From 6f2f006185cdeeda997d19d651379bfc6887e394 Mon Sep 17 00:00:00 2001 From: Joel Stanley Date: Mon, 6 Jun 2022 17:14:12 +0930 Subject: [PATCH] sigsegv: Add support for Linux/PowerPC (32-bit) with musl libc. Reported by Khem Raj in . * src/sigsegv.c (SIGSEGV_FAULT_STACKPOINTER): In the Linux/PowerPC 32-bit case, handle musl libc differently. * modules/sigsegv (Files): Add m4/musl.m4. (configure.ac): Invoke gl_MUSL_LIBC. Backported from http://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=2d830e4a792fcd9f614ed08a7f18584b8b21d23b Signed-off-by: Joel Stanley --- lib/sigsegv.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/lib/sigsegv.c b/lib/sigsegv.c index da70ffa5fda1..da64d7d0b617 100644 --- a/lib/sigsegv.c +++ b/lib/sigsegv.c @@ -227,11 +227,28 @@ int libsigsegv_version = LIBSIGSEGV_VERSION; # if defined __powerpc64__ || defined __powerpc64_elfv2__ /* 64-bit */ # define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.gp_regs[1] # else /* 32-bit */ -/* both should be equivalent */ -# if 0 -# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.regs->gpr[1] +# if MUSL_LIBC +/* musl libc has a different structure of ucontext_t in + musl/arch/powerpc/bits/signal.h. */ +/* The glibc comments say: + "Different versions of the kernel have stored the registers on signal + delivery at different offsets from the ucontext struct. Programs should + thus use the uc_mcontext.uc_regs pointer to find where the registers are + actually stored." */ +# if 0 +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.gregs[1] +# else +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_regs->gregs[1] +# endif # else -# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.uc_regs->gregs[1] +/* Assume the structure of ucontext_t in + glibc/sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h. */ +/* Because of the union, both definitions should be equivalent. */ +# if 0 +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.regs->gpr[1] +# else +# define SIGSEGV_FAULT_STACKPOINTER ((ucontext_t *) ucp)->uc_mcontext.uc_regs->gregs[1] +# endif # endif # endif -- 2.35.1