1 files changed, 65 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/cancellation-pc-check.h b/sysdeps/unix/sysv/linux/powerpc/cancellation-pc-check.h
new file mode 100644
index 0000000000..1175e1a070
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/cancellation-pc-check.h
@@ -0,0 +1,65 @@
+/* Architecture specific code for pthread cancellation handling.
+   Linux/PowerPC version.
+   Copyright (C) 2023 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 _NPTL_CANCELLATION_PC_CHECK
+#define _NPTL_CANCELLATION_PC_CHECK
+
+#include <sigcontextinfo.h>
+
+/* For syscalls with side-effects (e.g read that might return partial read),
+   the kernel cannot restart the syscall when interrupted by a signal, it must
+   return from the call with whatever partial result.  In this case, the saved
+   program counter is set just after the syscall instruction, so the SIGCANCEL
+   handler should not act on cancellation.
+
+   The __syscall_cancel_arch function, used for all cancellable syscalls,
+   contains two extra markers, __syscall_cancel_arch_start and
+   __syscall_cancel_arch_end.  The former points to just before the initial
+   conditional branch that checks if the thread has received a cancellation
+   request, while former points to the instruction after the one responsible
+   to issue the syscall.
+
+   The function check if the program counter (PC) from ucontext_t CTX is
+   within the start and then end boundary from the __syscall_cancel_arch
+   bridge.  Return TRUE if the PC is within the boundary, meaning the
+   syscall does not have any side effects; or FALSE otherwise.  */
+
+static __always_inline bool
+cancellation_pc_check (void *ctx)
+{
+  /* Both are defined in syscall_cancel.S.  */
+  extern const char __syscall_cancel_arch_start[1];
+  extern const char __syscall_cancel_arch_end_sc[1];
+#if defined(USE_PPC_SVC) && defined(__powerpc64__)
+  extern const char __syscall_cancel_arch_end_svc[1];
+#endif
+
+  uintptr_t pc = sigcontext_get_pc (ctx);
+
+  return pc >= (uintptr_t) __syscall_cancel_arch_start
+#if defined(USE_PPC_SVC) && defined(__powerpc64__)
+	 && THREAD_GET_HWCAP() & PPC_FEATURE2_SCV
+	    ? pc < (uintptr_t) __syscall_cancel_arch_end_sc
+	    : pc < (uintptr_t) __syscall_cancel_arch_end_svc;
+#else
+	 && pc < (uintptr_t) __syscall_cancel_arch_end_sc;
+#endif
+}
+
+#endif