atomic xtensa build fail

[hongshui3000]

Describe the bug
Not all xtensa architectures support the s32c1i and SCOMPARE1 registers
code:

#if defined(CONFIG_ATOMIC_OPERATIONS_BUILTIN)
/* Default.  See this file for the Doxygen reference: */
#include <sys/atomic_builtin.h>
#elif defined(CONFIG_ATOMIC_OPERATIONS_ARCH)-----------------------------------------------------------here
/* Some architectures need their own implementation */
# ifdef CONFIG_XTENSA
/* Not all Xtensa toolchains support GCC-style atomic intrinsics */
# include <arch/xtensa/atomic_xtensa.h>
# endif
#else
/* Generic-but-slow implementation based on kernel locking and syscalls */
#include <sys/atomic_c.h>
#endif

static ALWAYS_INLINE
atomic_val_t xtensa_cas(atomic_t *addr, atomic_val_t oldval,
			atomic_val_t newval)
{
	__asm__ volatile("wsr %1, SCOMPARE1; s32c1i %0, %2, 0" ---------------------------------------------here
			 : "+r"(newval), "+r"(oldval) : "r"(addr) : "memory");

	return newval; /* got swapped with the old memory by s32c1i */
}

log：

atomic_xtensa.h:35: Error: unknown opcode or format name 's32c1i'
atomic_xtensa.h:35: Error: invalid register 'SCOMPARE1' for 'wsr' instruction
atomic_xtensa.h:35: Error: unknown opcode or format name 's32c1i'
xt-xcc.exe ERROR:  C:/usr/xtensa/XtDevTools/install/tools/RI-2020.5-win32/XtensaTools/bin/xt-as.exe returned non-zero status 1

At least the code needs to be judged as follows,or distinguish the architecture used

if (XCHAL_HAVE_S32C1)
..............

The kconfig I saw opens the ATOMIC_OPERATIONS_ARCH configuration by default.

zephyr\arch\Kconfig：

config XTENSA
	bool
	select ARCH_IS_SET
	select HAS_DTS
	select USE_SWITCH
	select USE_SWITCH_SUPPORTED
	select ATOMIC_OPERATIONS_ARCH          -----------------------------------------------------------here
	help
	  Xtensa architecture

SECOND:
I found another problem when I enabled ATOMIC_OPERATIONS_BUILTIN

config SOC_SERIES_MYSOC
	bool "Xtensa hifi4 core"
	select XTENSA
	select XTENSA_HAL
	select ATOMIC_OPERATIONS_BUILTIN 

log:

In file included from E:/work/zephyr/include/sys/atomic.h:29,
                 from E:/work/zephyr/include/kernel_includes.h:21,
                 from E:/work/zephyr/include/kernel.h:17,
                 from E:/work/zephyr/include/init.h:11,
                 from E:/work/zephyr/include/device.h:29,
                 from E:/work/zephyr/kernel/include/kernel_offsets.h:6,
                 from E:/work/zephyr/arch/xtensa/core/offsets/offsets.c:7:
E:/work/zephyr/include/sys/atomic_builtin.h:304:29: error: syscalls/atomic.h: No such file or directory

Under the build directory I only found "ZCAN-sdk\build\zephyr\include\generated\syscalls\atomic_c.h" but no "atomic.h"
CONFIG_ATOMIC_OPERATIONS_C and CONFIG_ATOMIC_OPERATIONS_BUILTIN and CONFIG_ATOMIC_OPERATIONS_ARCH are enabled by me at the same time. but there is no warning that they cannot be enabled at the same time

code:

#ifdef CONFIG_ATOMIC_OPERATIONS_C
#include <syscalls/atomic.h>
#endif

My current change plan can build the code: del "select ATOMIC_OPERATIONS_ARCH" & CONFIG_XTENSA_NO_IPC=y & CONFIG_ATOMIC_OPERATIONS_C=y

zephyr\arch\Kconfig：

config XTENSA
	bool
	select ARCH_IS_SET
	select HAS_DTS
	select USE_SWITCH
	select USE_SWITCH_SUPPORTED
	help
	  Xtensa architecture

[andyross]

Does your platform really not have S32C1? That is the Xtensa atomic operations primitive, without it you have no hardware support and need to fall back to a much slower irq_lock() implementation in ATOMIC_OPERATIONS_C. ATOMIC_OPERATIONS_BUILTIN just falls back to the gcc implementations, which are essentially identical to our own and also based on S32C1I -- they won't work for you (the only reason we have our own is that older xcc toolchains don't have the gcc builtins).

As far as selecting this automatically based on core-isa.h constants, that would be nice but difficult, as kconfig sits upstream of the C compiler. You need the kconfig output header defined before you can build a C file against core-isa.h. The Zephyr model is that the platform layer decides on software configuration.

[hongshui3000]

@andyross
The biggest problem I encounter at the moment is that I have to change the code of Zephyr(Kconfig) in order to compile and pass.
If I change this, it will affect other platforms.
I cannot make ATOMIC_OPERATIONS_ARCH not selected through configuration?????
zephyr\arch\Kconfig：

config XTENSA
	bool
	select ARCH_IS_SET
	select HAS_DTS
	select USE_SWITCH
	select USE_SWITCH_SUPPORTED
        select ATOMIC_OPERATIONS_ARCH          -----------------------------------------------------------del here
	help
	  Xtensa architecture

as long as CONFIG_XTENSA is configured, select ATOMIC_OPERATIONS_ARCH will be selected. So my suggestion is not to choose here, but to give others the right to choose.
Otherwise, the unsupported S32C1 platform cannot be built through
This choice should not be determined by the architecture, it should be determined by the respective platform (soc or board).
Because the same architecture may not support ATOMIC_OPERATIONS_BUILTIN

[jcmvbkbc]

Does your platform really not have S32C1? That is the Xtensa atomic operations primitive

@andyross to be more precise that is one of the possible xtensa atomic operations primitive. There's also exclusive access option with l32ex/s32ex/getex/clrex opcodes and XCHAL_HAVE_EXCLUSIVE core-isa.h macro.