Bootloader cleanup (UNTESTED!)

- Clean up bootloader asm
- Remove fromflash.c - it's not worth doing in C, do it in ASM
- Clean up linker script
- Force use of symbol inside bootphase2 (otherwise linker
  garbage-collects it)
- Link bootloader with gcc instead of ld

bootrom/Makefile

@@ -7,7 +7,7 @@
 #-----------------------------------------------------------------------------
 
 # DO NOT use thumb mode in the phase 1 bootloader since that generates a section with glue code
-ARMSRC = fromflash.c 
+ARMSRC = 
 THUMBSRC = usb.c bootrom.c
 ASMSRC = ram-reset.s flash-reset.s
 
@@ -27,7 +27,7 @@ include ../common/Makefile.common
 all: $(OBJDIR)/bootrom.s19
 
 $(OBJDIR)/bootrom.elf: $(VERSIONOBJ) $(ASMOBJ) $(ARMOBJ) $(THUMBOBJ)
-	$(LD) -g -Tldscript-flash --oformat elf32-littlearm -Map=$(patsubst %.elf,%.map,$@) -o $@ $^
+	$(CC) $(LDFLAGS) -Wl,-T,ldscript-flash,-Map,$(patsubst %.elf,%.map,$@) -o $@ $^ $(LIBS)
 
 clean:
 	$(DELETE) $(OBJDIR)$(PATHSEP)*.o

bootrom/flash-reset.s

@@ -6,46 +6,48 @@
 @ Reset vector for running from FLASH
 @-----------------------------------------------------------------------------
 
-.extern CopyBootToRAM
-
 .section .startup,"ax"
-         .code 32
+
-         .align 0
+.arm
 
 .global flashstart
 flashstart:
-    b       Reset
+	b	reset
-    b       UndefinedInstruction
+	b	undefined_instruction
-    b       SoftwareInterrupt
+	b	software_interrupt
-    b       PrefetchAbort
+	b	prefetch_abort
-    b       DataAbort
+	b	data_abort
-    b       Reserved
+	b	. @reserved
-    b       Irq
+	b	irq
-    b       Fiq
+	b	fiq
 
-Reset:
+reset:
-    ldr     sp,     .stack_end	@ initialize stack pointer to top of RAM
+	ldr	sp, =_stack_end		@ initialize stack pointer to top of RAM
-    bl      CopyBootToRAM			@ copy bootloader to RAM (in case the
+
-    								@ user re-flashes the bootloader)
+	@ copy bootloader to RAM (in case the user re-flashes the bootloader)
-    ldr     r3,     .bootphase2_start	@ start address of RAM bootloader
+	ldr	r0, =__bootphase2_src_start__
+	ldr	r1, =__bootphase2_start__
+	ldr	r2, =__bootphase2_end__
+1:
+	ldr	r3, [r0], #4
+	str	r3, [r1], #4
+	cmp	r1, r2
+	blo	1b
+
+	ldr	r3, =ram_start		@ start address of RAM bootloader
 	bx	r3			@ jump to it
 
-	.stack_end:
+	.ltorg
-	.word _stack_end
-	.bootphase2_start:
-	.word __bootphase2_start__
 
-Fiq:
+undefined_instruction:
-    b       Fiq
+	b	.
-UndefinedInstruction:
+software_interrupt:
-    b       UndefinedInstruction
+	b	.
-SoftwareInterrupt:
+prefetch_abort:
-    b       SoftwareInterrupt
+	b	.
-PrefetchAbort:
+data_abort:
-    b       PrefetchAbort
+	b	.
-DataAbort:
+irq:
-    b       DataAbort
+	b	.
-Reserved:
+fiq:
-    b       Reserved
+	b	.
-Irq:
-    b       Irq

bootrom/fromflash.c

@@ -1,21 +0,0 @@
-//-----------------------------------------------------------------------------
-// This code is licensed to you under the terms of the GNU GPL, version 2 or,
-// at your option, any later version. See the LICENSE.txt file for the text of
-// the license.
-//-----------------------------------------------------------------------------
-// Helper function for launching the bootloader from FLASH
-//-----------------------------------------------------------------------------
-
-#include <proxmark3.h>
-
-extern char __bootphase2_src_start__, __bootphase2_start__, __bootphase2_end__;
-void __attribute__((section(".bootphase1"))) CopyBootToRAM(void)
-{
-	int i;
-
-	volatile uint32_t *s = (volatile uint32_t *)&__bootphase2_src_start__;
-	volatile uint32_t *d = (volatile uint32_t *)&__bootphase2_start__;
-	unsigned int l = (int)&__bootphase2_end__ - (int)&__bootphase2_start__;
-
-	for(i = 0; i < l/sizeof(uint32_t); i++) *d++ = *s++;
-}

bootrom/ldscript-flash

@@ -13,49 +13,42 @@ INCLUDE ../common/ldscript.common
 ENTRY(flashstart)
 SECTIONS
 {
-    . = 0;
-    
 	.bootphase1 : {
 		*(.startup)
-    	*(.bootphase1)
 
-    	/* It seems to be impossible to flush align a section at the
+		. = ALIGN(4);
-    	   end of a memory segment. Instead, we'll put the version_information
+		_version_information_start = .;
-    	   wherever the linker wants it, and then put a pointer to the start
-    	   of the version information at the end of the section.
-    	   -- Henryk Plötz <henryk@ploetzli.ch> 2009-08-28 */
-    	   
-    	_version_information_start = ABSOLUTE(.);
 		*(.version_information);
 
-	/* Why doesn't this work even though _bootphase1_version_pointer = 0x1001fc?
+		. = LENGTH(bootphase1) - 0x4;
-	  . = _bootphase1_version_pointer - ORIGIN(bootphase1); */
+		LONG(_version_information_start);
-	/* This works, apparently it fools the linker into accepting an absolute address */
-	. = _bootphase1_version_pointer - ORIGIN(bootphase1) + ORIGIN(bootphase1);
-    	LONG(_version_information_start)
 	} >bootphase1
 
-    __bootphase2_src_start__ = ORIGIN(bootphase2);
 	.bootphase2 : {
-    	__bootphase2_start__ = .;
 		*(.startphase2)
 		*(.text)
+		*(.text.*)
 		*(.eh_frame)
 		*(.glue_7)
 		*(.glue_7t)
 		*(.rodata)
+		*(.rodata.*)
 		*(.data)
-    	. = ALIGN( 32 / 8 );
+		*(.data.*)
-    	__bootphase2_end__ = .;
+		. = ALIGN(4);
 	} >ram AT>bootphase2
 
+	__bootphase2_src_start__ = LOADADDR(.bootphase2);
+	__bootphase2_start__ = ADDR(.bootphase2);
+	__bootphase2_end__ = __bootphase2_start__ + SIZEOF(.bootphase2);
+
 	.bss : {
 		__bss_start__ = .;
 		*(.bss)
-    } >ram
+		*(.bss.*)
-    
+		. = ALIGN(4);
-    . = ALIGN( 32 / 8 );
 		__bss_end__ = .;
+	} >ram
 
 	.commonarea (NOLOAD) : {
 		*(.commonarea)

bootrom/ram-reset.s

@@ -9,13 +9,12 @@
 .extern BootROM
 
 .section .startphase2,"ax"
-         .code 32
-         .align 0
 
-.global ramstart
+.arm
-ramstart:
+
-    ldr     sp,     .stack_end
+.global ram_start
+ram_start:
+	ldr	sp,     =_stack_end
 	bl	BootROM
 
-	.stack_end:
+	.ltorg
-	.word _stack_end