From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 31174 invoked from network); 9 Jun 2020 01:02:11 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 9 Jun 2020 01:02:11 -0000 Received: (qmail 3886 invoked by uid 550); 9 Jun 2020 01:02:03 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 3857 invoked from network); 9 Jun 2020 01:02:03 -0000 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1591664523; h=Content-Transfer-Encoding: Content-Type: MIME-Version: Message-ID: Date: Subject: In-Reply-To: References: To: From: Sender; bh=eEu6Tfyme/QbNZOiTDsogKX7UpCjRnMUYQL2w32dFEY=; b=qLF0eo3pL61SRZEqJl7JkpOam+t4ituZKL1N/BYQ9gpraIdhEacOxJj+9d+RnfaC8IfATQCO QHHFALiJMxJdJypFJ1r3ZW+bFkhsEuawPZ1+Sj7xqoDdqCJXomPlQAleQEp1yF8qZ4E9rIAm W4m4IEUOgwBTeOoHChgWqJfvnTU= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyI1MGQzMyIsICJtdXNsQGxpc3RzLm9wZW53YWxsLmNvbSIsICJiZTllNGEiXQ== Sender: sidneym=codeaurora.org@mg.codeaurora.org DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 63B4DC43391 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=sidneym@codeaurora.org From: To: References: <036c01d63d36$73c42110$5b4c6330$@codeaurora.org> <20200608171057.GC1079@brightrain.aerifal.cx> In-Reply-To: <20200608171057.GC1079@brightrain.aerifal.cx> Date: Mon, 8 Jun 2020 20:01:24 -0500 Message-ID: <0bbd01d63df9$7fd69a50$7f83cef0$@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQHfikOQM2lGCwPrn1tVskxFRUd5xwI3AqQLqKsXq+A= Content-Language: en-us Subject: RE: [musl] sigsetjmp > -----Original Message----- > From: Rich Felker > Sent: Monday, June 8, 2020 12:11 PM > To: sidneym@codeaurora.org > Cc: musl@lists.openwall.com > Subject: Re: [musl] sigsetjmp > > On Sun, Jun 07, 2020 at 08:45:11PM -0500, sidneym@codeaurora.org wrote: > > Wanting to make sure I'm reading the requirements correctly. > > > > Looks like this routine only needs to save the link register and env, > > call setjmp then restore the link register and env followed by the tail call. > > Yes, that's correct. This is an unconventional design but necessary so that the > stack frame has already been restored when signals are unmasked by > siglongjmp. See the message for commit > 583e55122e767b1586286a0d9c35e2a4027998ab for a description of how this > works. > > > Hexagon was out of date so I did this: > > > > > > > > ..balign 4 > > > > ..type sigsetjmp,@function > > > > sigsetjmp: > > > > // if savemask is 0 sigsetjmp behaves like setjmp > > > > { > > > > p0 = cmp.eq(r1, #0) > > > > if (p0.new) jump:t ##setjmp > > > > } > > > > { > > > > memw(r0+#64+4) = r16 // save r16 in __ss[0] > > > > memw(r0+#64) = r31 // save linkregister in __fl > > > > r16 = r0 > > > > } > > This is not correct. __ss[0] is occupied by the saved signal mask, and will be > clobbered when it's saved in the tail call. Instead you need to use unused space > in struct __jmp_buf_tag. The canonical place is > (char*)__ss+8 (the "HURD ABI area" :) assuming _NSIG==65. I was not able to find a description of the HURD ABI area is it documented someplace? So upon entry to sigsetjmp __ss[0] is holding the saved mask and using __ss[0] to buffer r16 will clobber it, correct? As it is coded __ss[0] is just used over the call to setjmp to preserve the value of r16. If __ss is r0+#64+4, then you are suggesting that I use r0+#64+4+8 or __ss[2]. I need to look into this some more because with that I'm have some testcase issues. Thanks, > > Rich