Use %esi to store next ucp pointer. Mark end of stack by

setting %ebp to zero, this avoids new gdb to dump a weird
backtrace.

2 files changed, 4 insertions, 3 deletions

diff --git a/lib/libc/i386/gen/_ctx_start.S b/lib/libc/i386/gen/_ctx_start.S
index bfff53a..91a06b8 100644
--- a/lib/libc/i386/gen/_ctx_start.S
+++ b/lib/libc/i386/gen/_ctx_start.S
@@ -41,7 +41,7 @@ __FBSDID("$FreeBSD$");
 ENTRY(_ctx_start)
 	popl	%eax		/* get start function */
 	call	*%eax		/* call start function */
-	movl	%ebp, %esp	/*
+	movl	%esi, %esp	/*
 				 * setup stack for completion routine;
 				 * ucp is now at top of stack
 				 */
diff --git a/lib/libc/i386/gen/makecontext.c b/lib/libc/i386/gen/makecontext.c
index a6fc6ad..1154459 100644
--- a/lib/libc/i386/gen/makecontext.c
+++ b/lib/libc/i386/gen/makecontext.c
@@ -150,10 +150,11 @@ __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
 		 * wrapper.  Note that setcontext() pushes the return
 		 * address onto the top of the stack, so allow for this
 		 * by adjusting the stack downward 1 slot.  Also set
-		 * %ebp to point to the base of the stack where ucp
+		 * %esi to point to the base of the stack where ucp
 		 * is stored.
 		 */
-		ucp->uc_mcontext.mc_ebp = (int)argp;
+		ucp->uc_mcontext.mc_esi = (int)argp;
+		ucp->uc_mcontext.mc_ebp = 0;
 		ucp->uc_mcontext.mc_esp = (int)stack_top + sizeof(caddr_t);
 		ucp->uc_mcontext.mc_eip = (int)_ctx_start;
 	}