Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.13-pull-request' into staging

# gpg: Signature made Thu 03 May 2018 22:38:35 BST
# gpg:                using RSA key F30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-2.13-pull-request:
  linux-user: remove useless padding in flock64 structure
  linux-user: introduce target_sigsp() and target_save_altstack()
  linux-user: ARM-FDPIC: Add support for signals for FDPIC targets
  linux-user: ARM-FDPIC: Add support of FDPIC for ARM.
  linux-user: ARM-FDPIC: Identify ARM FDPIC binaries
  Remove CONFIG_USE_FDPIC.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 19 insertions, 9 deletions

diff --git a/linux-user/sparc/signal.c b/linux-user/sparc/signal.c
index c823e61..45e922f 100644
--- a/linux-user/sparc/signal.c
+++ b/linux-user/sparc/signal.c
@@ -123,18 +123,28 @@ static inline abi_ulong get_sigframe(struct target_sigaction *sa,
                                      CPUSPARCState *env,
                                      unsigned long framesize)
 {
-    abi_ulong sp;
+    abi_ulong sp = get_sp_from_cpustate(env);
 
-    sp = env->regwptr[UREG_FP];
+    /*
+     * If we are on the alternate signal stack and would overflow it, don't.
+     * Return an always-bogus address instead so we will die with SIGSEGV.
+         */
+    if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) {
+            return -1;
+    }
 
     /* This is the X/Open sanctioned signal stack switching.  */
-    if (sa->sa_flags & TARGET_SA_ONSTACK) {
-        if (!on_sig_stack(sp)
-                && !((target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size) & 7)) {
-            sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
-        }
-    }
-    return sp - framesize;
+    sp = target_sigsp(sp, sa) - framesize;
+
+    /* Always align the stack frame.  This handles two cases.  First,
+     * sigaltstack need not be mindful of platform specific stack
+     * alignment.  Second, if we took this signal because the stack
+     * is not aligned properly, we'd like to take the signal cleanly
+     * and report that.
+     */
+    sp &= ~15UL;
+
+    return sp;
 }
 
 static int