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Thu, 30 Jan 2025 16:53:57 +0100 (CET) From: Andreas Schwab To: Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] riscv/atomic: Do proper sign extension also for unsigned in arch_cmpxchg In-Reply-To: (Alexandre Ghiti's message of "Thu, 30 Jan 2025 16:23:00 +0100") References: Date: Thu, 30 Jan 2025 16:53:57 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Spam-Level: ** X-Spamd-Result: default: False [2.59 / 50.00]; BAYES_HAM(-3.00)[99.99%]; HFILTER_HOSTNAME_UNKNOWN(2.50)[]; RDNS_NONE(2.00)[]; ONCE_RECEIVED(1.20)[]; HFILTER_HELO_IP_A(1.00)[hawking.nue2.suse.org]; NEURAL_HAM_LONG(-1.00)[-1.000]; HFILTER_HELO_NORES_A_OR_MX(0.30)[hawking.nue2.suse.org]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_NO_TLS_LAST(0.10)[]; MX_GOOD(-0.01)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; DIRECT_TO_MX(0.00)[Gnus/5.13 (Gnus v5.13)]; DKIM_TRACE(0.00)[suse.de:+]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; RCVD_COUNT_ONE(0.00)[1]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:dkim,suse.de:mid] X-Spam-Score: 2.59 X-Spamd-Bar: ++ X-Rspamd-Queue-Id: ECB2821119 X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Spam-Flag: NO On Jan 30 2025, Alexandre Ghiti wrote: > a2 is used as it is passed by the calling function, so we can't be sure a2 > is sign extended to me, what am I missing? 32-bit scalar arguments are guaranteed to be sign extended on entry. -- Andreas Schwab, SUSE Labs, schwab@suse.de GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7 "And now for something completely different."