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Message-ID: <2f4234ce-9427-b78c-f7d5-4d9822d4d1c9@suse.com> Date: Tue, 23 May 2023 14:37:06 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 From: Jan Beulich Subject: [PATCH v2] x86: do away with HAVE_AS_NEGATIVE_TRUE To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , Wei Liu , =?utf-8?q?Roger_Pau_Monn=C3=A9?= Content-Language: en-US X-ClientProxiedBy: FR2P281CA0114.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:9d::6) To VE1PR04MB6560.eurprd04.prod.outlook.com (2603:10a6:803:122::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: VE1PR04MB6560:EE_|PA4PR04MB8000:EE_ X-MS-Office365-Filtering-Correlation-Id: ce575273-8c6f-4fb2-2172-08db5b8a6bf3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VE1PR04MB6560.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(39860400002)(396003)(346002)(136003)(376002)(366004)(451199021)(8676002)(8936002)(5660300002)(186003)(26005)(6512007)(6506007)(41300700001)(31686004)(38100700002)(54906003)(66946007)(478600001)(86362001)(31696002)(66556008)(66476007)(316002)(4326008)(6916009)(2616005)(36756003)(2906002)(6486002)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?q?+MQVDYTrM34pp7aqE5WE9PsC7bNP?= =?utf-8?q?fZjGtyKOVZlne8peRzJNVzJYzcoklm+1v+Oq8P2lsVRcmcjwHHuJgXk6yD+C6+aSZ?= =?utf-8?q?W1Yw6ccoiPvAUmQciNJCJQwFw6lx+jLSJXG5XAP5X31G/0yKXy9oCzMpekZHEfJ91?= =?utf-8?q?gL3Md/8m9jwj48l4ACFss/E3AIBAtOx0EtG05ewBNoQlJWX43QO+NrFNNzhppVR0o?= =?utf-8?q?q1GJkT+SEOb+fCicW4mvl7WgTQvVq0cHbXZGzXMGZiF3DOCscJW3vAlpf546iH8fJ?= =?utf-8?q?uV1pcH3qanNB9qvkuqVn2Cxy8HuyzEjRgfKa9PFHRJ7YT9nG0KQuJ+JTRsNkls0rM?= =?utf-8?q?xgcODLw/en/OMqgWVZfy7NbI6u9C+TGG+YcYYrJ3cUoTcyd0+rfL1nQnU3e4o3+u+?= =?utf-8?q?uvVpN6Dp8Y9b/XVxa8sPHyHd9nC2//hkqWocF17uySjck9fHyX0rOm6dxeL6j+my9?= =?utf-8?q?+9e69p+Yvv1I89Z4qVyv+Wr9QU6Hs1I204XU6eEBOpoWjgDKXRXZV/QWBYOUnrLYb?= =?utf-8?q?j2FWKuaH18a+bxm/yYw+NB9uJIR3Mk0xQbHW1/Uik+GDdgpmwgX1YroqLzLVBusUM?= =?utf-8?q?VpZrtIYYculHzTINLQX8RsAvDdQh7RJEBF8MaOIK8X6LFoY+1jcGgNfXnbPPomaGq?= =?utf-8?q?1r2PmuJGGZ+7zQG0v0xHCtTflNQ/cfNBCXk1b4s8a0GSXTORIk5xpJMLgbF8SZIyb?= =?utf-8?q?trHkQQknKYSBXxW7TeaC5sVfWKahNwjHQ5WiQYqq2euMWLtVEa/nHFHgX2t7K0ThT?= =?utf-8?q?S1CUMn+HIE9fm0+XGewAQq71QNR+JLNYTPk63tYzWlNxR4EDyUZAmEbca+aI4oDXM?= =?utf-8?q?buuy70ynNAjY8h7sYgA2Z7BNGSlu/B7pZyNi2bON0HKnyueTqSD4ZNQnyAMrBa6MN?= =?utf-8?q?AWNlh8ehbOGSYfuMPE0U+2Op9BHp5UzHDgOtqwonpTjbvHfMA3GHR5/DBY6j2Tjro?= =?utf-8?q?cwbQnSaZTYhUcpQv5++f3iSIQyWHWvAW+RfAVG2VYoJM/jHjl7xd/li5PvHLkzLTk?= =?utf-8?q?6y0hwBpJAtFa6Ab7JBBDHYleezH43leSSnrEIIVoY2KoOR/FeuH0Q3bZcPjIE861o?= =?utf-8?q?OPcHKYxMSH7niA5krRbJ8ITYuywOgwsXHDp8sV8jNiKmDPR+FnFmN9EFWWL0Z61gl?= =?utf-8?q?qRx+FLWXNnA/W7GknvscaZYLiWyVcriFOKyWtfwCpaqzXA2GUgkPxeSY1g4hU8PFI?= =?utf-8?q?ywwj69uDBrGE/rc99cHicA4OsYLAkFBwxNkIDd8O4TpAKWZ5i8e14wLzn3Cr2z0Ny?= =?utf-8?q?JuEVp40pvB2KzcMD0OoIWLPUmb983YiuRRnEgi1mq0GyJTJcf7uvYDDjxQpKqRTaN?= =?utf-8?q?DwuS4L0y82U5oXiLMneKngQCuN0hFm0x3ZXF5ozK32dMZS2irmgjVYKD0ru/Z1KXZ?= =?utf-8?q?N/3ltQZriTz3xxyBInubmR3h0y8jrHPbsBJ/dVnUmZdteoLFBYzoY3ZmQxZc47H4P?= =?utf-8?q?0g5PqKpqus9eRG0SV0nNUWp7gMPnc1oPYmMikDFMiSitvY+y3CYB+NX5KxZOSfaQI?= =?utf-8?q?3GAgjCvkL1qo?= X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: ce575273-8c6f-4fb2-2172-08db5b8a6bf3 X-MS-Exchange-CrossTenant-AuthSource: VE1PR04MB6560.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 May 2023 12:37:07.9427 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: nI8u7lAEDicmCKvJkXSxuu+rRhroRkLpcl7EDlJ/gBWZXmyl+bKXtpUf1s0PcdFaVj9FHCYiidCvMAOi19XXKg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA4PR04MB8000 There's no real need for the associated probing - we can easily convert to a uniform value without knowing the specific behavior (note also that the respective comments weren't fully correct and have gone stale). No difference in generated code. Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper --- v2: Use "& 1". --- a/xen/arch/x86/arch.mk +++ b/xen/arch/x86/arch.mk @@ -26,10 +26,6 @@ $(call as-option-add,CFLAGS,CC,"invpcid $(call as-option-add,CFLAGS,CC,"movdiri %rax$(comma)(%rax)",-DHAVE_AS_MOVDIR) $(call as-option-add,CFLAGS,CC,"enqcmd (%rax)$(comma)%rax",-DHAVE_AS_ENQCMD) -# GAS's idea of true is -1. Clang's idea is 1 -$(call as-option-add,CFLAGS,CC,\ - ".if ((1 > 0) < 0); .error \"\";.endif",,-DHAVE_AS_NEGATIVE_TRUE) - # Check to see whether the assmbler supports the .nop directive. $(call as-option-add,CFLAGS,CC,\ ".L1: .L2: .nops (.L2 - .L1)$(comma)9",-DHAVE_AS_NOPS_DIRECTIVE) --- a/xen/arch/x86/include/asm/alternative.h +++ b/xen/arch/x86/include/asm/alternative.h @@ -35,19 +35,19 @@ extern void alternative_branches(void); #define alt_repl_e(num) ".LXEN%=_repl_e"#num #define alt_repl_len(num) "(" alt_repl_e(num) " - " alt_repl_s(num) ")" -/* GAS's idea of true is -1, while Clang's idea is 1. */ -#ifdef HAVE_AS_NEGATIVE_TRUE -# define AS_TRUE "-" -#else -# define AS_TRUE "" -#endif +/* + * GAS's idea of true is sometimes 1 and sometimes -1, while Clang's idea + * was consistently 1 up to 6.x (it matches GAS's now). Transform it to + * uniformly 1. + */ +#define AS_TRUE(x) "((" x ") & 1)" -#define as_max(a, b) "(("a") ^ ((("a") ^ ("b")) & -("AS_TRUE"(("a") < ("b")))))" +#define as_max(a, b) "(("a") ^ ((("a") ^ ("b")) & -("AS_TRUE("("a") < ("b")")")))" #define OLDINSTR(oldinstr, padding) \ ".LXEN%=_orig_s:\n\t" oldinstr "\n .LXEN%=_orig_e:\n\t" \ ".LXEN%=_diff = " padding "\n\t" \ - "mknops ("AS_TRUE"(.LXEN%=_diff > 0) * .LXEN%=_diff)\n\t" \ + "mknops ("AS_TRUE(".LXEN%=_diff > 0")" * .LXEN%=_diff)\n\t" \ ".LXEN%=_orig_p:\n\t" #define OLDINSTR_1(oldinstr, n1) \ --- a/xen/arch/x86/include/asm/alternative-asm.h +++ b/xen/arch/x86/include/asm/alternative-asm.h @@ -29,12 +29,12 @@ #endif .endm -/* GAS's idea of true is -1, while Clang's idea is 1. */ -#ifdef HAVE_AS_NEGATIVE_TRUE -# define as_true(x) (-(x)) -#else -# define as_true(x) (x) -#endif +/* + * GAS's idea of true is sometimes 1 and sometimes -1, while Clang's idea + * was consistently 1 up to 6.x (it matches GAS's now). Transform it to + * uniformly 1. + */ +#define as_true(x) ((x) & 1) #define decl_orig(insn, padding) \ .L\@_orig_s: insn; .L\@_orig_e: \