9b1167219a
When simulating arm code, the target program startup code (crt0) uses semihosting invocations to get the command line from the simulator. The simulator returns the command line and its size into the area passed in parameter. (ARM 32-bit specifications : http://infocenter.arm.com/help/topic/com.arm.doc.dui0058d/DUI0058.pdf chapter "5.4.19 SYS_GET_CMDLINE"). The memory area pointed by the semihosting register argument is located in .text section (usually not writtable (RX)). If we run this code on a simulator that respects this rights properties (qemu user-mode for instance), the command line will not be written to the .text program memory, in particular the length of the string. The program runs with an empty command line. This problem hasn't been seen earlier probably because qemu user-mode is not so much used, but this can happen with another simulator that refuse to write in a read-only segment. With this modification, the command line can be correctly passed to the target program. Changes: - libgloss/arm/crt0.S : Arguments passed to the AngelSWI_Reason_GetCmdLine semihosting invocation are placed into .data section instead of .text - libgloss/aarch64/crt0.S : Idem for aarch64 AngelSVC_Reason_GetCmdLine semihosting.
531 lines
13 KiB
ArmAsm
531 lines
13 KiB
ArmAsm
#include "newlib.h"
|
|
#include "arm.h"
|
|
#include "swi.h"
|
|
|
|
/* ANSI concatenation macros. */
|
|
#define CONCAT(a, b) CONCAT2(a, b)
|
|
#define CONCAT2(a, b) a ## b
|
|
|
|
#ifdef __USER_LABEL_PREFIX__
|
|
#define FUNCTION( name ) CONCAT (__USER_LABEL_PREFIX__, name)
|
|
#else
|
|
#error __USER_LABEL_PREFIX is not defined
|
|
#endif
|
|
|
|
#ifdef HAVE_INITFINI_ARRAY
|
|
#define _init __libc_init_array
|
|
#define _fini __libc_fini_array
|
|
#endif
|
|
|
|
#if defined(__ARM_EABI__) && defined(__thumb__) && !defined(__thumb2__)
|
|
/* For Thumb1 we need to force the architecture to be sure that we get the
|
|
correct attributes on the object file; otherwise the assembler will get
|
|
confused and mark the object as being v6T2. */
|
|
#if defined(__ARM_ARCH_4T__)
|
|
.arch armv4t
|
|
#elif defined(__ARM_ARCH_5T__) || defined(__ARM_ARCH_5TE__)
|
|
/* Nothing in this object requires higher than v5. */
|
|
.arch armv5t
|
|
#elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
|
|
|| defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) \
|
|
|| defined(__ARM_ARCH_6ZK__)
|
|
/* Nothing in this object requires higher than v6. */
|
|
.arch armv6
|
|
#elif defined(__ARM_ARCH_6M__)
|
|
#ifdef ARM_RDP_MONITOR
|
|
/* Object file uses SVC, so mark as v6s-m. */
|
|
.arch armv6s-m
|
|
#else
|
|
.arch armv6-m
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
/* .text is used instead of .section .text so it works with arm-aout too. */
|
|
.text
|
|
.syntax unified
|
|
#ifdef PREFER_THUMB
|
|
.thumb
|
|
.macro FUNC_START name
|
|
.global \name
|
|
.thumb_func
|
|
\name:
|
|
.endm
|
|
#else
|
|
.code 32
|
|
.macro FUNC_START name
|
|
.global \name
|
|
\name:
|
|
.endm
|
|
#endif
|
|
|
|
.macro indirect_call reg
|
|
#ifdef HAVE_CALL_INDIRECT
|
|
blx \reg
|
|
#else
|
|
mov lr, pc
|
|
mov pc, \reg
|
|
#endif
|
|
.endm
|
|
|
|
.align 0
|
|
|
|
FUNC_START _mainCRTStartup
|
|
FUNC_START _start
|
|
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
|
|
/* Annotation for EABI unwinding tables. */
|
|
.fnstart
|
|
#endif
|
|
|
|
/* __ARM_ARCH_PROFILE is defined from GCC 4.8 onwards, however __ARM_ARCH_7A
|
|
has been defined since 4.2 onwards, which is when v7-a support was added
|
|
and hence 'A' profile support was added in the compiler. Allow for this
|
|
file to be built with older compilers. We only call this for A profile
|
|
cores. */
|
|
#if defined (__ARM_ARCH_7A__) || (__ARM_ARCH_PROFILE == 'A')
|
|
/* The init hook does not use the stack and is called before the stack has been set up. */
|
|
#ifdef ARM_RDI_MONITOR
|
|
bl _rdimon_hw_init_hook
|
|
.weak FUNCTION (_rdimon_hw_init_hook)
|
|
#endif
|
|
#endif
|
|
|
|
/* Start by setting up a stack */
|
|
#ifdef ARM_RDP_MONITOR
|
|
/* Issue Demon SWI to read stack info */
|
|
swi SWI_GetEnv /* Returns command line in r0 */
|
|
mov sp,r1 /* and the highest memory address in r1 */
|
|
|
|
/* stack limit is at end of data */
|
|
/* allow slop for stack overflow handling and small frames */
|
|
#ifdef THUMB1_ONLY
|
|
ldr r0, .LC2
|
|
adds r0, #128
|
|
adds r0, #128
|
|
mov sl, r0
|
|
#else
|
|
ldr sl, .LC2
|
|
add sl, sl, #256
|
|
#endif
|
|
#else
|
|
#ifdef ARM_RDI_MONITOR
|
|
/* Issue Angel SWI to read stack info */
|
|
movs r0, #AngelSWI_Reason_HeapInfo
|
|
adr r1, .LC0 /* point at ptr to 4 words to receive data */
|
|
#ifdef THUMB_VXM
|
|
bkpt AngelSWI
|
|
#elif defined(__thumb2__)
|
|
/* We are in thumb mode for startup on armv7 architectures. */
|
|
AngelSWIAsm AngelSWI
|
|
#else
|
|
/* We are always in ARM mode for startup on pre armv7 archs. */
|
|
AngelSWIAsm AngelSWI_ARM
|
|
#endif
|
|
ldr r0, .LC0 /* point at values read */
|
|
|
|
/* Set __heap_limit. */
|
|
ldr r1, [r0, #4]
|
|
cmp r1, #0
|
|
beq .LC33
|
|
ldr r2, =__heap_limit
|
|
str r1, [r2]
|
|
.LC33:
|
|
ldr r1, [r0, #0]
|
|
cmp r1, #0
|
|
bne .LC32
|
|
/* If the heap base value [r0, #0] is 0 then the heap base is actually
|
|
at the end of program data (i.e. __end__). See:
|
|
http://infocenter.arm.com/help/topic/com.arm.doc.dui0471-/Bacbefaa.html
|
|
for more information. */
|
|
ldr r1, .LC31
|
|
str r1, [r0, #0]
|
|
.LC32:
|
|
ldr r1, [r0, #8]
|
|
ldr r2, [r0, #12]
|
|
/* We skip setting sp/sl if 0 returned from semihosting.
|
|
- According to semihosting docs, if 0 returned from semihosting,
|
|
the system was unable to calculate the real value, so it's ok
|
|
to skip setting sp/sl to 0 here.
|
|
- Considering M-profile processors, We might want to initialize
|
|
sp by the first entry of vector table and return 0 to SYS_HEAPINFO
|
|
semihosting call, which will be skipped here. */
|
|
cmp r1, #0
|
|
beq .LC26
|
|
mov sp, r1
|
|
.LC26:
|
|
cmp r2, #0
|
|
beq .LC27
|
|
/* allow slop for stack overflow handling and small frames */
|
|
#ifdef THUMB1_ONLY
|
|
adds r2, #128
|
|
adds r2, #128
|
|
mov sl, r2
|
|
#else
|
|
add sl, r2, #256
|
|
#endif
|
|
.LC27:
|
|
#else
|
|
/* Set up the stack pointer to a fixed value */
|
|
/* Changes by toralf:
|
|
- Allow linker script to provide stack via __stack symbol - see
|
|
defintion of .Lstack
|
|
- Provide "hooks" that may be used by the application to add
|
|
custom init code - see .Lhwinit and .Lswinit
|
|
- Go through all execution modes and set up stack for each of them.
|
|
Loosely based on init.s from ARM/Motorola example code.
|
|
Note: Mode switch via CPSR is not allowed once in non-privileged
|
|
mode, so we take care not to enter "User" to set up its sp,
|
|
and also skip most operations if already in that mode. */
|
|
|
|
ldr r3, .Lstack
|
|
cmp r3, #0
|
|
#ifdef __thumb2__
|
|
it eq
|
|
#endif
|
|
#ifdef THUMB1_ONLY
|
|
bne .LC28
|
|
ldr r3, .LC0
|
|
.LC28:
|
|
#else
|
|
ldreq r3, .LC0
|
|
#endif
|
|
/* Note: This 'mov' is essential when starting in User, and ensures we
|
|
always get *some* sp value for the initial mode, even if we
|
|
have somehow missed it below (in which case it gets the same
|
|
value as FIQ - not ideal, but better than nothing.) */
|
|
mov sp, r3
|
|
#ifdef PREFER_THUMB
|
|
/* XXX Fill in stack assignments for interrupt modes. */
|
|
#else
|
|
mrs r2, CPSR
|
|
tst r2, #0x0F /* Test mode bits - in User of all are 0 */
|
|
beq .LC23 /* "eq" means r2 AND #0x0F is 0 */
|
|
msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled */
|
|
mov sp, r3
|
|
sub sl, sp, #0x1000 /* This mode also has its own sl (see below) */
|
|
|
|
mov r3, sl
|
|
msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled */
|
|
mov sp, r3
|
|
sub r3, r3, #0x1000
|
|
|
|
msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled */
|
|
mov sp, r3
|
|
sub r3, r3, #0x1000
|
|
|
|
msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled */
|
|
mov sp, r3
|
|
sub r3, r3, #0x2000
|
|
|
|
msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled */
|
|
|
|
mov sp, r3
|
|
sub r3, r3, #0x8000 /* Min size 32k */
|
|
bic r3, r3, #0x00FF /* Align with current 64k block */
|
|
bic r3, r3, #0xFF00
|
|
|
|
str r3, [r3, #-4] /* Move value into user mode sp without */
|
|
ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm */
|
|
orr r2, r2, #0xC0 /* Back to original mode, presumably SVC, */
|
|
msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1 */
|
|
#endif
|
|
.LC23:
|
|
/* Setup a default stack-limit in-case the code has been
|
|
compiled with "-mapcs-stack-check". Hard-wiring this value
|
|
is not ideal, since there is currently no support for
|
|
checking that the heap and stack have not collided, or that
|
|
this default 64k is enough for the program being executed.
|
|
However, it ensures that this simple crt0 world will not
|
|
immediately cause an overflow event: */
|
|
#ifdef THUMB1_ONLY
|
|
movs r2, #64
|
|
lsls r2, r2, #10
|
|
subs r2, r3, r2
|
|
mov sl, r2
|
|
#else
|
|
sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl */
|
|
#endif
|
|
#endif
|
|
#endif
|
|
/* Zero the memory in the .bss section. */
|
|
movs a2, #0 /* Second arg: fill value */
|
|
mov fp, a2 /* Null frame pointer */
|
|
mov r7, a2 /* Null frame pointer for Thumb */
|
|
|
|
ldr a1, .LC1 /* First arg: start of memory block */
|
|
ldr a3, .LC2
|
|
subs a3, a3, a1 /* Third arg: length of block */
|
|
|
|
|
|
#if __thumb__ && !defined(PREFER_THUMB)
|
|
/* Enter Thumb mode.... */
|
|
add a4, pc, #1 /* Get the address of the Thumb block */
|
|
bx a4 /* Go there and start Thumb decoding */
|
|
|
|
.code 16
|
|
.global __change_mode
|
|
.thumb_func
|
|
__change_mode:
|
|
#endif
|
|
|
|
bl FUNCTION (memset)
|
|
#if !defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)
|
|
/* Changes by toralf: Taken from libgloss/m68k/crt0.S
|
|
* initialize target specific stuff. Only execute these
|
|
* functions it they exist.
|
|
*/
|
|
ldr r3, .Lhwinit
|
|
cmp r3, #0
|
|
beq .LC24
|
|
indirect_call r3
|
|
.LC24:
|
|
ldr r3, .Lswinit
|
|
cmp r3, #0
|
|
beq .LC25
|
|
indirect_call r3
|
|
|
|
.LC25:
|
|
movs r0, #0 /* no arguments */
|
|
movs r1, #0 /* no argv either */
|
|
#else
|
|
/* Need to set up standard file handles */
|
|
bl FUNCTION (initialise_monitor_handles)
|
|
|
|
#ifdef ARM_RDP_MONITOR
|
|
swi SWI_GetEnv /* sets r0 to point to the command line */
|
|
movs r1, r0
|
|
#else
|
|
movs r0, #AngelSWI_Reason_GetCmdLine
|
|
ldr r1, .LC30 /* Space for command line */
|
|
AngelSWIAsm AngelSWI
|
|
ldr r1, .LC30
|
|
ldr r1, [r1]
|
|
#endif
|
|
/* Parse string at r1 */
|
|
movs r0, #0 /* count of arguments so far */
|
|
/* Push a NULL argument onto the end of the list. */
|
|
#ifdef __thumb__
|
|
push {r0}
|
|
#else
|
|
stmfd sp!, {r0}
|
|
#endif
|
|
.LC10:
|
|
/* Skip leading blanks */
|
|
#ifdef __thumb__
|
|
ldrb r3, [r1]
|
|
adds r1, #1
|
|
#else
|
|
ldrb r3, [r1], #1
|
|
#endif
|
|
cmp r3, #0
|
|
beq .LC12
|
|
cmp r3, #' '
|
|
beq .LC10
|
|
|
|
/* See whether we are scanning a string */
|
|
cmp r3, #'"'
|
|
#ifdef __thumb__
|
|
beq .LC20
|
|
cmp r3, #'\''
|
|
bne .LC21
|
|
.LC20:
|
|
movs r2, r3
|
|
b .LC22
|
|
|
|
.LC21:
|
|
movs r2, #' ' /* terminator type */
|
|
subs r1, r1, #1 /* adjust back to point at start char */
|
|
.LC22:
|
|
#else
|
|
cmpne r3, #'\''
|
|
moveq r2, r3
|
|
movne r2, #' ' /* terminator type */
|
|
subne r1, r1, #1 /* adjust back to point at start char */
|
|
#endif
|
|
|
|
/* Stack a pointer to the current argument */
|
|
#ifdef __thumb__
|
|
push {r1}
|
|
#else
|
|
stmfd sp!, {r1}
|
|
#endif
|
|
adds r0, r0, #1
|
|
.LC11:
|
|
#ifdef __thumb__
|
|
ldrb r3, [r1]
|
|
adds r1, #1
|
|
#else
|
|
ldrb r3, [r1], #1
|
|
#endif
|
|
cmp r3, #0
|
|
beq .LC12
|
|
cmp r2, r3 /* reached terminator? */
|
|
bne .LC11
|
|
movs r2, #0
|
|
subs r3, r1, #1
|
|
strb r2, [r3] /* terminate the arg string */
|
|
b .LC10
|
|
|
|
.LC12:
|
|
mov r1, sp /* point at stacked arg pointers */
|
|
/* We've now got the stacked args in order reverse the */
|
|
#ifdef __thumb__
|
|
movs r2, r0
|
|
lsls r2, #2
|
|
add r2, sp
|
|
mov r3, sp
|
|
.LC15: cmp r2, r3
|
|
bls .LC14
|
|
subs r2, #4
|
|
ldr r4, [r2]
|
|
ldr r5, [r3]
|
|
str r5, [r2]
|
|
str r4, [r3]
|
|
adds r3, #4
|
|
b .LC15
|
|
.LC14:
|
|
/* Ensure doubleword stack alignment. */
|
|
mov r4, sp
|
|
movs r5, #7
|
|
bics r4, r5
|
|
mov sp, r4
|
|
#else
|
|
add r2, sp, r0, LSL #2 /* End of args */
|
|
mov r3, sp /* Start of args */
|
|
.LC13: cmp r2, r3
|
|
ldrhi r4,[r2, #-4] /* Reverse ends of list */
|
|
ldrhi r5, [r3]
|
|
strhi r5, [r2, #-4]!
|
|
strhi r4, [r3], #4
|
|
bhi .LC13
|
|
/* Ensure doubleword stack alignment. */
|
|
bic sp, sp, #7
|
|
#endif
|
|
#endif
|
|
|
|
#ifdef __USES_INITFINI__
|
|
/* Some arm/elf targets use the .init and .fini sections
|
|
to create constructors and destructors, and for these
|
|
targets we need to call the _init function and arrange
|
|
for _fini to be called at program exit. */
|
|
movs r4, r0
|
|
movs r5, r1
|
|
#ifdef _LITE_EXIT
|
|
/* Make reference to atexit weak to avoid unconditionally pulling in
|
|
support code. Refer to comments in __atexit.c for more details. */
|
|
.weak FUNCTION(atexit)
|
|
ldr r0, .Latexit
|
|
cmp r0, #0
|
|
beq .Lweak_atexit
|
|
#endif
|
|
ldr r0, .Lfini
|
|
bl FUNCTION (atexit)
|
|
.Lweak_atexit:
|
|
bl FUNCTION (_init)
|
|
movs r0, r4
|
|
movs r1, r5
|
|
#endif
|
|
bl FUNCTION (main)
|
|
|
|
bl FUNCTION (exit) /* Should not return. */
|
|
|
|
#if __thumb__ && !defined(PREFER_THUMB)
|
|
/* Come out of Thumb mode. This code should be redundant. */
|
|
|
|
mov a4, pc
|
|
bx a4
|
|
|
|
.code 32
|
|
.global change_back
|
|
change_back:
|
|
/* Halt the execution. This code should never be executed. */
|
|
/* With no debug monitor, this probably aborts (eventually).
|
|
With a Demon debug monitor, this halts cleanly.
|
|
With an Angel debug monitor, this will report 'Unknown SWI'. */
|
|
swi SWI_Exit
|
|
#endif
|
|
|
|
/* For Thumb, constants must be after the code since only
|
|
positive offsets are supported for PC relative addresses. */
|
|
|
|
.align 0
|
|
.LC0:
|
|
#ifdef ARM_RDI_MONITOR
|
|
.word HeapBase
|
|
#else
|
|
#ifndef ARM_RDP_MONITOR
|
|
/* Changes by toralf: Provide alternative "stack" variable whose value
|
|
may be defined externally; .Lstack will be used instead of .LC0 if
|
|
it points to a non-0 value. Also set up references to "hooks" that
|
|
may be used by the application to provide additional init code. */
|
|
|
|
#ifdef __pe__
|
|
.word 0x800000
|
|
#else
|
|
.word 0x80000 /* Top of RAM on the PIE board. */
|
|
#endif
|
|
.Lstack:
|
|
.word __stack
|
|
.Lhwinit:
|
|
.word FUNCTION (hardware_init_hook)
|
|
.Lswinit:
|
|
.word FUNCTION (software_init_hook)
|
|
|
|
/* Set up defaults for the above variables in the form of weak symbols
|
|
- so that application will link correctly, and get value 0 in
|
|
runtime (meaning "ignore setting") for the variables, when the user
|
|
does not provide the symbols. (The linker uses a weak symbol if,
|
|
and only if, a normal version of the same symbol isn't provided
|
|
e.g. by a linker script or another object file.) */
|
|
|
|
.weak __stack
|
|
.weak FUNCTION (hardware_init_hook)
|
|
.weak FUNCTION (software_init_hook)
|
|
#endif
|
|
|
|
#endif
|
|
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
|
|
/* Protect against unhandled exceptions. */
|
|
.cantunwind
|
|
.fnend
|
|
#endif
|
|
.LC1:
|
|
.word __bss_start__
|
|
.LC2:
|
|
.word __bss_end__
|
|
#ifdef __USES_INITFINI__
|
|
#ifdef _LITE_EXIT
|
|
.Latexit:
|
|
.word FUNCTION(atexit)
|
|
|
|
/* Weak reference _fini in case of lite exit. */
|
|
.weak FUNCTION(_fini)
|
|
#endif
|
|
.Lfini:
|
|
.word FUNCTION(_fini)
|
|
#endif
|
|
#ifdef ARM_RDI_MONITOR
|
|
.LC30:
|
|
.word AngelSWIArgs
|
|
.LC31:
|
|
.word __end__
|
|
|
|
/* Workspace for Angel calls. */
|
|
.data
|
|
/* Data returned by monitor SWI. */
|
|
.global __stack_base__
|
|
HeapBase: .word 0
|
|
HeapLimit: .word 0
|
|
__stack_base__: .word 0
|
|
StackLimit: .word 0
|
|
CommandLine: .space 256,0 /* Maximum length of 255 chars handled. */
|
|
AngelSWIArgs:
|
|
.word CommandLine
|
|
.word 255
|
|
#endif
|
|
|
|
#ifdef __pe__
|
|
.section .idata$3
|
|
.long 0,0,0,0,0,0,0,0
|
|
#endif
|