/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2005,2008 Joseph Koshy * Copyright (c) 2007 The FreeBSD Foundation * All rights reserved. * * Portions of this software were developed by A. Joseph Koshy under * sponsorship from the FreeBSD Foundation and Google, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/param.h> #include <sys/systm.h> #include <sys/bus.h> #include <sys/pmc.h> #include <vm/vm.h> #include <vm/pmap.h> #include <machine/cpu.h> #include <machine/cputypes.h> #include <machine/intr_machdep.h> /* For x86/apicvar.h */ #include <machine/md_var.h> #include <machine/pmc_mdep.h> #include <machine/stack.h> #include <machine/vmparam.h> #include <x86/apicvar.h> #include "hwpmc_soft.h" /* * Attempt to walk a user call stack using a too-simple algorithm. * In the general case we need unwind information associated with * the executable to be able to walk the user stack. * * We are handed a trap frame laid down at the time the PMC interrupt * was taken. If the application is using frame pointers, the saved * PC value could be: * a. at the beginning of a function before the stack frame is laid * down, * b. just before a 'ret', after the stack frame has been taken off, * c. somewhere else in the function with a valid stack frame being * present, * * If the application is not using frame pointers, this algorithm will * fail to yield an interesting call chain. * * TODO: figure out a way to use unwind information. */ int pmc_save_user_callchain(uintptr_t *cc, int nframes, struct trapframe *tf) { int n; uint32_t instr; uintptr_t fp, oldfp, pc, r, sp; KASSERT(TRAPF_USERMODE(tf), ("[x86,%d] Not a user trap frame tf=%p", __LINE__, (void *) tf)); pc = PMC_TRAPFRAME_TO_PC(tf); oldfp = fp = PMC_TRAPFRAME_TO_FP(tf); sp = PMC_TRAPFRAME_TO_USER_SP(tf); *cc++ = pc; n = 1; r = fp + sizeof(uintptr_t); /* points to return address */ if (!PMC_IN_USERSPACE(pc)) return (n); if (copyin((void *) pc, &instr, sizeof(instr)) != 0) return (n); if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) || PMC_AT_FUNCTION_EPILOGUE_RET(instr)) { /* ret */ if (copyin((void *) sp, &pc, sizeof(pc)) != 0) return (n); } else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) { sp += sizeof(uintptr_t); if (copyin((void *) sp, &pc, sizeof(pc)) != 0) return (n); } else if (copyin((void *) r, &pc, sizeof(pc)) != 0 || copyin((void *) fp, &fp, sizeof(fp)) != 0) return (n); for (; n < nframes;) { if (pc == 0 || !PMC_IN_USERSPACE(pc)) break; *cc++ = pc; n++; if (fp < oldfp) break; r = fp + sizeof(uintptr_t); /* address of return address */ oldfp = fp; if (copyin((void *) r, &pc, sizeof(pc)) != 0 || copyin((void *) fp, &fp, sizeof(fp)) != 0) break; } return (n); } /* * Walking the kernel call stack. * * We are handed the trap frame laid down at the time the PMC * interrupt was taken. The saved PC could be: * a. in the lowlevel trap handler, meaning that there isn't a C stack * to traverse, * b. at the beginning of a function before the stack frame is laid * down, * c. just before a 'ret', after the stack frame has been taken off, * d. somewhere else in a function with a valid stack frame being * present. * * In case (d), the previous frame pointer is at [%ebp]/[%rbp] and * the return address is at [%ebp+4]/[%rbp+8]. * * For cases (b) and (c), the return address is at [%esp]/[%rsp] and * the frame pointer doesn't need to be changed when going up one * level in the stack. * * For case (a), we check if the PC lies in low-level trap handling * code, and if so we terminate our trace. */ int __nosanitizeaddress __nosanitizememory pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf) { uintptr_t fp, pc, ra, sp; uint32_t instr; int n; KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace", __LINE__)); pc = PMC_TRAPFRAME_TO_PC(tf); fp = PMC_TRAPFRAME_TO_FP(tf); sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf); *cc++ = pc; ra = fp + sizeof(uintptr_t); /* points to return address */ if (nframes <= 1) return (1); if (PMC_IN_TRAP_HANDLER(pc) || !PMC_IN_KERNEL(pc) || !PMC_IN_KERNEL_STACK(ra) || !PMC_IN_KERNEL_STACK(sp) || !PMC_IN_KERNEL_STACK(fp)) return (1); instr = *(uint32_t *)pc; /* * Determine whether the interrupted function was in the * processing of either laying down its stack frame or taking * it off. * * If we haven't started laying down a stack frame, or are * just about to return, then our caller's address is at * *sp, and we don't have a frame to unwind. */ if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) || PMC_AT_FUNCTION_EPILOGUE_RET(instr)) pc = *(uintptr_t *) sp; else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) { /* * The code was midway through laying down a frame. * At this point sp[0] has a frame back pointer, * and the caller's address is therefore at sp[1]. */ sp += sizeof(uintptr_t); if (!PMC_IN_KERNEL_STACK(sp)) return (1); pc = *(uintptr_t *)sp; } else { /* * Not in the function prologue or epilogue. */ pc = *(uintptr_t *)ra; fp = *(uintptr_t *)fp; } for (n = 1; n < nframes; n++) { *cc++ = pc; if (PMC_IN_TRAP_HANDLER(pc)) break; ra = fp + sizeof(uintptr_t); if (!PMC_IN_KERNEL_STACK(fp) || !PMC_IN_KERNEL_STACK(ra)) break; pc = *(uintptr_t *)ra; fp = *(uintptr_t *)fp; } return (n); } /* * Machine dependent initialization for x86 class platforms. */ struct pmc_mdep * pmc_md_initialize(void) { int i; struct pmc_mdep *md = NULL; /* determine the CPU kind */ if (cpu_vendor_id == CPU_VENDOR_AMD || cpu_vendor_id == CPU_VENDOR_HYGON) md = pmc_amd_initialize(); else if (cpu_vendor_id == CPU_VENDOR_INTEL) md = pmc_intel_initialize(); if (md == NULL) return (NULL); nmi_register_handler(md->pmd_intr); /* disallow sampling if we do not have an LAPIC */ if (!lapic_enable_pcint()) for (i = 0; i < md->pmd_nclass; i++) { if (i == PMC_CLASS_INDEX_SOFT) continue; md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT; } return (md); } void pmc_md_finalize(struct pmc_mdep *md) { if (md != NULL) { lapic_disable_pcint(); nmi_remove_handler(md->pmd_intr); } if (cpu_vendor_id == CPU_VENDOR_AMD || cpu_vendor_id == CPU_VENDOR_HYGON) pmc_amd_finalize(md); else if (cpu_vendor_id == CPU_VENDOR_INTEL) pmc_intel_finalize(md); else KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__)); }
