From patchwork Fri Jun 1 11:24:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 137523 Delivered-To: patch@linaro.org Received: by 2002:a2e:9706:0:0:0:0:0 with SMTP id r6-v6csp808638lji; Fri, 1 Jun 2018 04:28:44 -0700 (PDT) X-Google-Smtp-Source: ADUXVKJR27icy+ZVksX+xoIbM4j3XjGPVdSVMsaanabNP6npaFsWAaLl1wiqKeEbVd1mEPQwtSfF X-Received: by 2002:a62:7002:: with SMTP id l2-v6mr10584593pfc.40.1527852524139; Fri, 01 Jun 2018 04:28:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1527852524; cv=none; d=google.com; s=arc-20160816; b=IBg1BvGA/iakDwc0O02Fw0uQrCtiY6Js7hiNx/mRWDKPjrWbniQEKA9FJwjBzLOQYp M8S2k06wsOSpvaMrx6hvow+dzsR40WDeUFOdkHc2No5E9VSRHb8gWZTMzrgbZ0QWtx1v Xd/zlKXBa/eCdaSXZxpyBAKt+gbwfZFUQibO42YbP+TdT8cw8J59SmCf3bJommPVaGaS smZ9jw0ZemTwBrpF/HdQT2/O2sFdKiT/uT7cf8Ho3Q40YwqCXpZktNJ7Quxrz0sQrs12 YtPuPsiuN3jedszpun5b1iKB/7zCj0jUgC8DdqNRbAToyodOojr8d7NjGSEhu6qj+5R2 Uq8Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=UTpi8NEWpmi6EFSDxdnqEfECO5z5xFrLIIT14P6puXs=; b=KxhlczKs1bhuA6FjdWdIzTH8RxxB8ItEzd1Xtx2KS/+oL/fUCzmE0quHCAMrVv7exT np9rf2Te8k0PT0uwx3/YYYm2mYizxizYYyI3Qoi2hjkIwwtE71xAarclfnadv6KcnaR/ FpvToBXrHAOyZKW411kxWuxn4jaqGt5jsuiOVucj0eBzYOrU51u1GhFMccV5OTfJfDTY bstBjFWFBGGKfK9LNftcIy25axzwz0U+kU+goMqX+DUdAmIfpVwXcPM1RI0m5/i7xZZY YL25oiMw+D4IKhd9JlfnrJhASaf1Duz3tBUZX9evVqnX4/0NOGLisMWvGTgqjMlLJmgU Wmtg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id b4-v6si31564672pgc.190.2018.06.01.04.28.43; Fri, 01 Jun 2018 04:28:44 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752132AbeFAL2m (ORCPT + 30 others); Fri, 1 Jun 2018 07:28:42 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:50312 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751942AbeFALZF (ORCPT ); Fri, 1 Jun 2018 07:25:05 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6AA991650; Fri, 1 Jun 2018 04:25:05 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5D87B3F25D; Fri, 1 Jun 2018 04:25:04 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will.deacon@arm.com, catalin.marinas@arm.com Cc: Mark Rutland Subject: [PATCHv2 08/19] arm64: convert raw syscall invocation to C Date: Fri, 1 Jun 2018 12:24:30 +0100 Message-Id: <20180601112441.37810-9-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180601112441.37810-1-mark.rutland@arm.com> References: <20180601112441.37810-1-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As a first step towards invoking syscalls with a pt_regs argument, convert the raw syscall invocation logic to C. We end up with a bit more register shuffling, but the unified invocation logic means we can unify the tracing paths, too. Previously, assembly had to open-code calls to ni_sys() when the system call number was out-of-bounds for the relevant syscall table. This case is now handled by invoke_syscall(), and the assembly no longer need to handle this case explicitly. This allows the tracing paths to be simplfiied and unified, as we no longer need the __ni_sys_trace path and the __sys_trace_return label. This only converts the invocation of the syscall. The rest of the syscall triage and tracing is left in assembly for now, and will be converted in subsequent patches. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon --- arch/arm64/kernel/Makefile | 3 ++- arch/arm64/kernel/entry.S | 36 ++++++++++-------------------------- arch/arm64/kernel/syscall.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 42 insertions(+), 27 deletions(-) create mode 100644 arch/arm64/kernel/syscall.c -- 2.11.0 diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 0025f8691046..4e24d2244bd1 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -18,7 +18,8 @@ arm64-obj-y := debug-monitors.o entry.o irq.o fpsimd.o \ hyp-stub.o psci.o cpu_ops.o insn.o \ return_address.o cpuinfo.o cpu_errata.o \ cpufeature.o alternative.o cacheinfo.o \ - smp.o smp_spin_table.o topology.o smccc-call.o + smp.o smp_spin_table.o topology.o smccc-call.o \ + syscall.o extra-$(CONFIG_EFI) := efi-entry.o diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 62f2876f9c63..46543f34b9dc 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -903,7 +903,6 @@ ENDPROC(el0_error) */ ret_fast_syscall: disable_daif - str x0, [sp, #S_X0] // returned x0 ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for syscall tracing and x2, x1, #_TIF_SYSCALL_WORK cbnz x2, ret_fast_syscall_trace @@ -976,15 +975,11 @@ el0_svc_naked: // compat entry point tst x16, #_TIF_SYSCALL_WORK // check for syscall hooks b.ne __sys_trace - cmp wscno, wsc_nr // check upper syscall limit - b.hs ni_sys - mask_nospec64 xscno, xsc_nr, x19 // enforce bounds for syscall number - ldr x16, [stbl, xscno, lsl #3] // address in the syscall table - blr x16 // call sys_* routine - b ret_fast_syscall -ni_sys: mov x0, sp - bl do_ni_syscall + mov w1, wscno + mov w2, wsc_nr + mov x3, stbl + bl invoke_syscall b ret_fast_syscall ENDPROC(el0_svc) @@ -1001,29 +996,18 @@ __sys_trace: bl syscall_trace_enter cmp w0, #NO_SYSCALL // skip the syscall? b.eq __sys_trace_return_skipped - mov wscno, w0 // syscall number (possibly new) - mov x1, sp // pointer to regs - cmp wscno, wsc_nr // check upper syscall limit - b.hs __ni_sys_trace - ldp x0, x1, [sp] // restore the syscall args - ldp x2, x3, [sp, #S_X2] - ldp x4, x5, [sp, #S_X4] - ldp x6, x7, [sp, #S_X6] - ldr x16, [stbl, xscno, lsl #3] // address in the syscall table - blr x16 // call sys_* routine -__sys_trace_return: - str x0, [sp, #S_X0] // save returned x0 + mov x0, sp + mov w1, wscno + mov w2, wsc_nr + mov x3, stbl + bl invoke_syscall + __sys_trace_return_skipped: mov x0, sp bl syscall_trace_exit b ret_to_user -__ni_sys_trace: - mov x0, sp - bl do_ni_syscall - b __sys_trace_return - .popsection // .entry.text #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c new file mode 100644 index 000000000000..b463b962d597 --- /dev/null +++ b/arch/arm64/kernel/syscall.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +long do_ni_syscall(struct pt_regs *regs); + +typedef long (*syscall_fn_t)(unsigned long, unsigned long, + unsigned long, unsigned long, + unsigned long, unsigned long); + +static void __invoke_syscall(struct pt_regs *regs, syscall_fn_t syscall_fn) +{ + regs->regs[0] = syscall_fn(regs->regs[0], regs->regs[1], + regs->regs[2], regs->regs[3], + regs->regs[4], regs->regs[5]); +} + +asmlinkage void invoke_syscall(struct pt_regs *regs, unsigned int scno, + unsigned int sc_nr, + syscall_fn_t syscall_table[]) +{ + if (scno < sc_nr) { + syscall_fn_t syscall_fn; + syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)]; + __invoke_syscall(regs, syscall_fn); + } else { + regs->regs[0] = do_ni_syscall(regs); + } +}