From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A92EC433E0 for ; Thu, 30 Jul 2020 12:29:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6058F2082E for ; Thu, 30 Jul 2020 12:29:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="WSj5RPMJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728892AbgG3M3J (ORCPT ); Thu, 30 Jul 2020 08:29:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728224AbgG3M3G (ORCPT ); Thu, 30 Jul 2020 08:29:06 -0400 Received: from mail-qk1-x744.google.com (mail-qk1-x744.google.com [IPv6:2607:f8b0:4864:20::744]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51D10C0619D4 for ; Thu, 30 Jul 2020 05:29:04 -0700 (PDT) Received: by mail-qk1-x744.google.com with SMTP id 11so25386539qkn.2 for ; Thu, 30 Jul 2020 05:29:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=a9jZH6Ll+sEH5WFMFRXAZ0o9TX5SDfud55CbQYcvoaA=; b=WSj5RPMJbQFYGXKFa57Tt+1uPT5FuT5rpSK8NNCi9wwgIMbSj0cdw0haGQ+8Pcc9Qe dg0s35Nr8WipD1fDqaycqfRTfRYaUSLSNg1xHVWXbk4HeNwAEqLnxquDP24Imbk3gdfc ZUUmg1QaWMBy4qV6M7SNEDwwMG6nUcjtUPZ8YJWXAPmMbFYX3FypuDhVEad1lccx+T5H yBMguWxzxZ1flfBGjdFG1kwZOApBkSk7556CwptBg9W1mNKWlJ8xSs2YP8CWp7pbnWGp QOIpWQORAgijBiOZblNHDMwVZTM14QvSL39XQmVsNxa1VPiz6E2x0SpxLIVFMlDyEyAs 4W/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=a9jZH6Ll+sEH5WFMFRXAZ0o9TX5SDfud55CbQYcvoaA=; b=e3AQ0ZR+TV97n9NmqGzqTUANCJwkjW3CMXeaTpv+XznG4j9sOqcEboQJ9yn7CeOYHt u7sHRbvw2OBuvty27+11hBv0QIAcAgz1RlIqmZpMkiFiqjjzFuwYOJbzR0zC9bfPYcSM 1nq7Pj4jzJxAjfLu6sX2PQiG5Xg6gz+MozTmj71/GWte7Eiv5HtReRJQXoNxJScxs9MM xQQICBhNAyLUqNfVYJDiGQnHrjufsQIdQVx8UWgIimNWZSFv4qcwkJ7cvDD6znwIS7Ch mAnbjd7hREBkxb7rnYuUCG6U2UOesyLp2FfIq4OItVsn5lXKbs0eMvT9ZRW5AeNkmLIV IThQ== X-Gm-Message-State: AOAM533wNIhMIJWiNUUoL2D6JfCTmsAyWl0AresMn+wOuQkqpIz5L+Nr /nTmSaLPb7Ngg753rjKAOVYncg== X-Google-Smtp-Source: ABdhPJwSdsCtQ0DJ9ivSf+lIOXepWUFKgPioDAv68OAiCRuMu9agvZzMQmfas/iKby0HEJZ0V8rCqA== X-Received: by 2002:a37:a45:: with SMTP id 66mr39219924qkk.435.1596112143280; Thu, 30 Jul 2020 05:29:03 -0700 (PDT) Received: from lca.pw (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id b8sm4129626qtg.45.2020.07.30.05.29.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jul 2020 05:29:02 -0700 (PDT) Date: Thu, 30 Jul 2020 08:28:56 -0400 From: Qian Cai To: Jean-Philippe Brucker Cc: linux-arm-kernel@lists.infradead.org, bpf@vger.kernel.org, songliubraving@fb.com, andriin@fb.com, daniel@iogearbox.net, catalin.marinas@arm.com, john.fastabend@gmail.com, ast@kernel.org, zlim.lnx@gmail.com, kpsingh@chromium.org, yhs@fb.com, will@kernel.org, kafai@fb.com, sfr@canb.auug.org.au, linux-next@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH bpf-next 1/1] arm64: bpf: Add BPF exception tables Message-ID: <20200730122855.GA3773@lca.pw> References: <20200728152122.1292756-1-jean-philippe@linaro.org> <20200728152122.1292756-2-jean-philippe@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200728152122.1292756-2-jean-philippe@linaro.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 28, 2020 at 05:21:26PM +0200, Jean-Philippe Brucker wrote: > When a tracing BPF program attempts to read memory without using the > bpf_probe_read() helper, the verifier marks the load instruction with > the BPF_PROBE_MEM flag. Since the arm64 JIT does not currently recognize > this flag it falls back to the interpreter. > > Add support for BPF_PROBE_MEM, by appending an exception table to the > BPF program. If the load instruction causes a data abort, the fixup > infrastructure finds the exception table and fixes up the fault, by > clearing the destination register and jumping over the faulting > instruction. > > To keep the compact exception table entry format, inspect the pc in > fixup_exception(). A more generic solution would add a "handler" field > to the table entry, like on x86 and s390. > > Signed-off-by: Jean-Philippe Brucker This will fail to compile on arm64, https://gitlab.com/cailca/linux-mm/-/blob/master/arm64.config arch/arm64/mm/extable.o: In function `fixup_exception': arch/arm64/mm/extable.c:19: undefined reference to `arm64_bpf_fixup_exception' > --- > Note: the extable is aligned on 32 bits. Given that extable entries have > 32-bit members I figured we don't need to align it to 64 bits. > --- > arch/arm64/include/asm/extable.h | 3 ++ > arch/arm64/mm/extable.c | 11 ++-- > arch/arm64/net/bpf_jit_comp.c | 93 +++++++++++++++++++++++++++++--- > 3 files changed, 98 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/extable.h b/arch/arm64/include/asm/extable.h > index 56a4f68b262e..bcee40df1586 100644 > --- a/arch/arm64/include/asm/extable.h > +++ b/arch/arm64/include/asm/extable.h > @@ -22,5 +22,8 @@ struct exception_table_entry > > #define ARCH_HAS_RELATIVE_EXTABLE > > +int arm64_bpf_fixup_exception(const struct exception_table_entry *ex, > + struct pt_regs *regs); > + > extern int fixup_exception(struct pt_regs *regs); > #endif > diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c > index 81e694af5f8c..1f42991cacdd 100644 > --- a/arch/arm64/mm/extable.c > +++ b/arch/arm64/mm/extable.c > @@ -11,8 +11,13 @@ int fixup_exception(struct pt_regs *regs) > const struct exception_table_entry *fixup; > > fixup = search_exception_tables(instruction_pointer(regs)); > - if (fixup) > - regs->pc = (unsigned long)&fixup->fixup + fixup->fixup; > + if (!fixup) > + return 0; > > - return fixup != NULL; > + if (regs->pc >= BPF_JIT_REGION_START && > + regs->pc < BPF_JIT_REGION_END) > + return arm64_bpf_fixup_exception(fixup, regs); > + > + regs->pc = (unsigned long)&fixup->fixup + fixup->fixup; > + return 1; > } > diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c > index 3cb25b43b368..f8912e45be7a 100644 > --- a/arch/arm64/net/bpf_jit_comp.c > +++ b/arch/arm64/net/bpf_jit_comp.c > @@ -7,6 +7,7 @@ > > #define pr_fmt(fmt) "bpf_jit: " fmt > > +#include > #include > #include > #include > @@ -56,6 +57,7 @@ struct jit_ctx { > int idx; > int epilogue_offset; > int *offset; > + int exentry_idx; > __le32 *image; > u32 stack_size; > }; > @@ -351,6 +353,67 @@ static void build_epilogue(struct jit_ctx *ctx) > emit(A64_RET(A64_LR), ctx); > } > > +#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0) > +#define BPF_FIXUP_REG_MASK GENMASK(31, 27) > + > +int arm64_bpf_fixup_exception(const struct exception_table_entry *ex, > + struct pt_regs *regs) > +{ > + off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup); > + int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup); > + > + regs->regs[dst_reg] = 0; > + regs->pc = (unsigned long)&ex->fixup - offset; > + return 1; > +} > + [] From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5CC60C433E1 for ; Thu, 30 Jul 2020 12:31:05 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2EA3D2074B for ; Thu, 30 Jul 2020 12:31:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="tbFLKr+0"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="WSj5RPMJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2EA3D2074B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NhlRuhkdpmLgxbXwMSvXEPRLFQUAFpwMiBAsCApErYQ=; b=tbFLKr+0zHeCmNGAZK7RO/UZF PrxfwMBKvLkOlS0TGrDsMD8uSBQmNjJ0mW25xL1ednkz5n6LKA/wS9nJ/ts7RWrz0y6OHwtAEcL1O CgdGD0A8iio/8e7WA/O8f05juKuw6UOORD+3nu6UUxdnc5nvmwgce5t9K9egvLSaaMXJC7ttkPMHl Ep4Hwl1MiBhVVfyj1kHAtwS9MhuOGcEjRuARLlQPbXq2Yzg3k+DkHPTTjSLqs3pwFgf6/0ARZ9ju1 NnKOJyJVg51lMRV9fkTvHWsal/yIA3LmkqJ3H1P2OomJ0q92N2BDI5snJQemcDKHRocL22zG1FJwF jhR3dL4/g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k17gM-0003l7-20; Thu, 30 Jul 2020 12:29:10 +0000 Received: from mail-qk1-x742.google.com ([2607:f8b0:4864:20::742]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k17gI-0003jr-SJ for linux-arm-kernel@lists.infradead.org; Thu, 30 Jul 2020 12:29:07 +0000 Received: by mail-qk1-x742.google.com with SMTP id 2so21231752qkf.10 for ; Thu, 30 Jul 2020 05:29:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=a9jZH6Ll+sEH5WFMFRXAZ0o9TX5SDfud55CbQYcvoaA=; b=WSj5RPMJbQFYGXKFa57Tt+1uPT5FuT5rpSK8NNCi9wwgIMbSj0cdw0haGQ+8Pcc9Qe dg0s35Nr8WipD1fDqaycqfRTfRYaUSLSNg1xHVWXbk4HeNwAEqLnxquDP24Imbk3gdfc ZUUmg1QaWMBy4qV6M7SNEDwwMG6nUcjtUPZ8YJWXAPmMbFYX3FypuDhVEad1lccx+T5H yBMguWxzxZ1flfBGjdFG1kwZOApBkSk7556CwptBg9W1mNKWlJ8xSs2YP8CWp7pbnWGp QOIpWQORAgijBiOZblNHDMwVZTM14QvSL39XQmVsNxa1VPiz6E2x0SpxLIVFMlDyEyAs 4W/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=a9jZH6Ll+sEH5WFMFRXAZ0o9TX5SDfud55CbQYcvoaA=; b=lhyLIYLpdT4rYAoJiRwDAwPaPkJMmHVztrf2yrI7bbK3hvr0Cw5ORLB1pJQLxeaZRJ wuspNZwcIaWT0t6bLvYIwWqWbHCTdC52WYpi1F6wDATHx7AtIvMoqNzAb3iFf8B2AhFj 8fDSih1W1Rlf7KQeRz4l2NAcIoXdjwJhOb6odZgudDuxE/zJ/KudqA6OesKu2O2ZX/L1 lUJL7a+d8pbuRISWWCdSX9zSA8HvZMeig3q22oOLU6vZ0E2eDlR6BxFHjE8DL/XJKBVJ 0Y2/YVm6s3o4prPPnkQ/a7csDG/QTCmdEjvHlXa/ZAf1wMNbZARNVlm5/5b1CRaAiyFG P0nw== X-Gm-Message-State: AOAM530Y01U2v1uYd+/BrR+yyAmtU8dNGdI6Gtwfz0ahEk1f/oakSfru ChEwDiSSbOqrBI/Pa6tx3tUvIw== X-Google-Smtp-Source: ABdhPJwSdsCtQ0DJ9ivSf+lIOXepWUFKgPioDAv68OAiCRuMu9agvZzMQmfas/iKby0HEJZ0V8rCqA== X-Received: by 2002:a37:a45:: with SMTP id 66mr39219924qkk.435.1596112143280; Thu, 30 Jul 2020 05:29:03 -0700 (PDT) Received: from lca.pw (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id b8sm4129626qtg.45.2020.07.30.05.29.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jul 2020 05:29:02 -0700 (PDT) Date: Thu, 30 Jul 2020 08:28:56 -0400 From: Qian Cai To: Jean-Philippe Brucker Subject: Re: [PATCH bpf-next 1/1] arm64: bpf: Add BPF exception tables Message-ID: <20200730122855.GA3773@lca.pw> References: <20200728152122.1292756-1-jean-philippe@linaro.org> <20200728152122.1292756-2-jean-philippe@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200728152122.1292756-2-jean-philippe@linaro.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200730_082907_029859_09C2C7C5 X-CRM114-Status: GOOD ( 26.62 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sfr@canb.auug.org.au, songliubraving@fb.com, daniel@iogearbox.net, catalin.marinas@arm.com, john.fastabend@gmail.com, ast@kernel.org, linux-kernel@vger.kernel.org, will@kernel.org, linux-next@vger.kernel.org, zlim.lnx@gmail.com, kpsingh@chromium.org, yhs@fb.com, bpf@vger.kernel.org, andriin@fb.com, kafai@fb.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jul 28, 2020 at 05:21:26PM +0200, Jean-Philippe Brucker wrote: > When a tracing BPF program attempts to read memory without using the > bpf_probe_read() helper, the verifier marks the load instruction with > the BPF_PROBE_MEM flag. Since the arm64 JIT does not currently recognize > this flag it falls back to the interpreter. > > Add support for BPF_PROBE_MEM, by appending an exception table to the > BPF program. If the load instruction causes a data abort, the fixup > infrastructure finds the exception table and fixes up the fault, by > clearing the destination register and jumping over the faulting > instruction. > > To keep the compact exception table entry format, inspect the pc in > fixup_exception(). A more generic solution would add a "handler" field > to the table entry, like on x86 and s390. > > Signed-off-by: Jean-Philippe Brucker This will fail to compile on arm64, https://gitlab.com/cailca/linux-mm/-/blob/master/arm64.config arch/arm64/mm/extable.o: In function `fixup_exception': arch/arm64/mm/extable.c:19: undefined reference to `arm64_bpf_fixup_exception' > --- > Note: the extable is aligned on 32 bits. Given that extable entries have > 32-bit members I figured we don't need to align it to 64 bits. > --- > arch/arm64/include/asm/extable.h | 3 ++ > arch/arm64/mm/extable.c | 11 ++-- > arch/arm64/net/bpf_jit_comp.c | 93 +++++++++++++++++++++++++++++--- > 3 files changed, 98 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/extable.h b/arch/arm64/include/asm/extable.h > index 56a4f68b262e..bcee40df1586 100644 > --- a/arch/arm64/include/asm/extable.h > +++ b/arch/arm64/include/asm/extable.h > @@ -22,5 +22,8 @@ struct exception_table_entry > > #define ARCH_HAS_RELATIVE_EXTABLE > > +int arm64_bpf_fixup_exception(const struct exception_table_entry *ex, > + struct pt_regs *regs); > + > extern int fixup_exception(struct pt_regs *regs); > #endif > diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c > index 81e694af5f8c..1f42991cacdd 100644 > --- a/arch/arm64/mm/extable.c > +++ b/arch/arm64/mm/extable.c > @@ -11,8 +11,13 @@ int fixup_exception(struct pt_regs *regs) > const struct exception_table_entry *fixup; > > fixup = search_exception_tables(instruction_pointer(regs)); > - if (fixup) > - regs->pc = (unsigned long)&fixup->fixup + fixup->fixup; > + if (!fixup) > + return 0; > > - return fixup != NULL; > + if (regs->pc >= BPF_JIT_REGION_START && > + regs->pc < BPF_JIT_REGION_END) > + return arm64_bpf_fixup_exception(fixup, regs); > + > + regs->pc = (unsigned long)&fixup->fixup + fixup->fixup; > + return 1; > } > diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c > index 3cb25b43b368..f8912e45be7a 100644 > --- a/arch/arm64/net/bpf_jit_comp.c > +++ b/arch/arm64/net/bpf_jit_comp.c > @@ -7,6 +7,7 @@ > > #define pr_fmt(fmt) "bpf_jit: " fmt > > +#include > #include > #include > #include > @@ -56,6 +57,7 @@ struct jit_ctx { > int idx; > int epilogue_offset; > int *offset; > + int exentry_idx; > __le32 *image; > u32 stack_size; > }; > @@ -351,6 +353,67 @@ static void build_epilogue(struct jit_ctx *ctx) > emit(A64_RET(A64_LR), ctx); > } > > +#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0) > +#define BPF_FIXUP_REG_MASK GENMASK(31, 27) > + > +int arm64_bpf_fixup_exception(const struct exception_table_entry *ex, > + struct pt_regs *regs) > +{ > + off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup); > + int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup); > + > + regs->regs[dst_reg] = 0; > + regs->pc = (unsigned long)&ex->fixup - offset; > + return 1; > +} > + [] _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel