sparc: Allow handling signals when stack is corrupted.

If we can't push the pending register windows onto the user's stack,
we disallow signal delivery even if the signal would be delivered on a
valid seperate signal stack.

Add a register window save area in the signal frame, and store any
unsavable windows there.

On sigreturn, if any windows are still queued up in the signal frame,
try to push them back onto the stack and if that fails we kill the
process immediately.

This allows the debug/tst-longjmp_chk2 glibc test case to pass.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/sparc/include/asm/sigcontext.h b/arch/sparc/include/asm/sigcontext.h
index a1607d180354..69914d748130 100644
--- a/arch/sparc/include/asm/sigcontext.h
+++ b/arch/sparc/include/asm/sigcontext.h
@@ -45,6 +45,19 @@ typedef struct {
         int                     si_mask;
 } __siginfo32_t;
 
+#define __SIGC_MAXWIN   7
+
+typedef struct {
+        unsigned long locals[8];
+        unsigned long ins[8];
+} __siginfo_reg_window;
+
+typedef struct {
+        int                     wsaved;
+        __siginfo_reg_window    reg_window[__SIGC_MAXWIN];
+        unsigned long           rwbuf_stkptrs[__SIGC_MAXWIN];
+} __siginfo_rwin_t;
+
 #ifdef CONFIG_SPARC64
 typedef struct {
         unsigned   int si_float_regs [64];
@@ -73,6 +86,7 @@ struct sigcontext {
                 unsigned long   ss_size;
         }                       sigc_stack;
         unsigned long           sigc_mask;
+        __siginfo_rwin_t *      sigc_rwin_save;
 };
 
 #else