kinst: port to arm64
Reviewed by: markj Approved by: markj (mentor) Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D40337
This commit is contained in:
parent
2517b2085b
commit
07864a8a24
455
sys/cddl/dev/kinst/aarch64/kinst_isa.c
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455
sys/cddl/dev/kinst/aarch64/kinst_isa.c
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@ -0,0 +1,455 @@
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/*
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* SPDX-License-Identifier: CDDL 1.0
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*
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* Copyright (c) 2022 Christos Margiolis <christos@FreeBSD.org>
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* Copyright (c) 2022 Mark Johnston <markj@FreeBSD.org>
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* Copyright (c) 2023 The FreeBSD Foundation
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*
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* Portions of this software were developed by Christos Margiolis
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* <christos@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
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*/
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#include <sys/param.h>
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#include <sys/dtrace.h>
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#include <cddl/dev/dtrace/dtrace_cddl.h>
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#include "kinst.h"
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DPCPU_DEFINE_STATIC(struct kinst_cpu_state, kinst_state);
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static int
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kinst_emulate(struct trapframe *frame, const struct kinst_probe *kp)
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{
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kinst_patchval_t instr = kp->kp_savedval;
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uint64_t imm;
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uint8_t cond, reg, bitpos;
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bool res;
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if (((instr >> 24) & 0x1f) == 0b10000) {
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/* adr/adrp */
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reg = instr & 0x1f;
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imm = (instr >> 29) & 0x3;
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imm |= ((instr >> 5) & 0x0007ffff) << 2;
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if (((instr >> 31) & 0x1) == 0) {
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/* adr */
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if (imm & 0x0000000000100000)
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imm |= 0xfffffffffff00000;
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frame->tf_x[reg] = frame->tf_elr + imm;
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} else {
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/* adrp */
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imm <<= 12;
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if (imm & 0x0000000100000000)
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imm |= 0xffffffff00000000;
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frame->tf_x[reg] = (frame->tf_elr & ~0xfff) + imm;
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}
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frame->tf_elr += INSN_SIZE;
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} else if (((instr >> 26) & 0x3f) == 0b000101) {
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/* b */
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imm = instr & 0x03ffffff;
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if (imm & 0x0000000002000000)
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imm |= 0xfffffffffe000000;
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frame->tf_elr += imm << 2;
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} else if (((instr >> 24) & 0xff) == 0b01010100) {
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/* b.cond */
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imm = (instr >> 5) & 0x0007ffff;
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if (imm & 0x0000000000040000)
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imm |= 0xfffffffffffc0000;
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cond = instr & 0xf;
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switch ((cond >> 1) & 0x7) {
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case 0b000: /* eq/ne */
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res = (frame->tf_spsr & PSR_Z) != 0;
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break;
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case 0b001: /* cs/cc */
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res = (frame->tf_spsr & PSR_C) != 0;
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break;
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case 0b010: /* mi/pl */
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res = (frame->tf_spsr & PSR_N) != 0;
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break;
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case 0b011: /* vs/vc */
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res = (frame->tf_spsr & PSR_V) != 0;
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break;
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case 0b100: /* hi/ls */
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res = ((frame->tf_spsr & PSR_C) != 0) &&
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((frame->tf_spsr & PSR_Z) == 0);
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break;
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case 0b101: /* ge/lt */
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res = ((frame->tf_spsr & PSR_N) != 0) ==
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((frame->tf_spsr & PSR_V) != 0);
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break;
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case 0b110: /* gt/le */
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res = ((frame->tf_spsr & PSR_Z) == 0) &&
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(((frame->tf_spsr & PSR_N) != 0) ==
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((frame->tf_spsr & PSR_V) != 0));
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break;
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case 0b111: /* al */
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res = 1;
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break;
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}
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if ((cond & 0x1) && cond != 0b1111)
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res = !res;
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if (res)
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frame->tf_elr += imm << 2;
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else
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frame->tf_elr += INSN_SIZE;
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} else if (((instr >> 26) & 0x3f) == 0b100101) {
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/* bl */
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imm = instr & 0x03ffffff;
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if (imm & 0x0000000002000000)
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imm |= 0xfffffffffe000000;
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frame->tf_lr = frame->tf_elr + INSN_SIZE;
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frame->tf_elr += imm << 2;
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} else if (((instr >> 25) & 0x3f) == 0b011010) {
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/* cbnz/cbz */
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cond = (instr >> 24) & 0x1;
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reg = instr & 0x1f;
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imm = (instr >> 5) & 0x0007ffff;
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if (imm & 0x0000000000040000)
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imm |= 0xfffffffffffc0000;
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if (cond == 1 && frame->tf_x[reg] != 0)
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/* cbnz */
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frame->tf_elr += imm << 2;
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else if (cond == 0 && frame->tf_x[reg] == 0)
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/* cbz */
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frame->tf_elr += imm << 2;
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else
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frame->tf_elr += INSN_SIZE;
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} else if (((instr >> 25) & 0x3f) == 0b011011) {
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/* tbnz/tbz */
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cond = (instr >> 24) & 0x1;
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reg = instr & 0x1f;
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bitpos = (instr >> 19) & 0x1f;
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bitpos |= ((instr >> 31) & 0x1) << 5;
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imm = (instr >> 5) & 0x3fff;
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if (imm & 0x0000000000002000)
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imm |= 0xffffffffffffe000;
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if (cond == 1 && (frame->tf_x[reg] & (1 << bitpos)) != 0)
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/* tbnz */
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frame->tf_elr += imm << 2;
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else if (cond == 0 && (frame->tf_x[reg] & (1 << bitpos)) == 0)
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/* tbz */
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frame->tf_elr += imm << 2;
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else
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frame->tf_elr += INSN_SIZE;
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}
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return (0);
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}
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static int
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kinst_jump_next_instr(struct trapframe *frame, const struct kinst_probe *kp)
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{
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frame->tf_elr = (register_t)((const uint8_t *)kp->kp_patchpoint +
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INSN_SIZE);
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return (0);
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}
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static void
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kinst_trampoline_populate(struct kinst_probe *kp)
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{
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static uint32_t bpt = KINST_PATCHVAL;
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kinst_memcpy(kp->kp_tramp, &kp->kp_savedval, INSN_SIZE);
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kinst_memcpy(&kp->kp_tramp[INSN_SIZE], &bpt, INSN_SIZE);
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cpu_icache_sync_range((vm_offset_t)kp->kp_tramp,
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(vm_size_t)KINST_TRAMP_SIZE);
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}
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/*
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* There are two ways by which an instruction is traced:
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*
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* - By using the trampoline.
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* - By emulating it in software (see kinst_emulate()).
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*
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* The trampoline is used for instructions that can be copied and executed
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* as-is without additional modification. However, instructions that use
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* PC-relative addressing have to be emulated, because ARM64 doesn't allow
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* encoding of large displacements in a single instruction, and since we cannot
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* clobber a register in order to encode the two-instruction sequence needed to
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* create large displacements, we cannot use the trampoline at all.
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* Fortunately, the instructions are simple enough to be emulated in just a few
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* lines of code.
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*
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* The problem discussed above also means that, unlike amd64, we cannot encode
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* a far-jump back from the trampoline to the next instruction. The mechanism
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* employed to achieve this functionality, is to use a breakpoint instead of a
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* jump after the copied instruction. This breakpoint is detected and handled
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* by kinst_invop(), which performs the jump back to the next instruction
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* manually (see kinst_jump_next_instr()).
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*/
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int
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kinst_invop(uintptr_t addr, struct trapframe *frame, uintptr_t scratch)
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{
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solaris_cpu_t *cpu;
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struct kinst_cpu_state *ks;
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const struct kinst_probe *kp;
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ks = DPCPU_PTR(kinst_state);
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/*
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* Detect if the breakpoint was triggered by the trampoline, and
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* manually set the PC to the next instruction.
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*/
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if (ks->state == KINST_PROBE_FIRED &&
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addr == (uintptr_t)(ks->kp->kp_tramp + INSN_SIZE)) {
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/*
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* Restore interrupts if they were enabled prior to the first
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* breakpoint.
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*/
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if ((ks->status & PSR_I) == 0)
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frame->tf_spsr &= ~PSR_I;
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ks->state = KINST_PROBE_ARMED;
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return (kinst_jump_next_instr(frame, ks->kp));
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}
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LIST_FOREACH(kp, KINST_GETPROBE(addr), kp_hashnext) {
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if ((uintptr_t)kp->kp_patchpoint == addr)
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break;
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}
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if (kp == NULL)
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return (0);
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cpu = &solaris_cpu[curcpu];
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cpu->cpu_dtrace_caller = addr;
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dtrace_probe(kp->kp_id, 0, 0, 0, 0, 0);
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cpu->cpu_dtrace_caller = 0;
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if (kp->kp_md.emulate)
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return (kinst_emulate(frame, kp));
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ks->state = KINST_PROBE_FIRED;
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ks->kp = kp;
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/*
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* Cache the current SPSR and clear interrupts for the duration
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* of the double breakpoint.
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*/
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ks->status = frame->tf_spsr;
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frame->tf_spsr |= PSR_I;
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frame->tf_elr = (register_t)kp->kp_tramp;
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return (0);
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}
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void
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kinst_patch_tracepoint(struct kinst_probe *kp, kinst_patchval_t val)
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{
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vm_offset_t addr;
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if (!arm64_get_writable_addr((vm_offset_t)kp->kp_patchpoint, &addr))
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panic("%s: Unable to write new instruction", __func__);
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*(kinst_patchval_t *)addr = val;
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cpu_icache_sync_range((vm_offset_t)kp->kp_patchpoint,
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(vm_size_t)INSN_SIZE);
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}
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static void
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kinst_instr_dissect(struct kinst_probe *kp)
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{
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struct kinst_probe_md *kpmd;
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kinst_patchval_t instr = kp->kp_savedval;
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kpmd = &kp->kp_md;
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kpmd->emulate = false;
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if (((instr >> 24) & 0x1f) == 0b10000)
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kpmd->emulate = true; /* adr/adrp */
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else if (((instr >> 26) & 0x3f) == 0b000101)
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kpmd->emulate = true; /* b */
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else if (((instr >> 24) & 0xff) == 0b01010100)
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kpmd->emulate = true; /* b.cond */
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else if (((instr >> 26) & 0x3f) == 0b100101)
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kpmd->emulate = true; /* bl */
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else if (((instr >> 25) & 0x3f) == 0b011010)
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kpmd->emulate = true; /* cbnz/cbz */
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else if (((instr >> 25) & 0x3f) == 0b011011)
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kpmd->emulate = true; /* tbnz/tbz */
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if (!kpmd->emulate)
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kinst_trampoline_populate(kp);
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}
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static bool
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kinst_instr_ldx(kinst_patchval_t instr)
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{
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if (((instr >> 22) & 0xff) == 0b00100001)
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return (true);
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return (false);
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}
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static bool
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kinst_instr_stx(kinst_patchval_t instr)
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{
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if (((instr >> 22) & 0xff) == 0b00100000)
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return (true);
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return (false);
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}
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int
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kinst_make_probe(linker_file_t lf, int symindx, linker_symval_t *symval,
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void *opaque)
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{
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struct kinst_probe *kp;
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dtrace_kinst_probedesc_t *pd;
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const char *func;
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kinst_patchval_t *instr, *limit, *tmp;
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int n, off;
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bool ldxstx_block, found;
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pd = opaque;
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func = symval->name;
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if (kinst_excluded(func))
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return (0);
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if (strcmp(func, pd->kpd_func) != 0)
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return (0);
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instr = (kinst_patchval_t *)(symval->value);
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limit = (kinst_patchval_t *)(symval->value + symval->size);
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if (instr >= limit)
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return (0);
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tmp = instr;
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/*
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* Ignore any bti instruction at the start of the function
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* we need to keep it there for any indirect branches calling
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* the function on Armv8.5+
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*/
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if ((*tmp & BTI_MASK) == BTI_INSTR)
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tmp++;
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/* Look for stp (pre-indexed) operation */
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found = false;
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/*
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* If the first instruction is a nop it's a specially marked
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* asm function. We only support a nop first as it's not a normal
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* part of the function prologue.
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*/
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if (*tmp == NOP_INSTR)
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found = true;
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for (; !found && tmp < limit; tmp++) {
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/*
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* Functions start with "stp xt1, xt2, [xn, <const>]!" or
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* "sub sp, sp, <const>".
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*
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* Sometimes the compiler will have a sub instruction that is
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* not of the above type so don't stop if we see one.
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*/
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if ((*tmp & LDP_STP_MASK) == STP_64) {
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/*
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* Assume any other store of this type means we are
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* past the function prolog.
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*/
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if (((*tmp >> ADDR_SHIFT) & ADDR_MASK) == 31)
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found = true;
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} else if ((*tmp & SUB_MASK) == SUB_INSTR &&
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((*tmp >> SUB_RD_SHIFT) & SUB_R_MASK) == 31 &&
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((*tmp >> SUB_RN_SHIFT) & SUB_R_MASK) == 31)
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found = true;
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}
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if (!found)
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return (0);
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ldxstx_block = false;
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for (n = 0; instr < limit; instr++) {
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off = (int)((uint8_t *)instr - (uint8_t *)symval->value);
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/*
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* Skip LDX/STX blocks that contain atomic operations. If a
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* breakpoint is placed in a LDX/STX block, we violate the
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* operation and the loop might fail.
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*/
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if (kinst_instr_ldx(*instr))
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ldxstx_block = true;
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else if (kinst_instr_stx(*instr)) {
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ldxstx_block = false;
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continue;
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}
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if (ldxstx_block)
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continue;
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/*
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* XXX: Skip ADR and ADRP instructions. The arm64 exception
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* handler has a micro-optimization where it doesn't restore
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* callee-saved registers when returning from exceptions in
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* EL1. This results in a panic when the kinst emulation code
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* modifies one of those registers.
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*/
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if (((*instr >> 24) & 0x1f) == 0b10000)
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continue;
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if (pd->kpd_off != -1 && off != pd->kpd_off)
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continue;
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/*
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* Prevent separate dtrace(1) instances from creating copies of
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* the same probe.
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*/
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LIST_FOREACH(kp, KINST_GETPROBE(instr), kp_hashnext) {
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if (strcmp(kp->kp_func, func) == 0 &&
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strtol(kp->kp_name, NULL, 10) == off)
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return (0);
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}
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if (++n > KINST_PROBETAB_MAX) {
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KINST_LOG("probe list full: %d entries", n);
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return (ENOMEM);
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}
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kp = malloc(sizeof(struct kinst_probe), M_KINST,
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M_WAITOK | M_ZERO);
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kp->kp_func = func;
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snprintf(kp->kp_name, sizeof(kp->kp_name), "%d", off);
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kp->kp_patchpoint = instr;
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kp->kp_savedval = *instr;
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kp->kp_patchval = KINST_PATCHVAL;
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if ((kp->kp_tramp = kinst_trampoline_alloc(M_WAITOK)) == NULL) {
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KINST_LOG("cannot allocate trampoline for %p", instr);
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return (ENOMEM);
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}
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kinst_instr_dissect(kp);
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kinst_probe_create(kp, lf);
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}
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if (ldxstx_block)
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KINST_LOG("warning: unterminated LDX/STX block");
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return (0);
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}
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int
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kinst_md_init(void)
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{
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struct kinst_cpu_state *ks;
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int cpu;
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CPU_FOREACH(cpu) {
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ks = DPCPU_PTR(kinst_state);
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ks->state = KINST_PROBE_ARMED;
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}
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return (0);
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}
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void
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kinst_md_deinit(void)
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{
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}
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/*
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* Exclude machine-dependent functions that are not safe-to-trace.
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*/
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bool
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kinst_md_excluded(const char *name)
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{
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if (strcmp(name, "handle_el1h_sync") == 0 ||
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strcmp(name, "do_el1h_sync") == 0)
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return (true);
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return (false);
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}
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26
sys/cddl/dev/kinst/aarch64/kinst_isa.h
Normal file
26
sys/cddl/dev/kinst/aarch64/kinst_isa.h
Normal file
@ -0,0 +1,26 @@
|
||||
/*
|
||||
* SPDX-License-Identifier: CDDL 1.0
|
||||
*
|
||||
* Copyright (c) 2023 The FreeBSD Foundation
|
||||
*
|
||||
* This software was developed by Christos Margiolis <christos@FreeBSD.org>
|
||||
* under sponsorship from the FreeBSD Foundation.
|
||||
*/
|
||||
|
||||
#ifndef _KINST_ISA_H_
|
||||
#define _KINST_ISA_H_
|
||||
|
||||
#define KINST_PATCHVAL DTRACE_PATCHVAL
|
||||
|
||||
/*
|
||||
* The trampoline contains [instruction, brk].
|
||||
*/
|
||||
#define KINST_TRAMP_SIZE 8
|
||||
|
||||
typedef uint32_t kinst_patchval_t;
|
||||
|
||||
struct kinst_probe_md {
|
||||
bool emulate; /* emulate in sw */
|
||||
};
|
||||
|
||||
#endif /* _KINST_ISA_H_ */
|
@ -21,7 +21,7 @@ SUBDIR+= fasttrap systrace_linux
|
||||
SUBDIR+= systrace_linux32
|
||||
SUBDIR+= kinst
|
||||
.endif
|
||||
.if ${MACHINE_CPUARCH} == "riscv"
|
||||
.if ${MACHINE_CPUARCH} == "riscv" || ${MACHINE_CPUARCH} == "aarch64"
|
||||
SUBDIR+= kinst
|
||||
.endif
|
||||
.if ${MACHINE_CPUARCH} == "powerpc"
|
||||
|
Loading…
Reference in New Issue
Block a user