Author: bdragon
Date: Fri Jan 17 23:41:35 2020
New Revision: 356856
URL: https://svnweb.freebsd.org/changeset/base/356856

Log:
  [PowerPC] Save a dword in the powerpc64 signal trampoline
  
  In r291668, an instruction was added to sigcode64.S without the nop pad at
  the end being taken out.
  
  Due to alignment, this means that a dword is being wasted on the shared
  page for no reason.
  
  Take out this nop, and add some comments while I'm here.
  
  Reviewed by:  jhibbits
  Sponsored by: Tag1 Consulting, Inc.
  Differential Revision:        https://reviews.freebsd.org/D23055

Modified:
  head/sys/powerpc/powerpc/sigcode64.S

Modified: head/sys/powerpc/powerpc/sigcode64.S
==============================================================================
--- head/sys/powerpc/powerpc/sigcode64.S        Fri Jan 17 22:26:41 2020        
(r356855)
+++ head/sys/powerpc/powerpc/sigcode64.S        Fri Jan 17 23:41:35 2020        
(r356856)
@@ -63,9 +63,13 @@ CNAME(sigcode64_elfv2):
        addi    3,1,112+SF_UC           /* restore sp, and get &frame->sf_uc */
        li      0,SYS_sigreturn
        sc                              /* sigreturn(scp) */
+       /*
+        * If we get back to here, it means sigreturn failed.
+        * As such, we are now stuck in the wrong context.
+        * Exit immediately without touching the stack.
+        */
        li      0,SYS_exit
        sc                              /* exit(errno) */
-       nop                             /* align to doubleword */
 endsigcode64:
        
        .data
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