um: Use POSIX ucontext_t instead of struct ucontext

glibc 2.26 removed the 'struct ucontext' to "improve" POSIX compliance
and break programs, including User Mode Linux. Fix User Mode Linux
by using POSIX ucontext_t.

This fixes:

arch/um/os-Linux/signal.c: In function 'hard_handler':
arch/um/os-Linux/signal.c:163:22: error: dereferencing pointer to incomplete type 'struct ucontext'
  mcontext_t *mc = &uc->uc_mcontext;
arch/x86/um/stub_segv.c: In function 'stub_segv_handler':
arch/x86/um/stub_segv.c:16:13: error: dereferencing pointer to incomplete type 'struct ucontext'
          &uc->uc_mcontext);

Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: Richard Weinberger <richard@nod.at>

2 files changed, 2 insertions, 2 deletions

diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index a86d7cc2c2d8..a5c0c909c48b 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -159,7 +159,7 @@ static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = {
 
 static void hard_handler(int sig, siginfo_t *si, void *p)
 {
-        struct ucontext *uc = p;
+        ucontext_t *uc = p;
         mcontext_t *mc = &uc->uc_mcontext;
         unsigned long pending = 1UL << sig;
 
diff --git a/arch/x86/um/stub_segv.c b/arch/x86/um/stub_segv.c
index 1518d2805ae8..fd6825537b97 100644
--- a/arch/x86/um/stub_segv.c
+++ b/arch/x86/um/stub_segv.c
@@ -10,7 +10,7 @@
 void __attribute__ ((__section__ (".__syscall_stub")))
 stub_segv_handler(int sig, siginfo_t *info, void *p)
 {
-        struct ucontext *uc = p;
+        ucontext_t *uc = p;
 
         GET_FAULTINFO_FROM_MC(*((struct faultinfo *) STUB_DATA),
                               &uc->uc_mcontext);