From patchwork Mon Jul 2 11:04:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 10500973 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 007B060362 for ; Mon, 2 Jul 2018 11:05:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E28F5286F7 for ; Mon, 2 Jul 2018 11:05:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D5D41286F1; Mon, 2 Jul 2018 11:05:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 583DC286F1 for ; Mon, 2 Jul 2018 11:05:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030397AbeGBLFA (ORCPT ); Mon, 2 Jul 2018 07:05:00 -0400 Received: from foss.arm.com ([217.140.101.70]:57540 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030359AbeGBLEr (ORCPT ); Mon, 2 Jul 2018 07:04:47 -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 09AFB18A; Mon, 2 Jul 2018 04:04:47 -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 ED63F3F5BA; Mon, 2 Jul 2018 04:04:44 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, will.deacon@arm.com Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com, dave.martin@arm.com, hch@infradead.org, 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 Subject: [PATCHv4 09/19] arm64: convert native/compat syscall entry to C Date: Mon, 2 Jul 2018 12:04:05 +0100 Message-Id: <20180702110415.10465-10-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180702110415.10465-1-mark.rutland@arm.com> References: <20180702110415.10465-1-mark.rutland@arm.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Now that the syscall invocation logic is in C, we can migrate the rest of the syscall entry logic over, so that the entry assembly needn't look at the register values at all. The SVE reset across syscall logic now unconditionally clears TIF_SVE, but sve_user_disable() will only write back to CPACR_EL1 when SVE is actually enabled. Signed-off-by: Mark Rutland Reviewed-by: Catalin Marinas Reviewed-by: Dave Martin Cc: Will Deacon --- arch/arm64/kernel/entry.S | 42 ++++-------------------------------------- arch/arm64/kernel/syscall.c | 41 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 43 insertions(+), 40 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 05b9f03f3e00..156c4e3fd1a4 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -720,14 +720,9 @@ el0_sync_compat: b.ge el0_dbg b el0_inv el0_svc_compat: - /* - * AArch32 syscall handling - */ - ldr x16, [tsk, #TSK_TI_FLAGS] // load thread flags - adrp stbl, compat_sys_call_table // load compat syscall table pointer - mov wscno, w7 // syscall number in w7 (r7) - mov wsc_nr, #__NR_compat_syscalls - b el0_svc_naked + mov x0, sp + bl el0_svc_compat_handler + b ret_to_user .align 6 el0_irq_compat: @@ -925,37 +920,8 @@ ENDPROC(ret_to_user) */ .align 6 el0_svc: - ldr x16, [tsk, #TSK_TI_FLAGS] // load thread flags - adrp stbl, sys_call_table // load syscall table pointer - mov wscno, w8 // syscall number in w8 - mov wsc_nr, #__NR_syscalls - -#ifdef CONFIG_ARM64_SVE -alternative_if_not ARM64_SVE - b el0_svc_naked -alternative_else_nop_endif - tbz x16, #TIF_SVE, el0_svc_naked // Skip unless TIF_SVE set: - bic x16, x16, #_TIF_SVE // discard SVE state - str x16, [tsk, #TSK_TI_FLAGS] - - /* - * task_fpsimd_load() won't be called to update CPACR_EL1 in - * ret_to_user unless TIF_FOREIGN_FPSTATE is still set, which only - * happens if a context switch or kernel_neon_begin() or context - * modification (sigreturn, ptrace) intervenes. - * So, ensure that CPACR_EL1 is already correct for the fast-path case: - */ - mrs x9, cpacr_el1 - bic x9, x9, #CPACR_EL1_ZEN_EL0EN // disable SVE for el0 - msr cpacr_el1, x9 // synchronised by eret to el0 -#endif - -el0_svc_naked: // compat entry point mov x0, sp - mov w1, wscno - mov w2, wsc_nr - mov x3, stbl - bl el0_svc_common + bl el0_svc_handler b ret_to_user ENDPROC(el0_svc) diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index e3153ffe7f8e..ea4fc5eea182 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -8,7 +8,9 @@ #include #include +#include #include +#include long compat_arm_syscall(struct pt_regs *regs); @@ -61,8 +63,8 @@ static inline bool has_syscall_work(unsigned long flags) int syscall_trace_enter(struct pt_regs *regs); void syscall_trace_exit(struct pt_regs *regs); -asmlinkage void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, - syscall_fn_t syscall_table[]) +static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, + syscall_fn_t syscall_table[]) { unsigned long flags = current_thread_info()->flags; @@ -99,3 +101,38 @@ asmlinkage void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, trace_exit: syscall_trace_exit(regs); } + +static inline void sve_user_discard(void) +{ + if (!system_supports_sve()) + return; + + clear_thread_flag(TIF_SVE); + + /* + * task_fpsimd_load() won't be called to update CPACR_EL1 in + * ret_to_user unless TIF_FOREIGN_FPSTATE is still set, which only + * happens if a context switch or kernel_neon_begin() or context + * modification (sigreturn, ptrace) intervenes. + * So, ensure that CPACR_EL1 is already correct for the fast-path case. + */ + sve_user_disable(); +} + +extern syscall_fn_t sys_call_table[]; + +asmlinkage void el0_svc_handler(struct pt_regs *regs) +{ + sve_user_discard(); + el0_svc_common(regs, regs->regs[8], __NR_syscalls, sys_call_table); +} + +#ifdef CONFIG_COMPAT +extern syscall_fn_t compat_sys_call_table[]; + +asmlinkage void el0_svc_compat_handler(struct pt_regs *regs) +{ + el0_svc_common(regs, regs->regs[7], __NR_compat_syscalls, + compat_sys_call_table); +} +#endif