From: Borislav Petkov <bp@alien8.de>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>,
"H . Peter Anvin" <hpa@zytor.com>, Joerg Roedel <jroedel@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
"Gustavo A . R . Silva" <gustavoars@kernel.org>,
Jann Horn <jannh@google.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/3] x86/uprobes: Fix not using prefixes.nbytes for loop over prefixes.bytes
Date: Fri, 4 Dec 2020 16:05:22 +0100 [thread overview]
Message-ID: <20201204150522.GG31534@zn.tnic> (raw)
In-Reply-To: <160707931985.3296595.4852247459424743502.stgit@devnote2>
On Fri, Dec 04, 2020 at 07:55:20PM +0900, Masami Hiramatsu wrote:
> +/**
> + * for_each_insn_prefix() -- Iterate prefixes in the instruction
> + * @insn: Pointer to struct insn.
> + * @idx: Index storage.
> + * @prefix: Prefix byte.
> + *
> + * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix
> + * and the index is stored in @idx (note that this @idx is just for a cursor,
> + * do not change it.)
> + * Since prefixes.nbytes can be bigger than NUM_INSN_FIELD_BYTES when some
> + * prefixes are repeated, it can not be used for looping over the prefixes.
> + */
> +#define for_each_insn_prefix(insn, idx, prefix) \
> + for (idx = 0; \
> + idx < MAX_LEGACY_PREFIX_GROUPS && \
The problem I see here is that you check for the index limit to be
< MAX_LEGACY_PREFIX_GROUPS but the array itself is defined using
NUM_INSN_FIELD_BYTES, and that is confusing.
I guess this should be:
#define MAX_LEGACY_PREFIX_GROUPS 4
#define NUM_INSN_FIELD_BYTES MAX_LEGACY_PREFIX_GROUPS
and later, iff the legacy prefixes array size needs separating from the
insn field array size, then the defines would need to change too.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-12-04 15:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 10:55 [PATCH v3 0/3] x86/insn: Fix not using prefixes.nbytes for loop over prefixes.bytes Masami Hiramatsu
2020-12-04 10:55 ` [PATCH v3 1/3] x86/uprobes: " Masami Hiramatsu
2020-12-04 15:05 ` Borislav Petkov [this message]
2020-12-05 0:10 ` Masami Hiramatsu
2020-12-05 10:14 ` Borislav Petkov
2020-12-04 10:55 ` [PATCH v3 2/3] x86/insn-eval: " Masami Hiramatsu
2020-12-04 10:55 ` [PATCH v3 3/3] x86/sev-es: " Masami Hiramatsu
2020-12-04 15:02 ` [PATCH v3 0/3] x86/insn: " Borislav Petkov
2020-12-05 0:22 ` Masami Hiramatsu
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