1From a6ff69873110c0a8ba6f7fd90532dbc11224828c Mon Sep 17 00:00:00 2001
2From: Bruno Haible <bruno@clisp.org>
3Date: Sun, 13 Mar 2022 15:04:06 +0100
4Subject: [PATCH] Add support for Linux/PowerPC (32-bit) with musl libc.
5
6Reported by Khem Raj <raj.khem@gmail.com> in
7<https://lists.gnu.org/archive/html/m4-patches/2022-03/msg00000.html>.
8
9* autogen.sh: Copy also musl.m4.
10* configure.ac: Invoke gl_MUSL_LIBC.
11* src/fault-linux-powerpc.h (SIGSEGV_FAULT_STACKPOINTER): In the 32-bit
12case, handle musl libc differently.
13* NEWS: Mention it.
14
15Upstream: https://git.savannah.gnu.org/gitweb/?p=libsigsegv.git;a=commit;h=a6ff69873110c0a8ba6f7fd90532dbc11224828c
16Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
17---
18 ChangeLog                 | 11 +++++++++++
19 NEWS                      |  4 ++++
20 autogen.sh                |  3 ++-
21 configure.ac              |  2 ++
22 src/fault-linux-powerpc.h | 27 ++++++++++++++++++++++-----
23 5 files changed, 41 insertions(+), 6 deletions(-)
24
25diff --git a/ChangeLog b/ChangeLog
26index c52b227..7c0a8fa 100644
27--- a/ChangeLog
28+++ b/ChangeLog
29@@ -1,3 +1,14 @@
30+2022-03-13  Bruno Haible  <bruno@clisp.org>
31+
32+	Add support for Linux/PowerPC (32-bit) with musl libc.
33+	Reported by Khem Raj <raj.khem@gmail.com> in
34+	<https://lists.gnu.org/archive/html/m4-patches/2022-03/msg00000.html>.
35+	* autogen.sh: Copy also musl.m4.
36+	* configure.ac: Invoke gl_MUSL_LIBC.
37+	* src/fault-linux-powerpc.h (SIGSEGV_FAULT_STACKPOINTER): In the 32-bit
38+	case, handle musl libc differently.
39+	* NEWS: Mention it.
40+
41 2022-01-07  Bruno Haible  <bruno@clisp.org>
42
43 	Prepare for version 2.14.
44diff --git a/NEWS b/NEWS
45index 4d012f8..82cc0f4 100644
46--- a/NEWS
47+++ b/NEWS
48@@ -1,3 +1,7 @@
49+New in 2.15:
50+
51+* Added support for Linux/PowerPC (32-bit) with musl libc.
52+
53 New in 2.14:
54
55 * Added support for 64-bit Cygwin.
56diff --git a/configure.ac b/configure.ac
57index e87f13b..164786f 100644
58--- a/configure.ac
59+++ b/configure.ac
60@@ -75,6 +75,8 @@ AC_MSG_RESULT([$sv_cv_host])
61 PLATFORM="$sv_cv_host"
62 AC_SUBST([PLATFORM])
63
64+gl_MUSL_LIBC
65+
66 dnl ========================== Done with PLATFORM ==========================
67
68
69diff --git a/src/fault-linux-powerpc.h b/src/fault-linux-powerpc.h
70index cba6ea7..b3f922a 100644
71--- a/src/fault-linux-powerpc.h
72+++ b/src/fault-linux-powerpc.h
73@@ -1,5 +1,5 @@
74 /* Fault handler information.  Linux/PowerPC version when it supports POSIX.
75-   Copyright (C) 2002, 2009, 2017  Bruno Haible <bruno@clisp.org>
76+   Copyright (C) 2002, 2009, 2017, 2022  Bruno Haible <bruno@clisp.org>
77
78    This program is free software: you can redistribute it and/or modify
79    it under the terms of the GNU General Public License as published by
80@@ -28,10 +28,27 @@
81 #if defined(__powerpc64__) || defined(_ARCH_PPC64) /* 64-bit */
82 # define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_mcontext.gp_regs[1]
83 #else /* 32-bit */
84-/* both should be equivalent */
85-# if 0
86-#  define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_mcontext.regs->gpr[1]
87+# if MUSL_LIBC
88+/* musl libc has a different structure of ucontext_t in
89+   musl/arch/powerpc/bits/signal.h.  */
90+/* The glibc comments say:
91+     "Different versions of the kernel have stored the registers on signal
92+      delivery at different offsets from the ucontext struct.  Programs should
93+      thus use the uc_mcontext.uc_regs pointer to find where the registers are
94+      actually stored."  */
95+#  if 0
96+#   define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_mcontext.gregs[1]
97+#  else
98+#   define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_regs->gregs[1]
99+#  endif
100 # else
101-#  define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_mcontext.uc_regs->gregs[1]
102+/* Assume the structure of ucontext_t in
103+   glibc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h.  */
104+/* Because of the union, both definitions should be equivalent.  */
105+#  if 0
106+#   define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_mcontext.regs->gpr[1]
107+#  else
108+#   define SIGSEGV_FAULT_STACKPOINTER  ((ucontext_t *) ucp)->uc_mcontext.uc_regs->gregs[1]
109+#  endif
110 # endif
111 #endif
112--
1132.17.1
114
115