From patchwork Tue May 9 09:16:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 1778836 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20221208 header.b=E61D3B2b; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QFsxZ0Yh8z20fl for ; Tue, 9 May 2023 19:17:22 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4QFsxY6Lyyz3fLP for ; Tue, 9 May 2023 19:17:21 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20221208 header.b=E61D3B2b; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::42d; helo=mail-pf1-x42d.google.com; envelope-from=npiggin@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20221208 header.b=E61D3B2b; dkim-atps=neutral Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4QFswF63XBz3cKV for ; Tue, 9 May 2023 19:16:13 +1000 (AEST) Received: by mail-pf1-x42d.google.com with SMTP id d2e1a72fcca58-643465067d1so4223638b3a.0 for ; Tue, 09 May 2023 02:16:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683623771; x=1686215771; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=QQRVEMdxg3bJ3RT58FLQe3azlS0hXknq+d2s1ifzqZw=; b=E61D3B2b5EzVlMpJ3qNe+XkV0VIWGv6szlrRvG3gNeeQkoqvocSjKXmkw3n7UP3jq4 elArqE4qnHyPug0OjAht/quWvc41KF/y5n3OAfAfm7dKS//JcI4PJ0Dd/dEzbhs26rf+ gF8J+DvqR7QSFHiC8i1SiVR0lUEEs1hfSv0yThCgLGI2bw+k+ZbOk/x7UleuPfR93gxL +VzB2RY54DVeE4z8LkevKUigBKgFskHlskhC4l1wQfCLrWA27RxLps+3D72/lO8waEf/ YWRHsrKmSMOUi1jhCbzWTjV20ouCgO6Jl2bBfw1DmDRyraQfRcm5kUSQ8OflZYRWhBEs 5zgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683623771; x=1686215771; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=QQRVEMdxg3bJ3RT58FLQe3azlS0hXknq+d2s1ifzqZw=; b=BrPDHm8QxdQxethynn5D1+0a8R98xTudQt3T+rkihPi2fjOX09fi1vwYDUkLQvYegf JL3njSULqSPO6G8efsuQkhtk1Bj+NkXVIHR22r3Qyh4K9hpFpSh0Mdk58tOyXJZ471rJ fuRYUDymf4HIKmLJb1IfcG29kShIO3mJ/XYfp6ROFYp24Hy7NMuUzK1bQn4yGuVCAaW5 Uj9dAi9hTy9euVEWuOUr08F4nVSO0LpQFVTbWUta/7jCo8Jr7xBFJiOaPKkKNMX1Stkh K7R28Ku/Ul3QmtCe7rvl/5fWPkWbhHIN7EylZWdQ60XFbglt64M3e7CGEeMhfVPhpvs9 trXg== X-Gm-Message-State: AC+VfDzGHVXzjqcM7pCAvEU8ejqLFCfK3pnJOMPPF9xH5MUACt8vZZ7W GJEC2QQE3u/QafDL4QzqDtvifhtfVs0= X-Google-Smtp-Source: ACHHUZ6gz9Srf7ZoD58Q1isbS5QQ/3u4aSYkbOYFr3KFJrOIzllaD0uEF35umHXiJuywh/Rbbt65rw== X-Received: by 2002:a05:6a00:2e0e:b0:63d:24c0:1223 with SMTP id fc14-20020a056a002e0e00b0063d24c01223mr18809572pfb.29.1683623771619; Tue, 09 May 2023 02:16:11 -0700 (PDT) Received: from wheely.local0.net ([118.208.131.108]) by smtp.gmail.com with ESMTPSA id z11-20020a65610b000000b00528db73ed70sm874353pgu.3.2023.05.09.02.16.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 02:16:11 -0700 (PDT) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH 2/2] powerpc/pseries: Remove unused hcall tracing instruction Date: Tue, 9 May 2023 19:16:00 +1000 Message-Id: <20230509091600.70994-2-npiggin@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230509091600.70994-1-npiggin@gmail.com> References: <20230509091600.70994-1-npiggin@gmail.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nicholas Piggin Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When JUMP_LABEL=n, the tracepoint refcount test in the pre-call stores the refcount value to the stack, so the same value can be used for the post-call (presumably to avoid racing with the value concurrently changing). On little-endian (ELFv2) that might have just worked by luck, because 32(r1) is STK_PARAM(R3) there and so the value save gets clobbered by the tracing code when it's non-zero, but fortunately r3 is the hcall number and 0 is an invalid hcall number so it should get clobbered by another non-zero value. In any case, commit cc1adb5f32557 ("powerpc/pseries: Use jump labels for hcall tracepoints") removed the code that actually used the value stored, so now it's just dead code. It's fragile to be storing to the stack like this, and confusing. Better remove it. Signed-off-by: Nicholas Piggin --- arch/powerpc/platforms/pseries/hvCall.S | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S index ca0674b0b683..bae45b358a09 100644 --- a/arch/powerpc/platforms/pseries/hvCall.S +++ b/arch/powerpc/platforms/pseries/hvCall.S @@ -92,7 +92,6 @@ BEGIN_FTR_SECTION; \ END_FTR_SECTION(0, 1); \ LOAD_REG_ADDR(r12, hcall_tracepoint_refcount) ; \ ld r12,0(r12); \ - std r12,32(r1); \ cmpdi r12,0; \ bne- LABEL; \ 1: