[PATCH v2 20/21] nptl: hppa: Fix Race conditions in pthread cancellation (BZ#12683)

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

This patch adds the hppa modifications required for the BZ#12683.
It basically adds the required __pthread_get_pc function.

HPPA requires an arch-specific syscall_cancel because the
INTERNAL_SYSCALL_NCS adds some instruction to fetch the returned
syscalls value.  The implementation were based on on default C
version built with GCC 6.1

Checked on hppa-linux-gnu.

	[BZ #12683]
	* sysdeps/unix/sysv/linux/hppa/sigcontextinfo.h: New file.
	* sysdeps/unix/sysv/linux/hppa/syscall_cancel.S: Likewise.
---
 ChangeLog                                     |  4 ++
 sysdeps/unix/sysv/linux/hppa/sigcontextinfo.h | 38 +++++++++++++
 sysdeps/unix/sysv/linux/hppa/syscall_cancel.S | 82 +++++++++++++++++++++++++++
 3 files changed, 124 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/hppa/sigcontextinfo.h
 create mode 100644 sysdeps/unix/sysv/linux/hppa/syscall_cancel.S

diff --git a/sysdeps/unix/sysv/linux/hppa/sigcontextinfo.h b/sysdeps/unix/sysv/linux/hppa/sigcontextinfo.h
new file mode 100644
index 0000000..4f59c1e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/hppa/sigcontextinfo.h
@@ -0,0 +1,38 @@
+/* Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SIGCONTEXTINFO_H
+#define _SIGCONTEXTINFO_H
+
+#include <stdint.h>
+
+/* In general we cannot provide any information.  */
+#define SIGCONTEXT struct sigcontext *
+#define SIGCONTEXT_EXTRA_ARGS
+#define GET_PC(ctx)	((void *) 0)
+#define GET_FRAME(ctx)	((void *) 0)
+#define GET_STACK(ctx)	((void *) 0)
+#define CALL_SIGHANDLER(handler, signo, ctx) \
+  (handler)((signo), SIGCONTEXT_EXTRA_ARGS (ctx))
+
+static inline uintptr_t
+ucontext_get_pc (const ucontext_t *uc)
+{
+  return uc->uc_mcontext.sc_iaoq[0] & ~0x3;
+}
+
+#endif /* _SIGCONTEXTINFO_H  */
diff --git a/sysdeps/unix/sysv/linux/hppa/syscall_cancel.S b/sysdeps/unix/sysv/linux/hppa/syscall_cancel.S
new file mode 100644
index 0000000..552ba2f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/hppa/syscall_cancel.S
@@ -0,0 +1,82 @@
+/* Cancellable syscall wrapper.  Linux/hppa version.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+/* long int __syscall_cancel_arch (int *cancelhandling,
+				   long int nr,
+				   long int arg1,
+				   long int arg2,
+				   long int arg3,
+				   long int arg4,
+				   long int arg5,
+				   long int arg6)  */
+
+	.text
+ENTRY(__syscall_cancel_arch)
+	stw	%r2,-20(%r30)
+	ldo	128(%r30),%r30
+	cfi_def_cfa_offset (-128)
+	cfi_offset (2, -20)
+	ldw	-180(%r30),%r28
+	copy	%r24,%r31
+	stw	%r28,-104(%r30)
+	ldw	-184(%r30),%r28
+	stw	%r28,-108(%r30)
+	ldw	-188(%r30),%r28
+	stw	%r28,-112(%r30)
+	ldw	-192(%r30),%r28
+	stw	%r4,-100(%r30)
+	stw	%r28,-116(%r30)
+	copy	%r25,%r28
+	copy	%r23,%r25
+	stw	%r19,-32(%r30)
+	cfi_offset (4, 28)
+
+	.global __syscall_cancel_arch_start
+.type __syscall_cancel_arch_start,@function
+__syscall_cancel_arch_start:
+
+	ldw	0(%r26),%r20
+	stw	%r20,-120(%r30)
+	ldw	-120(%r30),%r20
+	bb,<	%r20,29,1f
+	ldw	-116(%r30),%r21
+	ldw	-112(%r30),%r22
+	copy	%r31,%r26
+	ldw	-108(%r30),%r23
+	ldw	-104(%r30),%r24
+	copy	%r19, %r4
+	ble	0x100(%sr2, %r0)
+
+	.global __syscall_cancel_arch_end
+.type __syscall_cancel_arch_end,@function	
+__syscall_cancel_arch_end:
+
+	copy	%r28, %r20
+	copy	%r4, %r19
+	ldw	-148(%r30),%r2
+	ldw	-100(%r30),%r4
+	bv	%r0(%r2)
+	ldo	-128(%r30),%r30
+1:
+	bl __syscall_do_cancel,%r2
+	nop
+	nop
+END(__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)
-- 
2.7.4