From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21539 invoked by alias); 11 Jan 2004 20:31:02 -0000 Mailing-List: contact libc-hacker-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-hacker-owner@sources.redhat.com Received: (qmail 21523 invoked from network); 11 Jan 2004 20:31:02 -0000 Received: from unknown (HELO Cantor.suse.de) (195.135.220.2) by sources.redhat.com with SMTP; 11 Jan 2004 20:31:02 -0000 Received: from Hermes.suse.de (Hermes.suse.de [195.135.221.8]) (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) (No client certificate requested) by Cantor.suse.de (Postfix) with ESMTP id D4AC419A5173; Sun, 11 Jan 2004 21:29:04 +0100 (CET) Received: from aj by arthur.inka.de with local (Exim 4.22) id 1AfmCk-0007Us-S4; Sun, 11 Jan 2004 21:29:02 +0100 To: Richard Henderson Cc: Jakub Jelinek , Glibc hackers Subject: Re: [PATCH] Fix AMD64 backtrace References: <20040110175049.GM6413@sunsite.ms.mff.cuni.cz> <20040111024737.A1431@redhat.com> <20040111025223.A2564@redhat.com> <20040111030005.C13258@redhat.com> <20040111202020.GB24540@redhat.com> From: Andreas Jaeger Date: Sun, 11 Jan 2004 20:31:00 -0000 In-Reply-To: <20040111202020.GB24540@redhat.com> (Richard Henderson's message of "Sun, 11 Jan 2004 12:20:20 -0800") Message-ID: User-Agent: Gnus/5.1006 (Gnus v5.10.6) XEmacs/21.4 (Rational FORTRAN, linux) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" X-SW-Source: 2004-01/txt/msg00047.txt.bz2 --=-=-= Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-length: 2418 Richard Henderson writes: > On Sun, Jan 11, 2004 at 01:17:52PM +0100, Andreas Jaeger wrote: >> pushq %rcx >> cfi_adjust_cfa_offset(8) > > Jakub already pointed out that this is wrong. > >> /* We changed %rdi, fix cfi. */ >> cfi_def_cfa(%rsp, 0) > > But the push means this is wrong too -- the CFA is rsp+8. > > Also wrong at this point is the return address. The value > is now stored at CFA-8, where we pushed it above. This would give the following routine: ENTRY(__setcontext) /* Save argument since syscall will destroy it. */ pushq %rdi cfi_adjust_cfa_offset(8) /* Set the signal mask with rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */ leaq oSIGMASK(%rdi), %rsi xorq %rdx, %rdx movq $SIG_SETMASK, %rdi movq $_NSIG8,%r10 movq $__NR_rt_sigprocmask, %rax syscall popq %rdi /* Reload %rdi, adjust stack. */ cfi_adjust_cfa_offset(-8) cmpq $-4095, %rax /* Check %rax for error. */ jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ /* Restore the floating-point context. Not the registers, only the rest. */ movq oFPREGS(%rdi), %rcx fldenv (%rcx) ldmxcsr oMXCSR(%rdi) /* Load the new stack pointer, the preserved registers and registers used for passing args. */ cfi_def_cfa(%rdi, 0) cfi_offset(%rbx,oRBX) cfi_offset(%rbp,oRBP) cfi_offset(%r12,oR12) cfi_offset(%r13,oR13) cfi_offset(%r14,oR14) cfi_offset(%r15,oR15) cfi_offset(%rsp,oRSP) cfi_offset(%rip,oRIP) =09 movq oRSP(%rdi), %rsp movq oRBX(%rdi), %rbx movq oRBP(%rdi), %rbp movq oR12(%rdi), %r12 movq oR13(%rdi), %r13 movq oR14(%rdi), %r14 movq oR15(%rdi), %r15 /* The following ret should return to the address set with getcontext. Therefore push the address on the stack. */ movq oRIP(%rdi), %rcx pushq %rcx movq oRSI(%rdi), %rsi movq oRDX(%rdi), %rdx movq oRCX(%rdi), %rcx movq oR8(%rdi), %r8 movq oR9(%rdi), %r9 /* Setup finally %rdi. */ movq oRDI(%rdi), %rdi /* We changed %rdi, fix cfi. */ cfi_def_cfa(%rsp, 8) cfi_same_value(%rbx) cfi_same_value(%rbp) cfi_same_value(%r12) cfi_same_value(%r13) cfi_same_value(%r14) cfi_same_value(%r15) cfi_offset(%rip,-8) /* Clear rax to indicate success. */ xorq %rax, %rax Thanks, Andreas --=20 Andreas Jaeger, aj@suse.de, http://www.suse.de/~aj SuSE Linux AG, Maxfeldstr. 5, 90409 N=FCrnberg, Germany GPG fingerprint =3D 93A3 365E CE47 B889 DF7F FED1 389A 563C C272 A126 --=-=-= Content-Type: application/pgp-signature Content-length: 188 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQBAAbIOOJpWPMJyoSYRAnA0AKCUvzZGWl/79yQRg5dNCMSVwQFE1gCeL6/5 J7KUgWTSKjiuVR/bZfe/TvI= =ziW1 -----END PGP SIGNATURE----- --=-=-=--