From: Josh Poimboeuf <jpoimboe@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
"Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Suleiman Souhlal <suleiman@google.com>, bpf <bpf@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@suse.de>,
X86 ML <x86@kernel.org>
Subject: Re: [PATCH] x86,retpoline: Be sure to emit INT3 after JMP *%\reg
Date: Fri, 9 Sep 2022 09:48:09 -0700 [thread overview]
Message-ID: <20220909164809.k5vkeujwpvywkpmt@treble> (raw)
In-Reply-To: <Yxr2TaWaN8VjJ60D@hirez.programming.kicks-ass.net>
On Fri, Sep 09, 2022 at 10:16:13AM +0200, Peter Zijlstra wrote:
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -419,7 +419,9 @@ static void emit_indirect_jump(u8 **ppro
> OPTIMIZER_HIDE_VAR(reg);
> emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip);
> } else {
> - EMIT2(0xFF, 0xE0 + reg);
> + EMIT2(0xFF, 0xE0 + reg); /* jmp *%\reg */
> + if (IS_ENABLED(CONFIG_RETPOLINE) || IS_ENABLED(CONFIG_SLS))
> + EMIT1(0xCC); /* int3 */
> }
Hm, if you have retpolines disabled at runtime, why would you want this.
--
Josh
next prev parent reply other threads:[~2022-09-09 16:49 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 1:34 [PATCH v2 0/2] x86/kprobes: Fixes for CONFIG_RETHUNK Masami Hiramatsu (Google)
2022-09-08 1:34 ` [PATCH v2 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK Masami Hiramatsu (Google)
2022-09-08 5:08 ` Josh Poimboeuf
2022-09-08 9:30 ` Peter Zijlstra
2022-09-08 10:04 ` [PATCH] x86,retpoline: Be sure to emit INT3 after JMP *%\reg Peter Zijlstra
2022-09-08 14:01 ` Alexei Starovoitov
2022-09-09 8:16 ` Peter Zijlstra
2022-09-09 14:19 ` Alexei Starovoitov
2022-09-09 16:48 ` Josh Poimboeuf [this message]
2022-09-11 15:14 ` Peter Zijlstra
2022-09-08 10:08 ` [PATCH v2 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK Peter Zijlstra
2022-09-08 13:03 ` Masami Hiramatsu
2022-09-08 15:01 ` [PATCH v3 0/2] x86/kprobes: Fixes for CONFIG_RETHUNK Masami Hiramatsu (Google)
2022-09-08 15:01 ` [PATCH v3 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK Masami Hiramatsu (Google)
2022-09-08 15:01 ` [PATCH v3 2/2] x86/kprobes: Fix optprobe optimization " Masami Hiramatsu (Google)
2022-12-15 3:31 ` Nadav Amit
2022-12-18 14:28 ` Masami Hiramatsu
2022-09-08 19:31 ` [PATCH v3 0/2] x86/kprobes: Fixes for CONFIG_RETHUNK Josh Poimboeuf
2022-09-08 1:34 ` [PATCH v2 2/2] x86/kprobes: Fix optprobe optimization check with CONFIG_RETHUNK Masami Hiramatsu (Google)
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