Message ID | 20241029-arm-generic-entry-v2-21-573519abef38@linaro.org (mailing list archive) |
---|---|
State | New |
Headers | show
Return-Path: <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org> X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ED9FAD2AB20 for <linux-arm-kernel@archiver.kernel.org>; Tue, 29 Oct 2024 11:42:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=P2OP9NgXP8OYjhdkePmH5sP15xkO/BVCD1VA0/cLgTg=; b=vzt0Jmctn+9o87mMJSR7yeQHeh Mmfjs3U4Y8c0pSTV8Ht4+eNJ+bnJRDvHNkjM3gvo3CPKkCGCJ/bFdOOkIdaLK7jNe6uA8MAkn7sgi raVCmhWlvBuKDcwdnsqTpKV8uZjS2m+NfDZIA6bpfc0rhlSHhaZ9ol3sMyi32QosZZSuOYQZ/09ra o4/TpKZy+igw9iHWlcLr8AswHBxN5WHF31gzreywot15OuQqNIbxEi7Bsn1DHk2lPF1kk1BepSVOi KD3IUPNyJ5PJ6RhOO02CSWgGEq7B2qYF3yB2io3uXwzSwdBOL27Y7KUJTreiYR2Xw/s10ak4wyMOC Iw0hawnQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t5kbo-0000000EGQi-2SLm; Tue, 29 Oct 2024 11:42:00 +0000 Received: from mail-lf1-x129.google.com ([2a00:1450:4864:20::129]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t5jqo-0000000E7ST-0USk for linux-arm-kernel@lists.infradead.org; Tue, 29 Oct 2024 10:53:27 +0000 Received: by mail-lf1-x129.google.com with SMTP id 2adb3069b0e04-539f72c8fc1so6476625e87.1 for <linux-arm-kernel@lists.infradead.org>; Tue, 29 Oct 2024 03:53:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1730199205; x=1730804005; darn=lists.infradead.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=P2OP9NgXP8OYjhdkePmH5sP15xkO/BVCD1VA0/cLgTg=; b=P/LqQ+HCejdyGCc4GFCd4AQHRNECb5e1drua/aC1fGD4GvDOjT85FkJsieaE35PoIF R6fnr6ItNRP+7UXX7Co1JPb+Et9K0fNg6NSQh3IRtbW/Ok30cnaoenT15Al5bt4rgolA sPeJLNpGaKh0wXKMYtoFaW2f4z8kQ0b94VOg5a6xf4SEzatSrXJR4IZsUVJzwfpNayjG Ny+r+/KbrdFlGjFdIfmpybCSrPuWmjkC/ttD1eeV02psuNGBvWaF6YTnRcf2ix82A9kE VBF9uOxUyQIchtHVf3gvVnBA0Ldb8V3bglTWrtutNh0LPXGmvkYPcpE3ugdRBzCbiyPm YEwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730199205; x=1730804005; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=P2OP9NgXP8OYjhdkePmH5sP15xkO/BVCD1VA0/cLgTg=; b=ZIOsY9wbBbB6EAr4gEu5kWmoL7eWdeHnSEXcK6et26pFTSPanVfh+RWmmhwJAZPC2T 0I1dBKbJSmapslFebqCcZUyhZPVbUesq+2V3DsAnCZ4d/JzcTWj1IjHZn2wbVKDUKEUs +s55BFw/9G4SgaWfA3ip0/tM/MgdBEDM/H0GMufggIszokcBGoxF40ojaiqe47Pfp5i6 WvTI87nxO8fR3aggczEAJcfWPTvdQPHDO5md8skU7SYfFwUiA0sxNld8VrHWguUvEziQ nAsxJNpa+H3LHKdgTdPfwTbiB8l+1ZUf/6YDHwo6PikXyTdX2+M464/xVgbXZH3WD97y ABNA== X-Gm-Message-State: AOJu0YxpELe2Qb8IEPjdIADCx16Whn+vJYIvwQMlaLCCSMg4oLehOH0Y Qf0leAlk5Q6BVdoADNY+dtDZxoDPZcwum17x209s1AciV8IJPlgNo/X3niJvdJ9igI+pcI8CarE N X-Google-Smtp-Source: AGHT+IFllmxwh7EKDe/a3WvQfs+EHBA3khsZLhUnL3Z+I/JP6m6A/TkF2H92CKvNJpKEWjTk3WNgUA== X-Received: by 2002:a05:6512:4022:b0:539:fbfd:fc74 with SMTP id 2adb3069b0e04-53b3491cccdmr5480123e87.40.1730199204557; Tue, 29 Oct 2024 03:53:24 -0700 (PDT) Received: from lino.lan ([85.235.12.238]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-53b2e12452fsm1351307e87.73.2024.10.29.03.53.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Oct 2024 03:53:23 -0700 (PDT) From: Linus Walleij <linus.walleij@linaro.org> Date: Tue, 29 Oct 2024 11:53:01 +0100 Subject: [PATCH RFC v2 21/28] ARM: entry: Do not double-call exit functions MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20241029-arm-generic-entry-v2-21-573519abef38@linaro.org> References: <20241029-arm-generic-entry-v2-0-573519abef38@linaro.org> In-Reply-To: <20241029-arm-generic-entry-v2-0-573519abef38@linaro.org> To: Oleg Nesterov <oleg@redhat.com>, Russell King <linux@armlinux.org.uk>, Kees Cook <kees@kernel.org>, Andy Lutomirski <luto@amacapital.net>, Will Drewry <wad@chromium.org>, Frederic Weisbecker <frederic@kernel.org>, "Paul E. McKenney" <paulmck@kernel.org>, Jinjie Ruan <ruanjinjie@huawei.com>, Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ardb@kernel.org>, Al Viro <viro@zeniv.linux.org.uk> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Linus Walleij <linus.walleij@linaro.org> X-Mailer: b4 0.14.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241029_035326_248571_4EB14396 X-CRM114-Status: GOOD ( 17.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: <linux-arm-kernel.lists.infradead.org> List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-arm-kernel>, <mailto:linux-arm-kernel-request@lists.infradead.org?subject=unsubscribe> List-Archive: <http://lists.infradead.org/pipermail/linux-arm-kernel/> List-Post: <mailto:linux-arm-kernel@lists.infradead.org> List-Help: <mailto:linux-arm-kernel-request@lists.infradead.org?subject=help> List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-arm-kernel>, <mailto:linux-arm-kernel-request@lists.infradead.org?subject=subscribe> Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org |
Series |
ARM: Switch to generic entry
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expand
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diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index ece921571714..33bc9e7c5b32 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -49,7 +49,7 @@ ret_fast_syscall: tst r1, #_TIF_SYSCALL_WORK beq 1f - b ret_to_user + b 2f 1: mov r0, sp @ 'regs' bl do_work_pending
This is a semantic change to ret_fast_syscall: if there is no work pending the function used to jump to ret_to_user, instead we proceed to return from the syscall. If we jump to ret_to_user, IRQs are enabled and we call syscall_exit_to_user_mode a second time; at this point a this just means a second call to rseq_syscall(), but it seems wrong and we want syscall_exit_to_user_mode to be called exactly once. Apparently the ARM kernel has under some circumstances called rseq_syscall() twice on the exit to userspace without side effects. ret_to_user also checks for pending work a second time under ret_to_user_from_irq, but this isn't even needed any more on the fast return path: this was needed because the syscall invocation enabled interrupts when doing syscall tracing, and all tracing invocation has been moved over to C in earlier patches. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- arch/arm/kernel/entry-common.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)