *p = curproc; int ret = 0; ASSERT(pcstack == NULL || pcstack_limit > 0); if (p->p_model == DATAMODEL_NATIVE) { for (;;) { struct frame *fr = (struct frame *)(sp + STACK_BIAS); uintptr_t pc; if (sp == 0 || fr == NULL || !IS_P2ALIGNED((uintptr_t)fr, STACK_ALIGN)) break; pc = dtrace_fulword(&fr->fr_savpc); sp = dtrace_fulword(&fr->fr_savfp); if (pc == 0) break; ret++; if (pcstack != NULL) { *pcstack++ = pc; pcstack_limit--; if (pcstack_limit == 0) break; } } } else { for (;;) { struct frame32 *fr = (struct frame32 *)sp; uint32_t pc; if (sp == 0 || !IS_P2ALIGNED((uintptr_t)fr, STACK_ALIGN32)) break; pc = dtrace_fuword32(&fr->fr_savpc); sp = dtrace_fuword32(&fr->fr_savfp); if (pc == 0) break; ret++; if (pcstack != NULL) { *pcstack++ = pc; pcstack_limit--; if (pcstack_limit == 0) break; } } } return (ret); } void dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit) { klwp_t *lwp = ttolwp(curthread); proc_t *p = curproc; struct regs *rp; uintptr_t sp; int n; if (pcstack_limit <= 0) return; /* * If there's no user context we still need to zero the stack. */ if (lwp == NULL || p == NULL || (rp = lwp->lwp_regs) == NULL) goto zero; *pcstack++ = (uint64_t)p->p_pid; pcstack_limit--; if (pcstack_limit <= 0) return; *pcstack++ = (uint64_t)rp->r_pc; pcstack_limit--; if (pcstack_limit <= 0) return; if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) { *pcstack++ = (uint64_t)rp->r_o7; pcstack_limit--; if (pcstack_limit <= 0) return; } sp = rp->r_sp; n = dtrace_getupcstack_top(pcstack, pcstack_limit, &sp); ASSERT(n >= 0); ASSERT(n <= pcstack_limit); pcstack += n; pcstack_limit -= n; if (pcstack_limit <= 0) return; n = dtrace_getustack_common(pcstack, pcstack_limit, sp); ASSERT(n >= 0); ASSERT(n <= pcstack_limit); pcstack += n; pcstack_limit -= n; zero: while (pcstack_limit-- > 0) *pcstack++ = NULL; } int dtrace_getustackdepth(void) { klwp_t *lwp = ttolwp(curthread); proc_t *p = curproc; struct regs *rp; uintptr_t sp; int n = 1; if (lwp == NULL || p == NULL || (rp = lwp->lwp_regs) == NULL) return (0); if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAULT)) return (-1); sp = rp->r_sp; n += dtrace_getustackdepth_top(&sp); n += dtrace_getustack_common(NULL, 0, sp); /* * Add one more to the stack depth if we're in an entry probe as long * as the return address is non-NULL or there are additional frames * beyond that NULL return address. */ if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY) && (rp->r_o7 != NULL || n != 1)) n++; return (n); } void dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack, int pcstack_limit) { klwp_t *lwp = ttolwp(curthread); proc_t *p = ttoproc(curthread); struct regs *rp; uintptr_t sp; if (pcstack_limit <= 0) return; /* * If there's no user context we still need to zero the stack. */ if (lwp == NULL || p == NULL || (rp = lwp->lwp_regs) == NULL) goto zero; *pcstack++ = (uint64_t)p->p_pid; pcstack_limit--; if (pcstack_limit <= 0) return; if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) { *fpstack++ = 0; *pcstack++ = (uint64_t)rp->r_pc; pcstack_limit--; if (pcstack_limit <= 0) return; *fpstack++ = (uint64_t)rp->r_sp; *pcstack++ = (uint64_t)rp->r_o7; pcstack_limit--; } else { *fpstack++ = (uint64_t)rp->r_sp; *pcstack++ = (uint64_t)rp->r_pc; pcstack_limit--; } if (pcstack_limit <= 0) return; sp = rp->r_sp; dtrace_flush_user_windows(); if (p->p_model == DATAMODEL_NATIVE) { while (pcstack_limit > 0) { struct frame *fr = (struct frame *)(sp + STACK_BIAS); uintptr_t pc; if (sp == 0 || fr == NULL || ((uintptr_t)&fr->fr_savpc & 3) != 0 || ((uintptr_t)&fr->fr_savfp & 3) != 0) break; pc = dtrace_fulword(&fr->fr_savpc); sp = dtrace_fulword(&fr->fr_savfp); if (pc == 0) break; *fpstack++ = sp; *pcstack++ = pc; pcstack_limit--; } } else { while (pcstack_limit > 0) { struct frame32 *fr = (struct frame32 *)sp; uint32_t pc; if (sp == 0 || ((uintptr_t)&fr->fr_savpc & 3) != 0 || ((uintptr_t)&fr->fr_savfp & 3) != 0) break; pc = dtrace_fuword32(&fr->fr_savpc); sp = dtrace_fuword32(&fr->fr_savfp); if (pc == 0) break; *fpstack++ = sp; *pcstack++ = pc; pcstack_limit--; } } zero: while (pcstack_limit-- > 0) *pcstack++ = NULL; } uint64_t dtrace_getarg(int arg, int aframes) { uintptr_t val; struct frame *fp; uint64_t rval; /* * Account for the fact that dtrace_getarg() consumes an additional * stack frame. */ aframes++; if (arg < 6) { if (dtrace_fish(aframes, DTRACE_REG_I0 + arg, &val) == 0) return (val); } else { if (dtrace_fish(aframes, DTRACE_REG_I6, &val) == 0) { /* * We have a stack pointer; grab the argument. */ fp = (struct frame *)(val + STACK_BIAS); DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); rval = fp->fr_argx[arg - 6]; DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); return (rval); } } /* * There are other ways to do this. But the slow, painful way works * just fine. Because this requires some loads, we need to set * CPU_DTRACE_NOFAULT to protect against looking for an argument that * isn't there. */ fp = (struct frame *)((caddr_t)dtrace_getfp() + STACK_BIAS); dtrace_flush_windows(); DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); for (aframes -= 1; aframes; aframes--) fp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS); if (arg < 6) { rval = fp->fr_arg[arg]; } else { fp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS); rval = fp->fr_argx[arg - 6]; } DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); return (rval); } int dtrace_getstackdepth(int aframes) { struct frame *fp, *nextfp, *minfp, *stacktop; int depth = 0; int on_intr; fp = (struct frame *)((caddr_t)dtrace_getfp() + STACK_BIAS); dtrace_flush_windows(); if ((on_intr = CPU_ON_INTR(CPU)) != 0) stacktop = (struct frame *)CPU->cpu_intr_stack + SA(MINFRAME); else stacktop = (struct frame *)curthread->t_stk; minfp = fp; for (;;) { nextfp = (struct frame *)((caddr_t)fp->fr_savfp + STACK_BIAS); if (nextfp <= minfp || nextfp >= stacktop) { if (on_intr) { /* * Hop from interrupt stack to thread stack. */ stacktop = (struct frame *)curthread->t_stk; minfp = (struct frame *)curthread->t_stkbase; on_intr = 0; continue; } return (++depth); } if (aframes > 0) { aframes--; } else { depth++; } fp = nextfp; minfp = fp; } } /* * This uses the same register numbering scheme as in sys/procfs_isa.h. */ ulong_t dtrace_getreg(struct regs *rp, uint_t reg) { ulong_t value; uintptr_t fp; struct machpcb *mpcb; if (reg == R_G0) return (0); if (reg <= R_G7) return ((&rp->r_g1)[reg - 1]); if (reg > R_I7) { switch (reg) { case R_CCR: return ((rp->r_tstate >> TSTATE_CCR_SHIFT) & TSTATE_CCR_MASK); case R_PC: return (rp->r_pc); case R_nPC: return (rp->r_npc); case R_Y: return (rp->r_y); case R_ASI: return ((rp->r_tstate >> TSTATE_ASI_SHIFT) & TSTATE_ASI_MASK); case R_FPRS: return (dtrace_getfprs()); default: DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP); return (0); } } /* * We reach go to the fake restore case if the probe we hit was a pid * return probe on a restore instruction. We partially emulate the * restore in the kernel and then execute a simple restore * instruction that we've secreted away to do the actual register * window manipulation. We need to go one register window further * down to get at the %ls, and %is and we need to treat %os like %is * to pull them out of the topmost user frame. */ if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAKERESTORE)) { if (reg > R_O7) goto fake_restore; else reg += R_I0 - R_O0; } else if (reg <= R_O7) { return ((&rp->r_g1)[reg - 1]); } if (dtrace_getotherwin() > 0) return (dtrace_getreg_win(reg, 1)); mpcb = (struct machpcb *)((caddr_t)rp - REGOFF); if (curproc->p_model == DATAMODEL_NATIVE) { struct frame *fr = (void *)(rp->r_sp + STACK_BIAS); if (mpcb->mpcb_wbcnt > 0) { struct rwindow *rwin = (void *)mpcb->mpcb_wbuf; int i = mpcb->mpcb_wbcnt; do { i--; if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp) return (rwin[i].rw_local[reg - 16]); } while (i > 0); } DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); value = dtrace_fulword(&fr->fr_local[reg - 16]); DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); } else { struct frame32 *fr = (void *)(caddr32_t)rp->r_sp; if (mpcb->mpcb_wbcnt > 0) { struct rwindow32 *rwin = (void *)mpcb->mpcb_wbuf; int i = mpcb->mpcb_wbcnt; do { i--; if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp) return (rwin[i].rw_local[reg - 16]); } while (i > 0); } DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); value = dtrace_fuword32(&fr->fr_local[reg - 16]); DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); } return (value); fake_restore: ASSERT(R_L0 <= reg && reg <= R_I7); /* * We first look two user windows down to see if we can dig out * the register we're looking for. */ if (dtrace_getotherwin() > 1) return (dtrace_getreg_win(reg, 2)); /* * First we need to get the frame pointer and then we perform * the same computation as in the non-fake-o-restore case. */ mpcb = (struct machpcb *)((caddr_t)rp - REGOFF); if (dtrace_getotherwin() > 0) { fp = dtrace_getreg_win(R_FP, 1); goto got_fp; } if (curproc->p_model == DATAMODEL_NATIVE) { struct frame *fr = (void *)(rp->r_sp + STACK_BIAS); if (mpcb->mpcb_wbcnt > 0) { struct rwindow *rwin = (void *)mpcb->mpcb_wbuf; int i = mpcb->mpcb_wbcnt; do { i--; if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp) { fp = rwin[i].rw_fp; goto got_fp; } } while (i > 0); } DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); fp = dtrace_fulword(&fr->fr_savfp); DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); if (cpu_core[CPU->cpu_id].cpuc_dtrace_flags & CPU_DTRACE_FAULT) return (0); } else { struct frame32 *fr = (void *)(caddr32_t)rp->r_sp; if (mpcb->mpcb_wbcnt > 0) { struct rwindow32 *rwin = (void *)mpcb->mpcb_wbuf; int i = mpcb->mpcb_wbcnt; do { i--; if ((long)mpcb->mpcb_spbuf[i] == rp->r_sp) { fp = rwin[i].rw_fp; goto got_fp; } } while (i > 0); } DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); fp = dtrace_fuword32(&fr->fr_savfp); DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); if (cpu_core[CPU->cpu_id].cpuc_dtrace_flags & CPU_DTRACE_FAULT) return (0); } got_fp: if (curproc->p_model == DATAMODEL_NATIVE) { struct frame *fr = (void *)(fp + STACK_BIAS); if (mpcb->mpcb_wbcnt > 0) { struct rwindow *rwin = (void *)mpcb->mpcb_wbuf; int i = mpcb->mpcb_wbcnt; do { i--; if ((long)mpcb->mpcb_spbuf[i] == fp) return (rwin[i].rw_local[reg - 16]); } while (i > 0); } DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); value = dtrace_fulword(&fr->fr_local[reg - 16]); DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); } else { struct frame32 *fr = (void *)(caddr32_t)fp; if (mpcb->mpcb_wbcnt > 0) { struct rwindow32 *rwin = (void *)mpcb->mpcb_wbuf; int i = mpcb->mpcb_wbcnt; do { i--; if ((long)mpcb->mpcb_spbuf[i] == fp) return (rwin[i].rw_local[reg - 16]); } while (i > 0); } DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); value = dtrace_fuword32(&fr->fr_local[reg - 16]); DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); } return (value); }