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Peter Anvin" , Peter Zijlstra , Xin Li Cc: linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, Jinghao Jia Subject: [PATCH v2 1/3] x86/kprobes: Refactor can_{probe,boost} return type to bool Date: Sat, 3 Feb 2024 21:12:58 -0600 Message-ID: <20240204031300.830475-2-jinghao7@illinois.edu> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240204031300.830475-1-jinghao7@illinois.edu> References: <20240204031300.830475-1-jinghao7@illinois.edu> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-GUID: BvmB3QU77cDUQOBIJkGSbqBZkiK1PtJh X-Proofpoint-ORIG-GUID: oTAYOSqsYwSJlP7N4HcTMSh_KAGAJsTs X-Spam-Details: rule=cautious_plus_nq_notspam policy=cautious_plus_nq score=0 lowpriorityscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 impostorscore=0 mlxscore=0 suspectscore=0 mlxlogscore=999 priorityscore=1501 adultscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2402040022 X-Spam-Score: 0 X-Spam-OrigSender: jinghao7@illinois.edu X-Spam-Bar: Both can_probe and can_boost have int return type but are using int as boolean in their context. Refactor both functions to make them actually return boolean. Signed-off-by: Jinghao Jia Acked-by: Masami Hiramatsu (Google) --- arch/x86/kernel/kprobes/common.h | 2 +- arch/x86/kernel/kprobes/core.c | 33 +++++++++++++++----------------- 2 files changed, 16 insertions(+), 19 deletions(-) diff --git a/arch/x86/kernel/kprobes/common.h b/arch/x86/kernel/kprobes/common.h index c993521d4933..e772276f5aa9 100644 --- a/arch/x86/kernel/kprobes/common.h +++ b/arch/x86/kernel/kprobes/common.h @@ -78,7 +78,7 @@ #endif /* Ensure if the instruction can be boostable */ -extern int can_boost(struct insn *insn, void *orig_addr); +extern bool can_boost(struct insn *insn, void *orig_addr); /* Recover instruction if given address is probed */ extern unsigned long recover_probed_instruction(kprobe_opcode_t *buf, unsigned long addr); diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index e8babebad7b8..644d416441fb 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -137,14 +137,14 @@ NOKPROBE_SYMBOL(synthesize_relcall); * Returns non-zero if INSN is boostable. * RIP relative instructions are adjusted at copying time in 64 bits mode */ -int can_boost(struct insn *insn, void *addr) +bool can_boost(struct insn *insn, void *addr) { kprobe_opcode_t opcode; insn_byte_t prefix; int i; if (search_exception_tables((unsigned long)addr)) - return 0; /* Page fault may occur on this address. */ + return false; /* Page fault may occur on this address. */ /* 2nd-byte opcode */ if (insn->opcode.nbytes == 2) @@ -152,7 +152,7 @@ int can_boost(struct insn *insn, void *addr) (unsigned long *)twobyte_is_boostable); if (insn->opcode.nbytes != 1) - return 0; + return false; for_each_insn_prefix(insn, i, prefix) { insn_attr_t attr; @@ -160,7 +160,7 @@ int can_boost(struct insn *insn, void *addr) attr = inat_get_opcode_attribute(prefix); /* Can't boost Address-size override prefix and CS override prefix */ if (prefix == 0x2e || inat_is_address_size_prefix(attr)) - return 0; + return false; } opcode = insn->opcode.bytes[0]; @@ -181,12 +181,12 @@ int can_boost(struct insn *insn, void *addr) case 0xf6 ... 0xf7: /* Grp3 */ case 0xfe: /* Grp4 */ /* ... are not boostable */ - return 0; + return false; case 0xff: /* Grp5 */ /* Only indirect jmp is boostable */ return X86_MODRM_REG(insn->modrm.bytes[0]) == 4; default: - return 1; + return true; } } @@ -253,20 +253,18 @@ unsigned long recover_probed_instruction(kprobe_opcode_t *buf, unsigned long add } /* Check if paddr is at an instruction boundary */ -static int can_probe(unsigned long paddr) +static bool can_probe(unsigned long paddr) { unsigned long addr, __addr, offset = 0; struct insn insn; kprobe_opcode_t buf[MAX_INSN_SIZE]; if (!kallsyms_lookup_size_offset(paddr, NULL, &offset)) - return 0; + return false; /* Decode instructions */ addr = paddr - offset; while (addr < paddr) { - int ret; - /* * Check if the instruction has been modified by another * kprobe, in which case we replace the breakpoint by the @@ -277,11 +275,10 @@ static int can_probe(unsigned long paddr) */ __addr = recover_probed_instruction(buf, addr); if (!__addr) - return 0; + return false; - ret = insn_decode_kernel(&insn, (void *)__addr); - if (ret < 0) - return 0; + if (insn_decode_kernel(&insn, (void *)__addr) < 0) + return false; #ifdef CONFIG_KGDB /* @@ -290,7 +287,7 @@ static int can_probe(unsigned long paddr) */ if (insn.opcode.bytes[0] == INT3_INSN_OPCODE && kgdb_has_hit_break(addr)) - return 0; + return false; #endif addr += insn.length; } @@ -310,10 +307,10 @@ static int can_probe(unsigned long paddr) */ __addr = recover_probed_instruction(buf, addr); if (!__addr) - return 0; + return false; if (insn_decode_kernel(&insn, (void *)__addr) < 0) - return 0; + return false; if (insn.opcode.value == 0xBA) offset = 12; @@ -324,7 +321,7 @@ static int can_probe(unsigned long paddr) /* This movl/addl is used for decoding CFI. */ if (is_cfi_trap(addr + offset)) - return 0; + return false; } out: