From: Peter Zijlstra <peterz@infradead•org>
To: Ard Biesheuvel <ard.biesheuvel@linaro•org>
Cc: "Jason A . Donenfeld" <Jason@zx2c4•com>,
Catalin Marinas <catalin.marinas@arm•com>,
Will Deacon <will.deacon@arm•com>,
Samuel Neves <sneves@dei•uc.pt>,
Paul Mackerras <paulus@samba•org>,
Herbert Xu <herbert@gondor•apana.org.au>,
Richard Weinberger <richard@nod•at>,
Eric Biggers <ebiggers@kernel•org>,
Ingo Molnar <mingo@redhat•com>, Kees Cook <keescook@chromium•org>,
Arnd Bergmann <arnd@arndb•de>, Andy Lutomirski <luto@kernel•org>,
Thomas Gleixner <tglx@linutronix•de>,
linux-arm-kernel@lists•infradead.org,
"Martin K. Petersen" <martin.petersen@oracle•com>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
linux-kernel@vger•kernel.org, linux-crypto@vger•kernel.org,
Andrew Morton <akpm@linux-foundation•org>,
linuxppc-dev@lists•ozlabs.org,
"David S. Miller" <davem@davemloft•net>
Subject: Re: [RFC PATCH 1/9] kernel: add support for patchable function pointers
Date: Fri, 5 Oct 2018 16:14:33 +0200 [thread overview]
Message-ID: <20181005141433.GS19272@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20181005081333.15018-2-ard.biesheuvel@linaro.org>
On Fri, Oct 05, 2018 at 10:13:25AM +0200, Ard Biesheuvel wrote:
> diff --git a/include/linux/ffp.h b/include/linux/ffp.h
> new file mode 100644
> index 000000000000..8fc3b4c9b38f
> --- /dev/null
> +++ b/include/linux/ffp.h
> @@ -0,0 +1,43 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __LINUX_FFP_H
> +#define __LINUX_FFP_H
> +
> +#include <linux/types.h>
> +#include <linux/compiler.h>
> +
> +#ifdef CONFIG_HAVE_ARCH_FFP
> +#include <asm/ffp.h>
> +#else
> +
> +struct ffp {
> + void (**fn)(void);
> + void (*default_fn)(void);
> +};
> +
> +#define DECLARE_FFP(_fn, _def) \
> + extern typeof(_def) *_fn; \
> + extern struct ffp const __ffp_ ## _fn
> +
> +#define DEFINE_FFP(_fn, _def) \
> + typeof(_def) *_fn = &_def; \
> + struct ffp const __ffp_ ## _fn \
> + = { (void(**)(void))&_fn, (void(*)(void))&_def }; \
> + EXPORT_SYMBOL(__ffp_ ## _fn)
> +
> +static inline void ffp_set_target(const struct ffp *m, void *new_fn)
> +{
> + WRITE_ONCE(*m->fn, new_fn);
> +}
> +
> +static inline void ffp_reset_target(const struct ffp *m)
> +{
> + WRITE_ONCE(*m->fn, m->default_fn);
> +}
> +
> +#endif
> +
> +#define SET_FFP(_fn, _new) ffp_set_target(&__ffp_ ## _fn, _new)
> +#define RESET_FFP(_fn) ffp_reset_target(&__ffp_ ## _fn)
> +
> +#endif
I don't understand this interface. There is no wrapper for the call
site, so how are we going to patch all call-sites when you update the
target?
next prev parent reply other threads:[~2018-10-05 14:17 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-05 8:13 [RFC PATCH 0/9] patchable function pointers for pluggable crypto routines Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 1/9] kernel: add support for patchable function pointers Ard Biesheuvel
2018-10-05 13:57 ` Peter Zijlstra
2018-10-05 14:03 ` Ard Biesheuvel
2018-10-05 14:14 ` Peter Zijlstra [this message]
2018-10-05 14:57 ` Ard Biesheuvel
2018-10-05 15:08 ` Andy Lutomirski
2018-10-05 15:24 ` Ard Biesheuvel
2018-10-05 16:58 ` Andy Lutomirski
2018-10-05 17:11 ` Ard Biesheuvel
2018-10-05 17:20 ` Andy Lutomirski
2018-10-05 17:23 ` Ard Biesheuvel
2018-10-05 17:28 ` Andy Lutomirski
2018-10-05 17:37 ` Jason A. Donenfeld
2018-10-05 17:44 ` Andy Lutomirski
2018-10-05 18:28 ` Jason A. Donenfeld
2018-10-05 19:13 ` Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 2/9] arm64: kernel: add arch " Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 3/9] crypto: crc-t10dif - make crc_t10dif a static inline Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 4/9] crypto: crc-t10dif - use patchable function pointer for core update routine Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 5/9] crypto: crc-t10dif/arm64 - move PMULL based code into core library Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 6/9] crypto: crc-t10dif/arm " Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 7/9] crypto: crct10dif/generic - switch crypto API driver to " Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 8/9] crypto: crc-t10dif/powerpc - move PMULL based code into " Ard Biesheuvel
2018-10-05 8:13 ` [RFC PATCH 9/9] crypto: crc-t10dif/x86 " Ard Biesheuvel
2018-10-05 13:37 ` [RFC PATCH 0/9] patchable function pointers for pluggable crypto routines Jason A. Donenfeld
2018-10-05 17:15 ` Ard Biesheuvel
2018-10-05 17:26 ` Andy Lutomirski
2018-10-05 17:28 ` Ard Biesheuvel
2018-10-05 18:00 ` Andy Lutomirski
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