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[209.132.180.67]) by mx.google.com with ESMTP id b9-v6si7498080pgw.394.2018.05.14.02.47.54; Mon, 14 May 2018 02:47:54 -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 S1752579AbeENJrs (ORCPT + 29 others); Mon, 14 May 2018 05:47:48 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:38276 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752497AbeENJrn (ORCPT ); Mon, 14 May 2018 05:47:43 -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 DB4E0168F; Mon, 14 May 2018 02:47:42 -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 EE3463F25D; Mon, 14 May 2018 02:47:40 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com, dave.martin@arm.com, james.morse@arm.com, linux@dominikbrodowski.net, linux-fsdevel@vger.kernel.org, marc.zyngier@arm.com, mark.rutland@arm.com, viro@zeniv.linux.org.uk, will.deacon@arm.com Subject: [PATCH 08/18] arm64: convert raw syscall invocation to C Date: Mon, 14 May 2018 10:46:30 +0100 Message-Id: <20180514094640.27569-9-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180514094640.27569-1-mark.rutland@arm.com> References: <20180514094640.27569-1-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. 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 | 29 +++++++++++++++++++++++++++++ 3 files changed, 41 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 bf825f38d206..c22e8ace5ea3 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 08ea3cbfb08f..d6e057500eaf 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -873,7 +873,6 @@ 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 @@ -946,15 +945,11 @@ 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) @@ -971,29 +966,18 @@ __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..58d7569f47df --- /dev/null +++ b/arch/arm64/kernel/syscall.c @@ -0,0 +1,29 @@ +// 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, int scno, 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); + } +}