From d857960c2adb4f01ce6ea2ad1fe7a7b476716dd2 Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Mon, 9 Jan 2023 13:52:42 +0000
Subject: [PATCH] Rewrite the hppa assembly code to avoid reads from .text, by
 using the standard PIC magic.  This makes the code similar to what we already
 use for rcrt0.o.  This makes it ready for execute-only.

Build C code using -fno-jump-tables to make it ready for execute-only.

ok deraadt@, miod@
---
 libexec/ld.so/hppa/Makefile.inc |  4 +--
 libexec/ld.so/hppa/ldasm.S      | 51 ++++++++++++---------------------
 2 files changed, 20 insertions(+), 35 deletions(-)

diff --git a/libexec/ld.so/hppa/Makefile.inc b/libexec/ld.so/hppa/Makefile.inc
index 9b81691c9ba..2797f45ac16 100644
--- a/libexec/ld.so/hppa/Makefile.inc
+++ b/libexec/ld.so/hppa/Makefile.inc
@@ -1,6 +1,6 @@
-#	$OpenBSD: Makefile.inc,v 1.7 2022/12/05 07:49:07 kettenis Exp $
+#	$OpenBSD: Makefile.inc,v 1.8 2023/01/09 13:52:42 kettenis Exp $
 
-CFLAGS += -fpic
+CFLAGS += -fpic -fno-jump-tables
 AFLAGS += -fpic
 LD_SCRIPT = ${.CURDIR}/${MACHINE_CPU}/ld.script
 
diff --git a/libexec/ld.so/hppa/ldasm.S b/libexec/ld.so/hppa/ldasm.S
index 4d19f9bfecb..6f52548caba 100644
--- a/libexec/ld.so/hppa/ldasm.S
+++ b/libexec/ld.so/hppa/ldasm.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldasm.S,v 1.25 2023/01/09 13:45:55 kettenis Exp $	*/
+/*	$OpenBSD: ldasm.S,v 1.26 2023/01/09 13:52:42 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2004 Michael Shalayeff
@@ -33,34 +33,27 @@
 #include <machine/vmparam.h>
 #undef	_LOCORE
 
+	.import	$global$, data
+
 ENTRY(_dl_start,32)
 	copy	r3, r1
 	copy	sp, r3
 	stwm	r1, HPPA_FRAME_SIZE+16*4(sp)
 
-	stw	%arg0, HPPA_FRAME_ARG(0)(r3)	/* ps_strings */
-
-#define	ADDR(s,r) \
-	bl	4, t1							!\
-	depi	0, 31, 2, t1	/* kill pl bits */			!\
-	b	s		/* cold brunch -- never done */		!\
-	ldw	0(t1), t2	/* cat(w,w1,w2{10},w2{0..9}) << 2 */	!\
-	extru	t2, 28, 10, t3	/* w2{0..9} */				!\
-	extru	t2, 26, 16, r	/* w1 */				!\
-	dep	t3, 31, 11, r						!\
-	extru,=	t2, 31, 1, r0	/* w */					!\
-	depi	1, 15, 1, r						!\
-	extru,=	t2, 29, 1, r0	/* w2{10} */				!\
-	depi	1, 21, 1, r						!\
-	sh2add	r, t1, r	/* plus the base */			!\
-	addi	8, r, r		/* bl target is -8 */
-
-	ADDR(_GLOBAL_OFFSET_TABLE_, r19)
-	ADDR(_DYNAMIC, arg2)
+	stw	arg0, HPPA_FRAME_ARG(0)(r3)	/* ps_strings */
+
+	bl	1f, r19
+	depi	0, 31, 2, r19
+1:	addil	L'$global$ - ($PIC_pcrel$0 - 8), r19
+	ldo	R'$global$ - ($PIC_pcrel$0 - 12)(r1), r19
+	bl	1f, arg2
+	depi	0, 31, 2, arg2
+1:	addil	L'_DYNAMIC - ($PIC_pcrel$0 - 8), arg2
+	ldo	R'_DYNAMIC - ($PIC_pcrel$0 - 12)(r1), arg2
 	stw	arg2, HPPA_FRAME_ARG(1)(r3)
 
 	/* make sure to get a fault until it's set proper */
-	ldi	-1, %dp
+	ldi	-1, dp
 
 	ldw	0(arg0), arg0
 	ldo	4(r3), arg1			/* dl_data */
@@ -79,7 +72,8 @@ ENTRY(_dl_start,32)
 	ldo	4(r3), arg3			/* dl_data */
 
 	ldw	HPPA_FRAME_ARG(0)(r3), arg0	/* ps_strings */
-	ADDR(_hppa_dl_dtors_plabel, arg1)
+	addil	LT'_dl_dtors_plabel, r19
+	ldw	RT'_dl_dtors_plabel(r1), arg1
 	ldw	0(arg1), arg1			/* cleanup */
 
 	ldo	HPPA_FRAME_SIZE(r3), sp
@@ -88,19 +82,10 @@ ENTRY(_dl_start,32)
 	ldwm	-HPPA_FRAME_SIZE(sp), r3
 EXIT(_dl_start)
 
-/*
- * void _hppa_dl_dtors(void);
- */
-ENTRY(_hppa_dl_dtors,0)
-	ADDR(_GLOBAL_OFFSET_TABLE_, r19)
-	b	_dl_dtors
-	nop
-EXIT(_hppa_dl_dtors)
-
 	.section .data
 	.align 4
-_hppa_dl_dtors_plabel:
-	.word P%_hppa_dl_dtors
+_dl_dtors_plabel:
+	.word P%_dl_dtors
 	.previous
 
 LEAF_ENTRY(_hppa_dl_set_dp)
-- 
2.20.1