From af856e3a857599bc2d2c2577a8064339778253b0 Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Thu, 16 Jul 2020 21:18:09 +0000
Subject: Make lazy binding work.

Committing on behalf of drahn@ who is a bit busy.
---
 libexec/ld.so/powerpc64/ldasm.S        | 19 ++++++++++---------
 libexec/ld.so/powerpc64/rtld_machine.c | 32 +++++++++++++++++++++++++++-----
 2 files changed, 37 insertions(+), 14 deletions(-)

(limited to 'libexec')

diff --git a/libexec/ld.so/powerpc64/ldasm.S b/libexec/ld.so/powerpc64/ldasm.S
index 5ed5c5ace27..f88031bc9bf 100644
--- a/libexec/ld.so/powerpc64/ldasm.S
+++ b/libexec/ld.so/powerpc64/ldasm.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldasm.S,v 1.2 2020/06/28 17:58:40 drahn Exp $ */
+/*	$OpenBSD: ldasm.S,v 1.3 2020/07/16 21:18:09 kettenis Exp $ */
 
 /*
  * Copyright (c) 1999 Dale Rahn
@@ -89,9 +89,10 @@ _dl_start:
 END(_dl_start)
 
 ENTRY(_dl_bind_start)
-	mflr	%r0
-	std	%r0,16(%r1)		# save	lr
-	std	%r2,24(%r1)		# save	toc
+	# r0 contains offset, do not overwrite 
+	# r2 ld.so toc is loaded on entry to this function.
+	mflr	%r12
+	std	%r12,16(%r1)		# save	lr
 
 	stdu	1,-104(%r1)
 
@@ -102,11 +103,11 @@ ENTRY(_dl_bind_start)
 	std	%r7,64(%r1)
 	std	%r8,72(%r1)
 	std	%r9,80(%r1)
-	std	%r10,96(%r1)
+	std	%r10,88(%r1)
 
-	mr	%r3,%r12		# obj
-	mr	%r4,%r11		# reloff
-	bl	_dl_bind		# _rtld_bind(obj, reloff)
+	mr	%r3,%r11		# obj
+	mr	%r4,%r0			# relidx
+	bl	_dl_bind		# _rtld_bind(obj, relidx)
 	mtctr	%r3
 	mr	%r12, %r3
 
@@ -117,7 +118,7 @@ ENTRY(_dl_bind_start)
 	ld	%r7,64(%r1)
 	ld	%r8,72(%r1)
 	ld	%r9,80(%r1)
-	ld	%r10,96(%r1)
+	ld	%r10,88(%r1)
 
 	addi	%r1,%r1,104
 
diff --git a/libexec/ld.so/powerpc64/rtld_machine.c b/libexec/ld.so/powerpc64/rtld_machine.c
index 4ea228e1fe9..08562960410 100644
--- a/libexec/ld.so/powerpc64/rtld_machine.c
+++ b/libexec/ld.so/powerpc64/rtld_machine.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtld_machine.c,v 1.2 2020/06/28 20:52:05 drahn Exp $ */
+/*	$OpenBSD: rtld_machine.c,v 1.3 2020/07/16 21:18:09 kettenis Exp $ */
 
 /*
  * Copyright (c) 1999 Dale Rahn
@@ -272,13 +272,35 @@ _dl_md_reloc_got(elf_object_t *object, int lazy)
 	if (object->Dyn.info[DT_PLTREL] != DT_RELA)
 		return 0;
 
-	fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
+	if (!lazy) {
+		fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
+	} else {
+		Elf_Addr *plt;
+		int numplt, i;
+
+		/* Relocate processor-specific tags. */
+		object->Dyn.info[DT_PROC(DT_PPC64_GLINK)] += object->obj_base;
+
+		if (object->Dyn.info[DT_PLTREL] != DT_RELA)
+			_dl_die(" bad relocation type PLTREL not RELA");
+
+		plt = (Elf_Addr *)
+		   (Elf_RelA *)(object->Dyn.info[DT_PLTGOT]);
+		numplt = object->Dyn.info[DT_PLTRELSZ] / sizeof(Elf_RelA);
+		plt[0] = (uint64_t)_dl_bind_start;
+		plt[1] = (uint64_t)object;
+		// offset 2 as first two entries are rtld parameters
+		for (i = 2; i < numplt+2; i++) {
+			plt[i] = object->Dyn.info[DT_PROC(DT_PPC64_GLINK)] +
+			     i*4 + 24;
+		}
+	}
 
 	return fails;
 }
 
 Elf_Addr
-_dl_bind(elf_object_t *object, int reloff)
+_dl_bind(elf_object_t *object, int relidx)
 {
 	const Elf_Sym *sym;
 	struct sym_res sr;
@@ -291,7 +313,7 @@ _dl_bind(elf_object_t *object, int reloff)
 		Elf_Addr newval;
 	} buf;
 
-	relas = (Elf_RelA *)(object->Dyn.info[DT_JMPREL] + reloff);
+	relas = ((Elf_RelA *)object->Dyn.info[DT_JMPREL]) + relidx;
 
 	sym = object->dyn.symtab;
 	sym += ELF_R_SYM(relas->r_info);
@@ -308,7 +330,7 @@ _dl_bind(elf_object_t *object, int reloff)
 		return buf.newval;
 
 	plttable = (Elf_Addr *)(Elf_RelA *)(object->Dyn.info[DT_PLTGOT]);
-	buf.param.kb_addr = &plttable[ reloff / sizeof(Elf_RelA) ];
+	buf.param.kb_addr = &plttable[relidx + 2];
 	buf.param.kb_size = sizeof(Elf_Addr);
 
 	{
-- 
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