linux-kernel - [PATCH v3 2/4] arm64: kprobes: Remove unneeded RODATA check

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Date:   Wed, 13 Feb 2019 00:43:51 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        Pratyush Anand <panand@...hat.com>,
        "David A . Long" <dave.long@...aro.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        James Morse <james.morse@....com>
Subject: [PATCH v3 2/4] arm64: kprobes: Remove unneeded RODATA check

Remove unneeded RODATA check from arch_prepare_kprobe().

Since check_kprobe_address_safe() already ensured that
the probe address is in kernel text, we don't need to
check whether the address in RODATA or not. That must
be always false.

Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 arch/arm64/kernel/probes/kprobes.c |    6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 9989ec9baa11..bd06b4b13fa9 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -91,8 +91,6 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
 	unsigned long probe_addr = (unsigned long)p->addr;
-	extern char __start_rodata[];
-	extern char __end_rodata[];
 
 	if (probe_addr & 0x3)
 		return -EINVAL;
@@ -106,10 +104,6 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	if (search_exception_tables(probe_addr))
 		return -EINVAL;
 
-	if (probe_addr >= (unsigned long) __start_rodata &&
-	    probe_addr <= (unsigned long) __end_rodata)
-		return -EINVAL;
-
 	/* decode instruction */
 	switch (arm_kprobe_decode_insn(p->addr, &p->ainsn)) {
 	case INSN_REJECTED:	/* insn not supported */