xtensa: merge crt1-*.S

We had two assembly files to prepare for entry into C domain,
one intended for the simulator and one intended for real boards.

- Both files merged into a single crt1.S for either simulated or real
  targets
- Extra logic to populate command line arguments from simulator removed,
  we don't use it.
- BSS zeroing logic from crt1-boards.S used
- Reference to missing reset-unneeded.S removed
- exit() implementation moved to fatal.c, now invokes a kernel panic
  if we are not running under the simulator

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2017-05-11 09:41:10 -07:00 committed by Anas Nashif
commit 51df312abc
4 changed files with 31 additions and 343 deletions

View file

@ -8,11 +8,9 @@ else
# Use our own routines implmented in assembly
obj-atomic=atomic.o
endif
obj-y = ${obj-atomic} cpu_idle.o fatal.o \
obj-y = ${obj-atomic} cpu_idle.o fatal.o crt1.o \
swap.o thread.o xt_zephyr.o xtensa_context.o xtensa_intr_asm.o \
xtensa_intr.o xtensa_vectors.o irq_manage.o
obj-$(CONFIG_IRQ_OFFLOAD) += irq_offload.o
obj-$(CONFIG_SIMULATOR_XTENSA) += crt1-sim.o
obj-$(CONFIG_BOARD_XTENSA) += crt1-boards.o
# Keep this last so that vague linking works
obj-y += sw_isr_table.o

View file

@ -1,247 +0,0 @@
/*
* Copyright (c) 2016 Cadence Design Systems, Inc.
* SPDX-License-Identifier: Apache-2.0
*/
/*
* For the Xtensa simulator target, this code sets up the C calling context
* and calls main() (via __clibrary_start).
* Control arrives here at _start from the reset vector or from crt0-app.S.
*/
#include <xtensa/simboard.h>
#include <xtensa/simcall.h>
#include <xtensa/coreasm.h>
/* Exports */
.global _start
.global __start
.global exit
/*
* Imports
* main from user application
* __stack from linker script (see LSP Ref Manual)
*/
.type _Cstart, @function
.type exit, @function
/* Macros to abstract away ABI differences */
#if __XTENSA_CALL0_ABI__
# define ENTRY
# define CALL call0
# define CALLX callx0
# define ARG1 a2 /* 1st outgoing call argument */
# define ARG2 a3 /* 2nd outgoing call argument */
# define ARG3 a4 /* 3rd outgoing call argument */
# define ARG4 a5 /* 4th outgoing call argument */
# define ARG5 a6 /* 5th outgoing call argument */
#else
# define ENTRY entry sp, 0x20
# define CALL call4
# define CALLX callx4
# define ARG1 a6 /* 1st outgoing call argument */
# define ARG2 a7 /* 2nd outgoing call argument */
# define ARG3 a8 /* 3rd outgoing call argument */
# define ARG4 a9 /* 4th outgoing call argument */
# define ARG5 a10 /* 5th outgoing call argument */
#endif
.data
.weak _start_envp /* allow overriding */
.align 4
_start_envp: .word 0 /* empty environ */
.text
.align 4
_start:
__start:
/*
* _start is typically NOT at the beginning of the text segment --
* it is always called from either the reset vector or other code
* that does equivalent initialization (such as crt0-app.S).
*
* Assumptions on entry to _start:
* - low (level-one) and medium priority interrupts are disabled
* via PS.INTLEVEL and/or INTENABLE (PS.INTLEVEL is expected to
* be zeroed, to potentially enable them, before calling main)
* - C calling context not initialized:
* - PS not initialized
* - SP not initialized
* - the following are initialized:
* - LITBASE, cache attributes, WindowBase, WindowStart,
* CPENABLE, FP's FCR and FSR, EXCSAVE[n]
* Keep a0 zero. It is used to initialize a few things.
* It is also the return address, where zero indicates
* that the frame used by _start is the bottommost frame.
*
*/
movi a0, 0 /* keep this register zero. */
#if XTOS_RESET_UNNEEDED
#include "reset-unneeded.S"
#endif
/*
* Initialize the stack pointer.
* See the "ABI and Software Conventions" chapter in the
* Xtensa ISA Reference manual for details.
*
* NOTE: Because the _start routine does not use any memory in its
* stack frame, and because all of its CALL instructions use a
* window size of 4, the stack frame for _start can be empty.
*/
movi sp, __stack
/*
* reserve stack space for
* - argv array
* - argument strings
*/
movi a2, SYS_iss_argv_size
simcall /* returns size of argv[] + its strings in a2 */
#if XCHAL_HAVE_PIF
/*
* The stack only needs 16-byte alignment. However, here we round up
* the argv size further to 128 byte multiples so that in most cases,
* variations in argv[0]'s path do not result in different stack
* allocation. Otherwise, such variations can impact execution timing
* (eg. due to cache effects etc) for the same code and data. If we
* have a PIF, it's more likely the extra required space is okay.
*/
addi a2, a2, 127
srli a2, a2, 7
slli a2, a2, 7
#else
/* Keep stack 16-byte aligned. */
addi a2, a2, 15
srli a2, a2, 4
slli a2, a2, 4
#endif
/*
* No need to use MOVSP because we have no caller (we're the
* base caller); in fact it's better not to use MOVSP in this
* context, to avoid unnecessary ALLOCA exceptions and copying
* from undefined memory:
* sub a3, sp, a2
* movsp sp, a3
*/
sub sp, sp, a2
/*
* Now that sp (a1) is set, we can set PS as per the application (user
* vector mode, enable interrupts, enable window exceptions if
* applicable).
*/
#if XCHAL_HAVE_EXCEPTIONS
# ifdef __XTENSA_CALL0_ABI__
/* PS.WOE = 0, PS.UM = 1, PS.EXCM = 0, PS.INTLEVEL = 0 */
movi a3, PS_UM
# else
/* PS.WOE = 1, PS.UM = 1, PS.EXCM = 0, PS.INTLEVEL = 0 */
movi a3, PS_UM|PS_WOE
# endif
wsr a3, PS
rsync
#endif
/*
* Do any initialization that affects the memory map, such as
* setting up TLB entries, that needs to be done before we can
* successfully clear BSS (e.g. if some BSS segments are in
* remapped areas).
*
* NOTE: This hook works where the reset vector does not unpack
* segments (see "ROM packing" in the LSP manual), or where
* unpacking of segments is not affected by memory remapping.
* If ROM unpacking is affected, TLB setup must be done in
* assembler from the reset vector.
*
* The __memmap_init() routine can be a C function, however it
* does not have BSS initialized! In particular, __memmap_init()
* cannot set BSS variables, i.e. uninitialized global variables
* (they'll be wiped out by the following BSS clear), nor can it
* assume they are yet initialized to zero.
*
* The __memmap_init() function is optional. It is marked as a
* weak symbol, so that it gets valued zero if not defined.
*/
.weak __memmap_init
movi a4, __memmap_init
beqz a4, 1f
CALLX a4
1:
/* The new ISS simcall only appeared after RB-2007.2: */
#if !XCHAL_HAVE_BOOTLOADER && \
(XCHAL_HW_MAX_VERSION > XTENSA_HWVERSION_RB_2007_2)
/* pre-LX2 cores only */
/*
* Clear the BSS (uninitialized data) segments.
* This code supports multiple zeroed sections (*.bss).
* For speed, we clear memory using an ISS simcall
* (see crt1-boards.S for more generic BSS clearing code).
*/
movi a6, _bss_table_start
movi a7, _bss_table_end
bgeu a6, a7, .Lnobss
.Lbssloop:
movi a2, SYS_memset
l32i a3, a6, 0 /* arg1 = fill start address */
movi a4, 0 /* arg2 = fill pattern */
l32i a5, a6, 4 /* get end address */
addi a6, a6, 8 /* next bss table entry */
sub a5, a5, a3 /* arg3 = fill size in bytes */
simcall /* memset(a3,a4,a5) */
bltu a6, a7, .Lbssloop /* loop until end of bss table */
.Lnobss:
#endif
/* Get argv with the arguments from the ISS */
mov a3, sp /* tell simcall where to write argv[] */
movi a2, SYS_iss_set_argv
simcall /* write argv[] array at a3 */
movi a2, SYS_iss_argc
simcall /* put argc in a2 */
/* Call: int _Cstart(); */
CALL _Cstart
/* The return value is the same register as the first outgoing
* argument.
*/
CALL exit
/* Does not return here. */
.size _start, . - _start
.align 4
exit:
ENTRY
mov a3, a2
movi a2, SYS_exit
simcall
.size exit, . - exit
/*
* Local Variables:
* mode:fundamental
* comment-start: "/* "
* comment-start-skip: "/* *"
* End:
*/

View file

@ -4,33 +4,26 @@
*/
/*
* For most hardware / boards, this code sets up the C calling context
* (setting up stack, PS, and clearing BSS) and jumps to __clibrary_start
* which sets up the C library, calls constructors and registers destructors,
* and calls main().
*
* Control arrives here at _start from the reset vector or from crt0-app.S.
*/
#include <xtensa/coreasm.h>
#include "xtos-internal.h"
#include <xtensa_rtos.h>
/* Exports */
.global _start
.global exit
/*
* Imports
* main from user application
* board_init board-specific (uart/mingloss/tinygloss.c)
* xthal_dcache_all_writeback from HAL library
* __stack from linker script (see LSP Ref Manual)
* _bss_table_start from linker script (see LSP Ref Manual)
* _bss_table_end from linker script (see LSP Ref Manual)
* _Cstart Entry point into Zephyr C domain
* __stack from linker script (see LSP Ref Manual)
*/
.type main, @function
.global __start
.type _Cstart, @function
/* Macros to abstract away ABI differences */
@ -52,14 +45,13 @@
# define ARG5 a10 /* 5th outgoing call argument */
#endif
/**************************************************************************/
.text
.align 4
_start:
__start:
/*
* _start is typically NOT at the beginning of the text segment --
* _start is typically NOT at the beginning of the text segment --
* it is always called from either the reset vector or other code
* that does equivalent initialization (such as crt0-app.S).
*
@ -77,17 +69,13 @@ _start:
* Keep a0 zero. It is used to initialize a few things.
* It is also the return address, where zero indicates
* that the frame used by _start is the bottommost frame.
*
*/
/* not needed for Xtensa TX */
#if !XCHAL_HAVE_HALT || !XCHAL_HAVE_BOOTLOADER
movi a0, 0 /* keep this register zero. */
#endif
#if XTOS_RESET_UNNEEDED && !XCHAL_HAVE_HALT
#include "reset-unneeded.S"
#endif
/*
* Initialize the stack pointer.
* See the "ABI and Software Conventions" chapter in the
@ -95,7 +83,7 @@ _start:
*
* NOTE: Because the _start routine does not use any memory in its
* stack frame, and because all of its CALL instructions use a
* window size of 4 (or zero), the stack frame for _start can be empty.
* window size of 4, the stack frame for _start can be empty.
*/
movi sp, __stack
@ -144,7 +132,6 @@ _start:
CALLX a4
1:
#if !XCHAL_HAVE_BOOTLOADER /* boot loader takes care of zeroing BSS */
# ifdef __XTENSA_CALL0_ABI__
@ -189,75 +176,11 @@ _start:
bltu a6, a7, .L0zte /* loop until end of table of *.bss sections */
.L3zte:
#endif
#endif /* !XCHAL_HAVE_BOOTLOADER */
/*
* We can now call C code, the C calling environment has been
* initialized.
*
* From this point on, we use ABI-specific macros to refer to
* registers a0 .. a15 (ARG#).
*/
#if XCHAL_HAVE_HALT
/*
* Assume minimalist environment for memory-constrained TX cores.
* No C library or board initialization, no parameters passed to main
* (assume declared as "void main(void)") and no call to exit().
*/
CALL main
halt
#else /* !HALT */
.type board_init, @function
.type exit, @function
/* Initialize the board (eg. UART, etc). */
CALL board_init
/* Call: int main(int argc, char ** argv, char ** environ); */
movi ARG1, _start_argc /* argc address */
movi ARG2, _start_argv /* argv = ["", 0] */
movi ARG3, _start_envp /* envp = [0] */
l32i ARG1, ARG1, 0 /* argc = 1 */
CALL main
/* The return value is the same register as the first
* outgoing argument.
*/
CALL exit /* exit with main's return value */
/* Does not return here. */
.data
/*
* Mark argc/argv/envp parameters as weak so that an external
* object file can override them.
*/
.weak _start_argc, _start_argv, _start_envp
.align 4
_start_argv:
.word _start_null /* empty program name */
_start_null:
_start_envp:
/* end of argv array, empty string, empty environ */
.word 0
_start_argc:
.word 1 /* one argument (program name) */
.text
#endif /* !HALT */
/* Enter C domain, never returns from here */
CALL _Cstart
.size _start, . - _start
.align 4
exit:
#if XCHAL_HAVE_INTERRUPTS
waiti 15
#endif
j exit
.size exit, . - exit

View file

@ -91,6 +91,7 @@ FUNC_NORETURN void _NanoFatalErrorHandler(unsigned int reason,
_SysFatalErrorHandler(reason, pEsf);
}
#ifdef CONFIG_PRINTK
static char *cause_str(unsigned int cause_code)
{
@ -198,8 +199,21 @@ FUNC_NORETURN void ReservedInterruptHandler(unsigned int intNo)
_NanoFatalErrorHandler(_NANO_ERR_RESERVED_IRQ, &_default_esf);
}
/* Implemented in Xtensa HAL */
extern FUNC_NORETURN void exit(int exit_code);
void exit(int return_code)
{
#ifdef XT_SIMULATOR
__asm__ (
"mov a3, %[code]\n\t"
"movi a2, %[call]\n\t"
"simcall\n\t"
:
: [code] "r" (return_code), [call] "I" (SYS_exit)
: "a3", "a2");
#else
printk("exit(%d)\n", return_code);
k_panic();
#endif
}
/**
*