From a10edf52674e1db9092ce4cc8312d5dbafed56d5 Mon Sep 17 00:00:00 2001
From: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Date: Sat, 25 Jun 2005 16:56:04 +0000
Subject: Hopefully fix PIE apps.

---
 libc/sysdeps/linux/arm/crt1.S | 82 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 70 insertions(+), 12 deletions(-)

(limited to 'libc/sysdeps/linux/arm/crt1.S')

diff --git a/libc/sysdeps/linux/arm/crt1.S b/libc/sysdeps/linux/arm/crt1.S
index 8ae897c06..86d6036d8 100644
--- a/libc/sysdeps/linux/arm/crt1.S
+++ b/libc/sysdeps/linux/arm/crt1.S
@@ -40,16 +40,48 @@
 		...
 					NULL
 */
+/*
+   For uClinux it looks like this:
+
+        argc            argument counter (integer)
+        argv            char *argv[]
+        envp            char *envp[]
+        argv[0]         program name (pointer)
+        argv[1...N]     program args (pointers)
+        argv[argc-1]    end of args (integer)
+	NULL
+        env[0...N]      environment variables (pointers)
+        NULL
+
+ARM register quick reference:
+
+    Name    Number       ARM Procedure Calling Standard Role
+
+    a1      r0           argument 1 / integer result / scratch register / argc
+    a2      r1           argument 2 / scratch register / argv
+    a3      r2           argument 3 / scratch register / envp
+    a4      r3           argument 4 / scratch register
+    v1      r4           register variable
+    v2      r5           register variable
+    v3      r6           register variable
+    v4      r7           register variable
+    v5      r8           register variable
+    sb/v6   r9           static base / register variable
+    sl/v7   r10          stack limit / stack chunk handle / reg. variable
+    fp      r11          frame pointer
+    ip      r12          scratch register / new-sb in inter-link-unit calls
+    sp      r13          lower end of current stack frame
+    lr      r14          link address / scratch register
+    pc      r15          program counter
+*/
 
 	.text
 	.globl _start
 	.type _start,#function
 _start:
-	/* Fetch address of fini */
-	ldr ip, =_fini
-
-	/* Clear the frame pointer since this is the outermost frame.  */
+	/* Clear the frame pointer and link register since this is the outermost frame.  */
 	mov fp, #0
+	mov lr, #0
 
 	/* Pop argc off the stack and save a pointer to argv */
 	ldr a2, [sp], #4
@@ -61,20 +93,46 @@ _start:
 	/* Push rtld_fini */
 	str a1, [sp, #-4]!
 
-	/* Set up the other arguments in registers */
-	ldr a1, =main
-	ldr a4, =_init
+#ifdef L_Scrt1
+	ldr sl, .L_GOT
+.L_GOT_OFF:
+	add sl, pc, sl
+
+	ldr ip, .L_GOT+4	/* _fini */
+	ldr a1, [sl, ip]
+	str a1, [sp, #-4]!	/* Push _fini */
 
+	ldr ip, .L_GOT+8	/* _init */
+	ldr a4, [sl, ip]
+	
+	ldr ip, .L_GOT+12	/* main */
+	ldr a1, [sl, ip]
+
+	/* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
+	/* Let the libc call main and exit with its return code.  */
+	b __uClibc_main(PLT)
+#else
+	/* Fetch address of fini */
+	ldr ip, =_fini
 	/* Push fini */
 	str ip, [sp, #-4]!
 
-	/* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
+	/* Set up the other arguments in registers */
+	ldr a1, =main
+	ldr a4, =_init
 
+	/* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
 	/* Let the libc call main and exit with its return code.  */
-	bl __uClibc_main
-
-	/* should never get here....*/
-	bl abort
+	b __uClibc_main
+#endif
+
+#ifdef L_Scrt1
+.L_GOT:
+	.word	_GLOBAL_OFFSET_TABLE_-(.L_GOT_OFF+8)
+	.word _fini(GOT)
+	.word _init(GOT)
+	.word main(GOT)
+#endif
 
 /* Define a symbol for the first piece of initialized data.  */
 	.data
-- 
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