diff --git a/lib/libc/powerpc64/gen/_ctx_start.S b/lib/libc/powerpc64/gen/_ctx_start.S
index 4d5f106c96cb..250a9da3837f 100644
--- a/lib/libc/powerpc64/gen/_ctx_start.S
+++ b/lib/libc/powerpc64/gen/_ctx_start.S
@@ -37,11 +37,30 @@
 	ld	%r2,8(%r14)
 	ld	%r14,0(%r14)
 #else
+	mflr	%r0
+	/*
+	 * ABI hack:
+	 *
+	 * We are using an unusual calling convention here.
+	 * Our function is being called in the context of the start
+	 * function, as there may be stack parameters we need to pass
+	 * along.
+	 *
+	 * So we actually want to store things in the *parent* frame.
+	 */
+	ld	%r12, 0(%r1)
+	std	%r0, 16(%r12)
+	std	%r2, 24(%r12)
 	/* Load global entry point */
 	mr	%r12,%r14
 #endif
 	mtlr	%r14
 	blrl			/* branch to start function */
+
+	/* Return to parent frame and restore TOC. */
+	ld	%r1, 0(%r1)
+	ld	%r2, 24(%r1)
+
 	mr	%r3,%r15	/* pass pointer to ucontext as argument */
 	nop
 	bl	CNAME(_ctx_done) /* branch to ctxt completion func */
diff --git a/lib/libc/powerpc64/gen/makecontext.c b/lib/libc/powerpc64/gen/makecontext.c
index f5ecf3fa9ee6..5b1da36d5374 100644
--- a/lib/libc/powerpc64/gen/makecontext.c
+++ b/lib/libc/powerpc64/gen/makecontext.c
@@ -61,9 +61,9 @@ void
 __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
 {
 	mcontext_t *mc;
-	char *sp;
+	uintptr_t sp, backchain;
 	va_list ap;
-	int i, regargs, stackargs;
+	int i, regargs, stackargs, stackheader;
 
 	/* Sanity checks */
 	if ((ucp == NULL) || (argc < 0)
@@ -75,26 +75,41 @@ __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
 	}
 
 	/*
-	 * Since we are setting up a stack frame for an arbitrary function,
-	 * we *must* allocate a Parameter Save Area on top of the normal
-	 * stack frame header, as the callee may try and use it.
-	 *
-	 * The ELFv1 stack frame header is 6 dwords (48 bytes) and the
-	 * ELFv2 stack frame header is 4 dwords (32 bytes).
-	 *
-	 * Immediately following this is the Parameter Save Area, which
-	 * must be a minimum of 8 dwords when it exists.
+	 * Start by setting up an initial stack frame.
+	 * This frame will be used by _ctx_start() itself.
 	 */
-	stackargs = (argc > 8) ? argc - 8 : 0;
 #if !defined(_CALL_ELF) || _CALL_ELF == 1
-	sp = (char *) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size
-	    - sizeof(uintptr_t)*(6 + 8 + stackargs);
+	stackheader = 6; /* 48 bytes */
 #else
-	sp = (char *) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size
-	    - sizeof(uintptr_t)*(4 + 8 + stackargs);
+	stackheader = 4; /* 32 bytes */
 #endif
-	/* Ensure stack alignment. */
-	sp = (char *)((uintptr_t)sp & ~0x1f);
+	sp = ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size -
+	    sizeof(uintptr_t)*stackheader) & ~0x0f;
+
+	/* Initialize backchain */
+	*(uint64_t *)sp = 0x0;
+	backchain = sp;
+
+	/*
+	 * Set up the stack frame for the call to start.
+	 *
+	 * Despite the fact that we're actually branching to _ctx_start,
+	 * this stack frame is needed so we can pass stack arguments to
+	 * start.
+	 *
+	 * After _ctx_start does the call, it will discard this frame
+	 * and continue running on the initial stack frame.
+	 *
+	 * We are always allocating a Parameter Save Area here because
+	 * we do not know if start is varargs or not.
+	 */
+	stackargs = (argc > 8) ? argc - 8 : 0;
+
+	/* header + 8 dwords for the Parameter Save Area. */
+	sp = sp - sizeof(uintptr_t)*(stackheader + stackargs + 8);
+
+	/* Link to previous stack frame. */
+	*(uint64_t *)sp = backchain;
 
 	mc = &ucp->uc_mcontext;
 
@@ -123,11 +138,7 @@ __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
 		 * space for the callee to use. Skip an additional 8 dwords
 		 * past the end of the header to land on the correct slot.
 		 */
-#if !defined(_CALL_ELF) || _CALL_ELF == 1
-		argp = (uint64_t *)sp + 6 + 8;
-#else
-		argp = (uint64_t *)sp + 4 + 8;
-#endif
+		argp = (uint64_t *)sp + stackheader + 8;
 
 		for (i = 0; i < stackargs; i++)
 			*argp++ = va_arg(ap, uint64_t);
@@ -143,6 +154,8 @@ __makecontext(ucontext_t *ucp, void (*start)(void), int argc, ...)
 	mc->mc_srr0 = *(uintptr_t *)_ctx_start;
 #else
 	mc->mc_srr0 = (uintptr_t) _ctx_start;
+	/* ELFv2 ABI requirement. */
+	mc->mc_gpr[12] = (uintptr_t) _ctx_start;
 #endif
 	mc->mc_gpr[1] = (uintptr_t) sp;		/* new stack pointer */
 	mc->mc_gpr[14] = (uintptr_t) start;	/* r14 <- start */