From c5e34dabbb47d8e97a4deccbb421e0cd93c0094b Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Fri, 26 Jul 2013 01:49:14 -0400
Subject: new mostly-C crt1 implementation

the only immediate effect of this commit is enabling PIE support on
some archs that did not previously have any Scrt1.s, since the
existing asm files for crt1 override this C code. so some of the
crt_arch.h files committed are only there for the sake of documenting
what their archs "would do" if they used the new C-based crt1.

the expectation is that new archs should use this new system rather
than using heavy asm for crt1. aside from being easier and less
error-prone, it also ensures that PIE support is available immediately
(since Scrt1.o is generated from the same C source, using -fPIC)
rather than having to be added as an afterthought in the porting
process.
---
 arch/arm/crt_arch.h        |  9 +++++++++
 arch/i386/crt_arch.h       | 13 +++++++++++++
 arch/microblaze/crt_arch.h | 11 +++++++++++
 arch/mips/crt_arch.h       | 21 +++++++++++++++++++++
 arch/powerpc/crt_arch.h    | 12 ++++++++++++
 arch/x86_64/crt_arch.h     |  9 +++++++++
 6 files changed, 75 insertions(+)
 create mode 100644 arch/arm/crt_arch.h
 create mode 100644 arch/i386/crt_arch.h
 create mode 100644 arch/microblaze/crt_arch.h
 create mode 100644 arch/mips/crt_arch.h
 create mode 100644 arch/powerpc/crt_arch.h
 create mode 100644 arch/x86_64/crt_arch.h

(limited to 'arch')

diff --git a/arch/arm/crt_arch.h b/arch/arm/crt_arch.h
new file mode 100644
index 00000000..979fb081
--- /dev/null
+++ b/arch/arm/crt_arch.h
@@ -0,0 +1,9 @@
+__asm__("\
+.global _start \n\
+_start: \n\
+	mov fp, #0 \n\
+	mov lr, #0 \n\
+	mov a1, sp \n\
+	and sp, sp, #-16 \n\
+	bl __cstart \n\
+");
diff --git a/arch/i386/crt_arch.h b/arch/i386/crt_arch.h
new file mode 100644
index 00000000..ae694f99
--- /dev/null
+++ b/arch/i386/crt_arch.h
@@ -0,0 +1,13 @@
+__asm__("\
+.text \n\
+.global _start \n\
+_start: \n\
+	xor %ebp,%ebp \n\
+	mov %esp,%eax \n\
+	and $-16,%esp \n\
+	push %eax \n\
+	push %eax \n\
+	push %eax \n\
+	push %eax \n\
+	call __cstart \n\
+");
diff --git a/arch/microblaze/crt_arch.h b/arch/microblaze/crt_arch.h
new file mode 100644
index 00000000..8917c695
--- /dev/null
+++ b/arch/microblaze/crt_arch.h
@@ -0,0 +1,11 @@
+__asm__("\
+.global _start \n\
+.align  2 \n\
+_start: \n\
+	add r19, r0, r0 \n\
+	ori r5, r1, 0 \n\
+	andi r1, r1, -8 \n\
+	addik r1, r1, -8 \n\
+	bri __cstart \n\
+	nop \n\
+");
diff --git a/arch/mips/crt_arch.h b/arch/mips/crt_arch.h
new file mode 100644
index 00000000..d4ae52d1
--- /dev/null
+++ b/arch/mips/crt_arch.h
@@ -0,0 +1,21 @@
+__asm__("\n\
+.set push\n\
+.set noreorder\n\
+.global __start\n\
+.global _start\n\
+.type   __start, @function\n\
+.type   _start, @function\n\
+__start:\n\
+_start:\n\
+	bal 1f \n\
+	move $fp, $0 \n\
+2:	.gpword 2b \n\
+1:	lw $gp, 0($ra) \n\
+	subu $gp, $ra, $gp \n\
+	move $4, $sp \n\
+	subu $sp, $sp, 16 \n\
+	and $sp, $sp, -8 \n\
+	lw $25, %call16(__cstart)($gp) \n\
+	jalr $25 \n\
+	nop \n\
+.set pop");
diff --git a/arch/powerpc/crt_arch.h b/arch/powerpc/crt_arch.h
new file mode 100644
index 00000000..8cc53d98
--- /dev/null
+++ b/arch/powerpc/crt_arch.h
@@ -0,0 +1,12 @@
+__asm__("\
+.global _start \n\
+.type   _start, %function \n\
+_start: \n\
+	mr 3, 1 \n\
+	clrrwi 1, 1, 4 \n\
+	li 0, 0 \n\
+	stwu 1, -16(1) \n\
+	mtlr 0 \n\
+	stw 0, 0(1) \n\
+	bl __cstart \n\
+");        
diff --git a/arch/x86_64/crt_arch.h b/arch/x86_64/crt_arch.h
new file mode 100644
index 00000000..db692950
--- /dev/null
+++ b/arch/x86_64/crt_arch.h
@@ -0,0 +1,9 @@
+__asm__("\
+.text \n\
+.global _start \n\
+_start: \n\
+	xor %rbp,%rbp \n\
+	mov %rsp,%rdi \n\
+	andq $-16,%rsp \n\
+	call __cstart \n\
+");
-- 
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