From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0CD5C433F5 for ; Tue, 9 Nov 2021 22:44:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7A2060524 for ; Tue, 9 Nov 2021 22:44:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242255AbhKIWrU (ORCPT ); Tue, 9 Nov 2021 17:47:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:36108 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346262AbhKIWoK (ORCPT ); Tue, 9 Nov 2021 17:44:10 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A4DFA61B47; Tue, 9 Nov 2021 22:24:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636496686; bh=iudG8ri3aafLAIe2fV+orn+ebUq8ci3wOfMOvnn/MR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BjbUw2Z4oMlSbr04KKxTVGILQm8XKyMBQ2TgEEm6Dk5dyuiLeo8AB+ylKKQNC80Zm DSxgMoWHaf5fbFUkSVsbw+l3f0Yy/2ZazBTAFL3Pj1N+q3CU0rOYoLJGlT9rjM/xii B5a8P1p5lH5YW7AE7Rcuu4vGpiCptYR898f9zcaCNFe6ajiqkpHEGdMhys8hgdO4Rs l16Ahy/hHqy6MdsXa5vm0UR3JSFIOG/U9I7BVYVkjYhgGmltVQC1Duh/gluROz2FFi 2dej57opVc+AotgNUXwlYXTUst3Q/NW1qZ/a8QA+IAolWxotBcwCyDa0W3LlCErDBA 95GAwej4q8ixw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Michael Ellerman , Nick Desaulniers , Sasha Levin , benh@kernel.crashing.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.4 12/12] powerpc/dcr: Use cmplwi instead of 3-argument cmpli Date: Tue, 9 Nov 2021 17:24:26 -0500 Message-Id: <20211109222426.1236575-12-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211109222426.1236575-1-sashal@kernel.org> References: <20211109222426.1236575-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Ellerman [ Upstream commit fef071be57dc43679a32d5b0e6ee176d6f12e9f2 ] In dcr-low.S we use cmpli with three arguments, instead of four arguments as defined in the ISA: cmpli cr0,r3,1024 This appears to be a PPC440-ism, looking at the "PPC440x5 CPU Core User’s Manual" it shows cmpli having no L field, but implied to be 0 due to the core being 32-bit. It mentions that the ISA defines four arguments and recommends using cmplwi. It also corresponds to the old POWER instruction set, which had no L field there, a reserved bit instead. dcr-low.S is only built 32-bit, because it is only built when DCR_NATIVE=y, which is only selected by 40x and 44x. Looking at the generated code (with gcc/gas) we see cmplwi as expected. Although gas is happy with the 3-argument version when building for 32-bit, the LLVM assembler is not and errors out with: arch/powerpc/sysdev/dcr-low.S:27:10: error: invalid operand for instruction cmpli 0,%r3,1024; ... ^ Switch to the cmplwi extended opcode, which avoids any confusion when reading the ISA, fixes the issue with the LLVM assembler, and also means the code could be built 64-bit in future (though that's very unlikely). Reported-by: Nick Desaulniers Reviewed-by: Nick Desaulniers Signed-off-by: Michael Ellerman BugLink: https://github.com/ClangBuiltLinux/linux/issues/1419 Link: https://lore.kernel.org/r/20211014024424.528848-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin --- arch/powerpc/sysdev/dcr-low.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/sysdev/dcr-low.S b/arch/powerpc/sysdev/dcr-low.S index d3098ef1404a2..3943d19d5f63b 100644 --- a/arch/powerpc/sysdev/dcr-low.S +++ b/arch/powerpc/sysdev/dcr-low.S @@ -14,7 +14,7 @@ #include #define DCR_ACCESS_PROLOG(table) \ - cmpli cr0,r3,1024; \ + cmplwi cr0,r3,1024; \ rlwinm r3,r3,4,18,27; \ lis r5,table@h; \ ori r5,r5,table@l; \ -- 2.33.0