From: Szabolcs Nagy <nsz@port70.net>
Date: Fri, 24 Aug 2018 23:11:59 +0000 (+0000)
Subject: rewrite __aeabi_read_tp in asm
X-Git-Tag: v1.1.20~19
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=056f9d818eaf1dbe9e9d63b64b109fd9b608fa36;p=oweals%2Fmusl.git

rewrite __aeabi_read_tp in asm

__aeabi_read_tp used to call c code, but that was incorrect as the
arm runtime abi specifies special pcs for this function: it is only
allowed to clobber r0, ip, lr and cpsr.

maintainer's note: the old code explicitly saved and restored all
general-purpose registers which are call-clobbered in the normal
calling convention, so it's unlikely that any real-world compilers
produced code that could break. however theoretically they could have
chosen to use floating point registers, in which case the caller's
values of those registers would be clobbered.
---

diff --git a/src/thread/arm/__aeabi_read_tp.s b/src/thread/arm/__aeabi_read_tp.s
index 9d0cd311..2585620c 100644
--- a/src/thread/arm/__aeabi_read_tp.s
+++ b/src/thread/arm/__aeabi_read_tp.s
@@ -2,7 +2,9 @@
 .global __aeabi_read_tp
 .type __aeabi_read_tp,%function
 __aeabi_read_tp:
-	push {r1,r2,r3,lr}
-	bl __aeabi_read_tp_c
-	pop {r1,r2,r3,lr}
-	bx lr
+	ldr r0,1f
+	add r0,r0,pc
+	ldr r0,[r0]
+2:	bx r0
+	.align 2
+1:	.word __a_gettp_ptr - 2b
diff --git a/src/thread/arm/__aeabi_read_tp_c.c b/src/thread/arm/__aeabi_read_tp_c.c
deleted file mode 100644
index 0c56d613..00000000
--- a/src/thread/arm/__aeabi_read_tp_c.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include "pthread_impl.h"
-#include <stdint.h>
-
-__attribute__((__visibility__("hidden")))
-void *__aeabi_read_tp_c(void)
-{
-	return TP_ADJ(__pthread_self());
-}