From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/10731 Path: news.gmane.org!.POSTED!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: [PATCH v2] fix x86_64 sigreturn trampoline so gdb recognizes it Date: Sun, 13 Nov 2016 01:12:05 +0100 Message-ID: <20161113001205.GR5749@port70.net> References: <20161112170712.GP5749@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1478995962 27673 195.159.176.226 (13 Nov 2016 00:12:42 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 13 Nov 2016 00:12:42 +0000 (UTC) User-Agent: Mutt/1.6.0 (2016-04-01) To: musl@lists.openwall.com Original-X-From: musl-return-10744-gllmg-musl=m.gmane.org@lists.openwall.com Sun Nov 13 01:12:39 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1c5iPA-00040N-LF for gllmg-musl@m.gmane.org; Sun, 13 Nov 2016 01:12:16 +0100 Original-Received: (qmail 3472 invoked by uid 550); 13 Nov 2016 00:12:18 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 3443 invoked from network); 13 Nov 2016 00:12:17 -0000 Mail-Followup-To: musl@lists.openwall.com Content-Disposition: inline In-Reply-To: <20161112170712.GP5749@port70.net> Xref: news.gmane.org gmane.linux.lib.musl.general:10731 Archived-At: gdb can only unwind across signal handlers if it recognizes the trampoline. on x86_64 this means the pc must be in a function called __restore_rt or if gdb cannot determine the symbol name the instruction sequence must match to what gdb expects. a nop is added before __restore_rt, the __restore alias is removed and size annotation is added to make sure gdb maps any pc value within __restore_rt unambigously to the __restore_rt symbol name. and the instruction sequence got fixed to match what gdb expects. --- arch/x86_64/ksigaction.h | 9 +++++++++ src/signal/x86_64/restore.s | 7 +++---- 2 files changed, 12 insertions(+), 4 deletions(-) create mode 100644 arch/x86_64/ksigaction.h diff --git a/arch/x86_64/ksigaction.h b/arch/x86_64/ksigaction.h new file mode 100644 index 0000000..7743c5c --- /dev/null +++ b/arch/x86_64/ksigaction.h @@ -0,0 +1,9 @@ +struct k_sigaction { + void (*handler)(int); + unsigned long flags; + void (*restorer)(void); + unsigned mask[2]; +}; + +void __restore_rt(); +#define __restore __restore_rt diff --git a/src/signal/x86_64/restore.s b/src/signal/x86_64/restore.s index 682af2d..b5c6e37 100644 --- a/src/signal/x86_64/restore.s +++ b/src/signal/x86_64/restore.s @@ -1,8 +1,7 @@ + nop .global __restore_rt -.global __restore .type __restore_rt,@function -.type __restore,@function __restore_rt: -__restore: - movl $15, %eax + mov $15, %rax syscall +.size __restore_rt,.-__restore_rt -- 2.10.2