diff options
Diffstat (limited to 'arch/arm64/kernel/probes/decode-insn.c')
| -rw-r--r-- | arch/arm64/kernel/probes/decode-insn.c | 68 |
1 files changed, 41 insertions, 27 deletions
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index 6bf6657a5a52..4137cc5ef031 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -1,16 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * arch/arm64/kernel/probes/decode-insn.c * * Copyright (C) 2013 Linaro Limited. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. */ #include <linux/kernel.h> @@ -32,12 +24,13 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) * currently safe. Lastly, MSR instructions can do any number of nasty * things we can't handle during single-stepping. */ - if (aarch64_get_insn_class(insn) == AARCH64_INSN_CLS_BR_SYS) { + if (aarch64_insn_is_class_branch_sys(insn)) { if (aarch64_insn_is_branch(insn) || aarch64_insn_is_msr_imm(insn) || aarch64_insn_is_msr_reg(insn) || aarch64_insn_is_exception(insn) || - aarch64_insn_is_eret(insn)) + aarch64_insn_is_eret(insn) || + aarch64_insn_is_eret_auth(insn)) return false; /* @@ -50,11 +43,13 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) != AARCH64_INSN_SPCLREG_DAIF; /* - * The HINT instruction is is problematic when single-stepping, - * except for the NOP case. + * The HINT instruction is steppable only if it is in whitelist + * and the rest of other such instructions are blocked for + * single stepping as they may cause exception or other + * unintended behaviour. */ if (aarch64_insn_is_hint(insn)) - return aarch64_insn_is_nop(insn); + return aarch64_insn_is_steppable_hint(insn); return true; } @@ -63,10 +58,13 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) * Instructions which load PC relative literals are not going to work * when executed from an XOL slot. Instructions doing an exclusive * load/store are not going to complete successfully when single-step - * exception handling happens in the middle of the sequence. + * exception handling happens in the middle of the sequence. Memory + * copy/set instructions require that all three instructions be placed + * consecutively in memory. */ if (aarch64_insn_uses_literal(insn) || - aarch64_insn_is_exclusive(insn)) + aarch64_insn_is_exclusive(insn) || + aarch64_insn_is_mops(insn)) return false; return true; @@ -78,9 +76,18 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) * INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot. */ enum probe_insn __kprobes -arm_probe_decode_insn(probe_opcode_t insn, struct arch_probe_insn *api) +arm_probe_decode_insn(u32 insn, struct arch_probe_insn *api) { /* + * While 'nop' instruction can execute in the out-of-line slot, + * simulating them in breakpoint handling offers better performance. + */ + if (aarch64_insn_is_nop(insn)) { + api->handler = simulate_nop; + return INSN_GOOD_NO_SLOT; + } + + /* * Instructions reading or modifying the PC won't work from the XOL * slot. */ @@ -101,13 +108,10 @@ arm_probe_decode_insn(probe_opcode_t insn, struct arch_probe_insn *api) aarch64_insn_is_bl(insn)) { api->handler = simulate_b_bl; } else if (aarch64_insn_is_br(insn) || - aarch64_insn_is_blr(insn) || - aarch64_insn_is_ret(insn)) { - api->handler = simulate_br_blr_ret; - } else if (aarch64_insn_is_ldr_lit(insn)) { - api->handler = simulate_ldr_literal; - } else if (aarch64_insn_is_ldrsw_lit(insn)) { - api->handler = simulate_ldrsw_literal; + aarch64_insn_is_blr(insn)) { + api->handler = simulate_br_blr; + } else if (aarch64_insn_is_ret(insn)) { + api->handler = simulate_ret; } else { /* * Instruction cannot be stepped out-of-line and we don't @@ -142,9 +146,20 @@ enum probe_insn __kprobes arm_kprobe_decode_insn(kprobe_opcode_t *addr, struct arch_specific_insn *asi) { enum probe_insn decoded; - probe_opcode_t insn = le32_to_cpu(*addr); - probe_opcode_t *scan_end = NULL; + u32 insn = le32_to_cpu(*addr); + kprobe_opcode_t *scan_end = NULL; unsigned long size = 0, offset = 0; + struct arch_probe_insn *api = &asi->api; + + if (aarch64_insn_is_ldr_lit(insn)) { + api->handler = simulate_ldr_literal; + decoded = INSN_GOOD_NO_SLOT; + } else if (aarch64_insn_is_ldrsw_lit(insn)) { + api->handler = simulate_ldrsw_literal; + decoded = INSN_GOOD_NO_SLOT; + } else { + decoded = arm_probe_decode_insn(insn, &asi->api); + } /* * If there's a symbol defined in front of and near enough to @@ -162,7 +177,6 @@ arm_kprobe_decode_insn(kprobe_opcode_t *addr, struct arch_specific_insn *asi) else scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE; } - decoded = arm_probe_decode_insn(insn, &asi->api); if (decoded != INSN_REJECTED && scan_end) if (is_probed_address_atomic(addr - 1, scan_end)) |