From: Christoph Hellwig <hch@infradead.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Kees Cook <keescook@chromium.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
bpf@vger.kernel.org, linux-hardening@vger.kernel.org,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 03/17] mm: add generic __va_function and __pa_function macros
Date: Wed, 24 Mar 2021 07:13:57 +0000 [thread overview]
Message-ID: <20210324071357.GB2639075@infradead.org> (raw)
In-Reply-To: <20210323203946.2159693-4-samitolvanen@google.com>
On Tue, Mar 23, 2021 at 01:39:32PM -0700, Sami Tolvanen wrote:
> With CONFIG_CFI_CLANG, the compiler replaces function addresses
> in instrumented C code with jump table addresses. This means that
> __pa_symbol(function) returns the physical address of the jump table
> entry instead of the actual function, which may not work as the jump
> table code will immediately jump to a virtual address that may not be
> mapped.
>
> To avoid this address space confusion, this change adds generic
> definitions for __va_function and __pa_function, which architectures
> that support CFI can override. The typical implementation of the
> __va_function macro would use inline assembly to take the function
> address, which avoids compiler instrumentation.
I think these helper are sensible, but shouldn't they have somewhat
less arcane names and proper documentation?
next prev parent reply other threads:[~2021-03-24 7:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 20:39 [PATCH v3 00/17] Add support for Clang CFI Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 01/17] add " Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 02/17] cfi: add __cficanonical Sami Tolvanen
2021-03-24 15:31 ` Rasmus Villemoes
2021-03-24 16:38 ` Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 03/17] mm: add generic __va_function and __pa_function macros Sami Tolvanen
2021-03-24 7:13 ` Christoph Hellwig [this message]
2021-03-24 15:54 ` Sami Tolvanen
2021-03-25 10:16 ` Mark Rutland
2021-03-25 23:17 ` Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 04/17] module: ensure __cfi_check alignment Sami Tolvanen
2021-03-26 4:34 ` Kees Cook
2021-03-29 9:26 ` Jessica Yu
2021-03-23 20:39 ` [PATCH v3 05/17] workqueue: use WARN_ON_FUNCTION_MISMATCH Sami Tolvanen
2021-03-26 4:34 ` Kees Cook
2021-03-23 20:39 ` [PATCH v3 06/17] kthread: " Sami Tolvanen
2021-03-26 4:35 ` Kees Cook
2021-03-23 20:39 ` [PATCH v3 07/17] kallsyms: strip ThinLTO hashes from static functions Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 08/17] bpf: disable CFI in dispatcher functions Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 09/17] treewide: Change list_sort to use const pointers Sami Tolvanen
2021-03-23 21:28 ` Nick Desaulniers
2021-03-24 7:10 ` Christoph Hellwig
2021-03-26 4:35 ` Kees Cook
2021-03-23 20:39 ` [PATCH v3 10/17] lkdtm: use __va_function Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 11/17] psci: use __pa_function for cpu_resume Sami Tolvanen
2021-03-25 10:23 ` Mark Rutland
2021-03-23 20:39 ` [PATCH v3 12/17] arm64: implement __va_function Sami Tolvanen
2021-03-25 10:37 ` Mark Rutland
2021-03-25 23:27 ` Sami Tolvanen
2021-03-26 0:03 ` Peter Collingbourne
2021-03-23 20:39 ` [PATCH v3 13/17] arm64: use __pa_function Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 14/17] arm64: add __nocfi to functions that jump to a physical address Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 15/17] arm64: add __nocfi to __apply_alternatives Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 16/17] KVM: arm64: Disable CFI for nVHE Sami Tolvanen
2021-03-23 20:39 ` [PATCH v3 17/17] arm64: allow CONFIG_CFI_CLANG to be selected Sami Tolvanen
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