From: Karl Mehltretter <kmehltretter@gmail.com>
To: Kees Cook <kees@kernel.org>
Cc: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
"Linus Walleij" <linusw@kernel.org>,
"Nathan Chancellor" <nathan@kernel.org>,
"Sami Tolvanen" <samitolvanen@google.com>,
"Zhen Lei" <thunder.leizhen@huawei.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Michał Pecio" <michal.pecio@gmail.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
"Russell King" <linux@armlinux.org.uk>,
"Will Deacon" <will@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Bill Wendling" <morbo@google.com>,
"Justin Stitt" <justinstitt@google.com>,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v3] ARM: traps: Implement KCFI trap handler for ARM32
Date: Mon, 27 Jul 2026 02:10:19 +0200 [thread overview]
Message-ID: <amafzynVg0_hlOZN@gmail.com> (raw)
In-Reply-To: <20260715175223.make.153-kees@kernel.org>
On Wed, Jul 15, 2026 at 10:52:27AM +0100, Kees Cook wrote:
> +bool arm_cfi_handle_failure(struct pt_regs *regs, enum bug_trap_type type)
> +{
> + switch (type) {
> + case BUG_TRAP_TYPE_BUG:
> + die("Oops - CFI", regs, 0);
> + break;
> + case BUG_TRAP_TYPE_WARN:
> + /* Permissive mode: skip the trapping instruction and continue. */
> + instruction_pointer(regs) += 4;
> + break;
On Thumb-2, Clang emits a 16-bit BKPT for CFI checks.
This skips the following Thumb instruction.
Thanks,
Karl
next prev parent reply other threads:[~2026-07-27 0:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-15 17:52 [PATCH v3] ARM: traps: Implement KCFI trap handler for ARM32 Kees Cook
2026-07-21 0:11 ` Nathan Chancellor
2026-07-21 7:54 ` Linus Walleij
2026-07-21 16:15 ` Nick Desaulniers
2026-07-27 0:10 ` Karl Mehltretter [this message]
2026-07-27 1:28 ` Karl Mehltretter
2026-07-27 1:37 ` Karl Mehltretter
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