xtensa: implement call0 ABI support in assembly (0b537257) · Commits · EulixOS / Software / Kernel

arch/xtensa/boot/boot-redboot/bootstrap.S

+36 −32

Original line number	Original line	Diff line number	Diff line
	@@ -3,6 +3,7 @@
	#include <asm/regs.h>		#include <asm/regs.h>
	#include <asm/asmmacro.h>		#include <asm/asmmacro.h>
	#include <asm/cacheasm.h>		#include <asm/cacheasm.h>
			#include <asm/processor.h>
	/*		/*
	* RB-Data: RedBoot data/bss		* RB-Data: RedBoot data/bss
	* P: Boot-Parameters		* P: Boot-Parameters
	@@ -36,7 +37,7 @@
	.globl __start		.globl __start
	/* this must be the first byte of the loader! */		/* this must be the first byte of the loader! */
	__start:		__start:
	entry sp, 32 # we do not intend to return		abi_entry(32) # we do not intend to return
	_call0 _start		_call0 _start
	__start_a0:		__start_a0:
	.align 4		.align 4
	@@ -62,10 +63,12 @@ _start:
	wsr a4, windowstart		wsr a4, windowstart
	rsync		rsync

	movi a4, 0x00040000		movi a4, KERNEL_PS_WOE_MASK
	wsr a4, ps		wsr a4, ps
	rsync		rsync

			KABI_C0 mov abi_saved0, abi_arg0

	/* copy the loader to its address		/* copy the loader to its address
	* Note: The loader itself is a very small piece, so we assume we		* Note: The loader itself is a very small piece, so we assume we
	* don't partially overlap. We also assume (even more important)		* don't partially overlap. We also assume (even more important)
	@@ -168,52 +171,52 @@ _reloc:

	movi a3, __image_load		movi a3, __image_load
	sub a4, a3, a4		sub a4, a3, a4
	add a8, a0, a4		add abi_arg2, a0, a4

	# a1 Stack		# a1 Stack
	# a8(a4) Load address of the image		# a8(a4) Load address of the image

	movi a6, _image_start		movi abi_arg0, _image_start
	movi a10, _image_end		movi abi_arg4, _image_end
	movi a7, 0x1000000		movi abi_arg1, 0x1000000
	sub a11, a10, a6		sub abi_tmp0, abi_arg4, abi_arg0
	movi a9, complen		movi abi_arg3, complen
	s32i a11, a9, 0		s32i abi_tmp0, abi_arg3, 0

	movi a0, 0		movi a0, 0

	# a6 destination		# abi_arg0 destination
	# a7 maximum size of destination		# abi_arg1 maximum size of destination
	# a8 source		# abi_arg2 source
	# a9 ptr to length		# abi_arg3 ptr to length

	.extern gunzip		.extern gunzip
	movi a4, gunzip		movi abi_tmp0, gunzip
	beqz a4, 1f		beqz abi_tmp0, 1f

	callx4 a4		abi_callx abi_tmp0

	j 2f		j 2f


	# a6 destination start		# abi_arg0 destination start
	# a7 maximum size of destination		# abi_arg1 maximum size of destination
	# a8 source start		# abi_arg2 source start
	# a9 ptr to length		# abi_arg3 ptr to length
	# a10 destination end		# abi_arg4 destination end

	1:		1:
	l32i a9, a8, 0		l32i abi_tmp0, abi_arg2, 0
	l32i a11, a8, 4		l32i abi_tmp1, abi_arg2, 4
	s32i a9, a6, 0		s32i abi_tmp0, abi_arg0, 0
	s32i a11, a6, 4		s32i abi_tmp1, abi_arg0, 4
	l32i a9, a8, 8		l32i abi_tmp0, abi_arg2, 8
	l32i a11, a8, 12		l32i abi_tmp1, abi_arg2, 12
	s32i a9, a6, 8		s32i abi_tmp0, abi_arg0, 8
	s32i a11, a6, 12		s32i abi_tmp1, abi_arg0, 12
	addi a6, a6, 16		addi abi_arg0, abi_arg0, 16
	addi a8, a8, 16		addi abi_arg2, abi_arg2, 16
	blt a6, a10, 1b		blt abi_arg0, abi_arg4, 1b


	/* jump to the kernel */		/* jump to the kernel */
	@@ -230,6 +233,7 @@ _reloc:

	# a2 Boot parameter list		# a2 Boot parameter list

			KABI_C0 mov abi_arg0, abi_saved0
	movi a0, _image_start		movi a0, _image_start
	jx a0		jx a0

arch/xtensa/kernel/entry.S

+135 −74

Original line number	Original line	Diff line number	Diff line
	@@ -158,6 +158,7 @@ _user_exception:
	/* Rotate ws so that the current windowbase is at bit0. */		/* Rotate ws so that the current windowbase is at bit0. */
	/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */		/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */

			#if defined(USER_SUPPORT_WINDOWED)
	rsr a2, windowbase		rsr a2, windowbase
	rsr a3, windowstart		rsr a3, windowstart
	ssr a2		ssr a2
	@@ -167,24 +168,33 @@ _user_exception:
	src a2, a3, a2		src a2, a3, a2
	srli a2, a2, 32-WSBITS		srli a2, a2, 32-WSBITS
	s32i a2, a1, PT_WMASK # needed for restoring registers		s32i a2, a1, PT_WMASK # needed for restoring registers
			#else
			movi a2, 0
			movi a3, 1
			s32i a2, a1, PT_WINDOWBASE
			s32i a3, a1, PT_WINDOWSTART
			s32i a3, a1, PT_WMASK
			#endif

	/* Save only live registers. */		/* Save only live registers. */

	_bbsi.l a2, 1, 1f		UABI_W _bbsi.l a2, 1, 1f
	s32i a4, a1, PT_AREG4		s32i a4, a1, PT_AREG4
	s32i a5, a1, PT_AREG5		s32i a5, a1, PT_AREG5
	s32i a6, a1, PT_AREG6		s32i a6, a1, PT_AREG6
	s32i a7, a1, PT_AREG7		s32i a7, a1, PT_AREG7
	_bbsi.l a2, 2, 1f		UABI_W _bbsi.l a2, 2, 1f
	s32i a8, a1, PT_AREG8		s32i a8, a1, PT_AREG8
	s32i a9, a1, PT_AREG9		s32i a9, a1, PT_AREG9
	s32i a10, a1, PT_AREG10		s32i a10, a1, PT_AREG10
	s32i a11, a1, PT_AREG11		s32i a11, a1, PT_AREG11
	_bbsi.l a2, 3, 1f		UABI_W _bbsi.l a2, 3, 1f
	s32i a12, a1, PT_AREG12		s32i a12, a1, PT_AREG12
	s32i a13, a1, PT_AREG13		s32i a13, a1, PT_AREG13
	s32i a14, a1, PT_AREG14		s32i a14, a1, PT_AREG14
	s32i a15, a1, PT_AREG15		s32i a15, a1, PT_AREG15

			#if defined(USER_SUPPORT_WINDOWED)
	_bnei a2, 1, 1f # only one valid frame?		_bnei a2, 1, 1f # only one valid frame?

	/* Only one valid frame, skip saving regs. */		/* Only one valid frame, skip saving regs. */
	@@ -239,7 +249,7 @@ _user_exception:
	rsync		rsync

	/* We are back to the original stack pointer (a1) */		/* We are back to the original stack pointer (a1) */
			#endif
	2: /* Now, jump to the common exception handler. */		2: /* Now, jump to the common exception handler. */

	j common_exception		j common_exception
	@@ -295,6 +305,7 @@ _kernel_exception:
	s32i a3, a1, PT_SAR		s32i a3, a1, PT_SAR
	s32i a2, a1, PT_ICOUNTLEVEL		s32i a2, a1, PT_ICOUNTLEVEL

			#if defined(__XTENSA_WINDOWED_ABI__)
	/* Rotate ws so that the current windowbase is at bit0. */		/* Rotate ws so that the current windowbase is at bit0. */
	/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */		/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */

	@@ -305,27 +316,28 @@ _kernel_exception:
	src a2, a3, a2		src a2, a3, a2
	srli a2, a2, 32-WSBITS		srli a2, a2, 32-WSBITS
	s32i a2, a1, PT_WMASK # needed for kernel_exception_exit		s32i a2, a1, PT_WMASK # needed for kernel_exception_exit
			#endif

	/* Save only the live window-frame */		/* Save only the live window-frame */

	_bbsi.l a2, 1, 1f		KABI_W _bbsi.l a2, 1, 1f
	s32i a4, a1, PT_AREG4		s32i a4, a1, PT_AREG4
	s32i a5, a1, PT_AREG5		s32i a5, a1, PT_AREG5
	s32i a6, a1, PT_AREG6		s32i a6, a1, PT_AREG6
	s32i a7, a1, PT_AREG7		s32i a7, a1, PT_AREG7
	_bbsi.l a2, 2, 1f		KABI_W _bbsi.l a2, 2, 1f
	s32i a8, a1, PT_AREG8		s32i a8, a1, PT_AREG8
	s32i a9, a1, PT_AREG9		s32i a9, a1, PT_AREG9
	s32i a10, a1, PT_AREG10		s32i a10, a1, PT_AREG10
	s32i a11, a1, PT_AREG11		s32i a11, a1, PT_AREG11
	_bbsi.l a2, 3, 1f		KABI_W _bbsi.l a2, 3, 1f
	s32i a12, a1, PT_AREG12		s32i a12, a1, PT_AREG12
	s32i a13, a1, PT_AREG13		s32i a13, a1, PT_AREG13
	s32i a14, a1, PT_AREG14		s32i a14, a1, PT_AREG14
	s32i a15, a1, PT_AREG15		s32i a15, a1, PT_AREG15

			#ifdef __XTENSA_WINDOWED_ABI__
	_bnei a2, 1, 1f		_bnei a2, 1, 1f

	/* Copy spill slots of a0 and a1 to imitate movsp		/* Copy spill slots of a0 and a1 to imitate movsp
	* in order to keep exception stack continuous		* in order to keep exception stack continuous
	*/		*/
	@@ -333,6 +345,7 @@ _kernel_exception:
	l32i a0, a1, PT_SIZE + 4		l32i a0, a1, PT_SIZE + 4
	s32e a3, a1, -16		s32e a3, a1, -16
	s32e a0, a1, -12		s32e a0, a1, -12
			#endif
	1:		1:
	l32i a0, a1, PT_AREG0 # restore saved a0		l32i a0, a1, PT_AREG0 # restore saved a0
	wsr a0, depc		wsr a0, depc
	@@ -419,16 +432,16 @@ common_exception:
	movi a3, LOCKLEVEL		movi a3, LOCKLEVEL

	.Lexception:		.Lexception:
	movi a0, PS_WOE_MASK		KABI_W movi a0, PS_WOE_MASK
	or a3, a3, a0		KABI_W or a3, a3, a0
	#else		#else
	addi a2, a2, -EXCCAUSE_LEVEL1_INTERRUPT		addi a2, a2, -EXCCAUSE_LEVEL1_INTERRUPT
	movi a0, LOCKLEVEL		movi a0, LOCKLEVEL
	extui a3, a3, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH		extui a3, a3, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH
	# a3 = PS.INTLEVEL		# a3 = PS.INTLEVEL
	moveqz a3, a0, a2 # a3 = LOCKLEVEL iff interrupt		moveqz a3, a0, a2 # a3 = LOCKLEVEL iff interrupt
	movi a2, PS_WOE_MASK		KABI_W movi a2, PS_WOE_MASK
	or a3, a3, a2		KABI_W or a3, a3, a2
	rsr a2, exccause		rsr a2, exccause
	#endif		#endif

	@@ -461,14 +474,14 @@ common_exception:
	*/		*/

	rsr a4, excsave1		rsr a4, excsave1
	mov a6, a1 # pass stack frame
	mov a7, a2 # pass EXCCAUSE
	addx4 a4, a2, a4		addx4 a4, a2, a4
	l32i a4, a4, EXC_TABLE_DEFAULT # load handler		l32i a4, a4, EXC_TABLE_DEFAULT # load handler
			mov abi_arg1, a2 # pass EXCCAUSE
			mov abi_arg0, a1 # pass stack frame

	/* Call the second-level handler */		/* Call the second-level handler */

	callx4 a4		abi_callx a4

	/* Jump here for exception exit */		/* Jump here for exception exit */
	.global common_exception_return		.global common_exception_return
	@@ -482,15 +495,15 @@ common_exception_return:
	1:		1:
	irq_save a2, a3		irq_save a2, a3
	#ifdef CONFIG_TRACE_IRQFLAGS		#ifdef CONFIG_TRACE_IRQFLAGS
	call4 trace_hardirqs_off		abi_call trace_hardirqs_off
	#endif		#endif

	/* Jump if we are returning from kernel exceptions. */		/* Jump if we are returning from kernel exceptions. */

	l32i a3, a1, PT_PS		l32i abi_saved1, a1, PT_PS
	GET_THREAD_INFO(a2, a1)		GET_THREAD_INFO(a2, a1)
	l32i a4, a2, TI_FLAGS		l32i a4, a2, TI_FLAGS
	_bbci.l a3, PS_UM_BIT, 6f		_bbci.l abi_saved1, PS_UM_BIT, 6f

	/* Specific to a user exception exit:		/* Specific to a user exception exit:
	* We need to check some flags for signal handling and rescheduling,		* We need to check some flags for signal handling and rescheduling,
	@@ -509,20 +522,20 @@ common_exception_return:
	/* Call do_signal() */		/* Call do_signal() */

	#ifdef CONFIG_TRACE_IRQFLAGS		#ifdef CONFIG_TRACE_IRQFLAGS
	call4 trace_hardirqs_on		abi_call trace_hardirqs_on
	#endif		#endif
	rsil a2, 0		rsil a2, 0
	mov a6, a1		mov abi_arg0, a1
	call4 do_notify_resume # int do_notify_resume(struct pt_regs*)		abi_call do_notify_resume # int do_notify_resume(struct pt_regs*)
	j 1b		j 1b

	3: /* Reschedule */		3: /* Reschedule */

	#ifdef CONFIG_TRACE_IRQFLAGS		#ifdef CONFIG_TRACE_IRQFLAGS
	call4 trace_hardirqs_on		abi_call trace_hardirqs_on
	#endif		#endif
	rsil a2, 0		rsil a2, 0
	call4 schedule # void schedule (void)		abi_call schedule # void schedule (void)
	j 1b		j 1b

	#ifdef CONFIG_PREEMPTION		#ifdef CONFIG_PREEMPTION
	@@ -533,33 +546,33 @@ common_exception_return:

	l32i a4, a2, TI_PRE_COUNT		l32i a4, a2, TI_PRE_COUNT
	bnez a4, 4f		bnez a4, 4f
	call4 preempt_schedule_irq		abi_call preempt_schedule_irq
	j 4f		j 4f
	#endif		#endif

	#if XTENSA_FAKE_NMI		#if XTENSA_FAKE_NMI
	.LNMIexit:		.LNMIexit:
	l32i a3, a1, PT_PS		l32i abi_saved1, a1, PT_PS
	_bbci.l a3, PS_UM_BIT, 4f		_bbci.l abi_saved1, PS_UM_BIT, 4f
	#endif		#endif

	5:		5:
	#ifdef CONFIG_HAVE_HW_BREAKPOINT		#ifdef CONFIG_HAVE_HW_BREAKPOINT
	_bbci.l a4, TIF_DB_DISABLED, 7f		_bbci.l a4, TIF_DB_DISABLED, 7f
	call4 restore_dbreak		abi_call restore_dbreak
	7:		7:
	#endif		#endif
	#ifdef CONFIG_DEBUG_TLB_SANITY		#ifdef CONFIG_DEBUG_TLB_SANITY
	l32i a4, a1, PT_DEPC		l32i a4, a1, PT_DEPC
	bgeui a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 4f		bgeui a4, VALID_DOUBLE_EXCEPTION_ADDRESS, 4f
	call4 check_tlb_sanity		abi_call check_tlb_sanity
	#endif		#endif
	6:		6:
	4:		4:
	#ifdef CONFIG_TRACE_IRQFLAGS		#ifdef CONFIG_TRACE_IRQFLAGS
	extui a4, a3, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH		extui a4, abi_saved1, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH
	bgei a4, LOCKLEVEL, 1f		bgei a4, LOCKLEVEL, 1f
	call4 trace_hardirqs_on		abi_call trace_hardirqs_on
	1:		1:
	#endif		#endif
	/* Restore optional registers. */		/* Restore optional registers. */
	@@ -572,14 +585,15 @@ common_exception_return:
	l32i a2, a1, PT_SCOMPARE1		l32i a2, a1, PT_SCOMPARE1
	wsr a2, scompare1		wsr a2, scompare1
	#endif		#endif
	wsr a3, ps /* disable interrupts */		wsr abi_saved1, ps /* disable interrupts */

	_bbci.l a3, PS_UM_BIT, kernel_exception_exit		_bbci.l abi_saved1, PS_UM_BIT, kernel_exception_exit

	user_exception_exit:		user_exception_exit:

	/* Restore the state of the task and return from the exception. */		/* Restore the state of the task and return from the exception. */

			#if defined(USER_SUPPORT_WINDOWED)
	/* Switch to the user thread WINDOWBASE. Save SP temporarily in DEPC */		/* Switch to the user thread WINDOWBASE. Save SP temporarily in DEPC */

	l32i a2, a1, PT_WINDOWBASE		l32i a2, a1, PT_WINDOWBASE
	@@ -634,8 +648,10 @@ user_exception_exit:
	* frame where we had loaded a2), or at least the lower 4 bits		* frame where we had loaded a2), or at least the lower 4 bits
	* (if we have restored WSBITS-1 frames).		* (if we have restored WSBITS-1 frames).
	*/		*/

	2:		2:
			#else
			movi a2, 1
			#endif
	#if XCHAL_HAVE_THREADPTR		#if XCHAL_HAVE_THREADPTR
	l32i a3, a1, PT_THREADPTR		l32i a3, a1, PT_THREADPTR
	wur a3, threadptr		wur a3, threadptr
	@@ -650,6 +666,7 @@ user_exception_exit:

	kernel_exception_exit:		kernel_exception_exit:

			#if defined(__XTENSA_WINDOWED_ABI__)
	/* Check if we have to do a movsp.		/* Check if we have to do a movsp.
	*		*
	* We only have to do a movsp if the previous window-frame has		* We only have to do a movsp if the previous window-frame has
	@@ -702,6 +719,9 @@ kernel_exception_exit:
	*		*
	* Note: We expect a2 to hold PT_WMASK		* Note: We expect a2 to hold PT_WMASK
	*/		*/
			#else
			movi a2, 1
			#endif

	common_exception_exit:		common_exception_exit:

	@@ -927,7 +947,7 @@ ENTRY(unrecoverable_exception)
	wsr a1, windowbase		wsr a1, windowbase
	rsync		rsync

	movi a1, PS_WOE_MASK \| LOCKLEVEL		movi a1, KERNEL_PS_WOE_MASK \| LOCKLEVEL
	wsr a1, ps		wsr a1, ps
	rsync		rsync

	@@ -935,8 +955,8 @@ ENTRY(unrecoverable_exception)
	movi a0, 0		movi a0, 0
	addi a1, a1, PT_REGS_OFFSET		addi a1, a1, PT_REGS_OFFSET

	movi a6, unrecoverable_text		movi abi_arg0, unrecoverable_text
	call4 panic		abi_call panic

	1: j 1b		1: j 1b

	@@ -1403,12 +1423,12 @@ ENTRY(fast_syscall_spill_registers)
	rsr a3, excsave1		rsr a3, excsave1
	l32i a1, a3, EXC_TABLE_KSTK		l32i a1, a3, EXC_TABLE_KSTK

	movi a4, PS_WOE_MASK \| LOCKLEVEL		movi a4, KERNEL_PS_WOE_MASK \| LOCKLEVEL
	wsr a4, ps		wsr a4, ps
	rsync		rsync

	movi a6, SIGSEGV		movi abi_arg0, SIGSEGV
	call4 do_exit		abi_call do_exit

	/* shouldn't return, so panic */		/* shouldn't return, so panic */

	@@ -1887,57 +1907,77 @@ ENDPROC(fast_store_prohibited)

	ENTRY(system_call)		ENTRY(system_call)

			#if defined(__XTENSA_WINDOWED_ABI__)
	abi_entry_default		abi_entry_default
			#elif defined(__XTENSA_CALL0_ABI__)
			abi_entry(12)

			s32i a0, sp, 0
			s32i abi_saved0, sp, 4
			s32i abi_saved1, sp, 8
			mov abi_saved0, a2
			#else
			#error Unsupported Xtensa ABI
			#endif

	/* regs->syscall = regs->areg[2] */		/* regs->syscall = regs->areg[2] */

	l32i a7, a2, PT_AREG2		l32i a7, abi_saved0, PT_AREG2
	s32i a7, a2, PT_SYSCALL		s32i a7, abi_saved0, PT_SYSCALL

	GET_THREAD_INFO(a4, a1)		GET_THREAD_INFO(a4, a1)
	l32i a3, a4, TI_FLAGS		l32i abi_saved1, a4, TI_FLAGS
	movi a4, _TIF_WORK_MASK		movi a4, _TIF_WORK_MASK
	and a3, a3, a4		and abi_saved1, abi_saved1, a4
	beqz a3, 1f		beqz abi_saved1, 1f

	mov a6, a2		mov abi_arg0, abi_saved0
	call4 do_syscall_trace_enter		abi_call do_syscall_trace_enter
	beqz a6, .Lsyscall_exit		beqz abi_rv, .Lsyscall_exit
	l32i a7, a2, PT_SYSCALL		l32i a7, abi_saved0, PT_SYSCALL

	1:		1:
	/* syscall = sys_call_table[syscall_nr] */		/* syscall = sys_call_table[syscall_nr] */

	movi a4, sys_call_table		movi a4, sys_call_table
	movi a5, __NR_syscalls		movi a5, __NR_syscalls
	movi a6, -ENOSYS		movi abi_rv, -ENOSYS
	bgeu a7, a5, 1f		bgeu a7, a5, 1f

	addx4 a4, a7, a4		addx4 a4, a7, a4
	l32i a4, a4, 0		l32i abi_tmp0, a4, 0

	/* Load args: arg0 - arg5 are passed via regs. */		/* Load args: arg0 - arg5 are passed via regs. */

	l32i a6, a2, PT_AREG6		l32i abi_arg0, abi_saved0, PT_AREG6
	l32i a7, a2, PT_AREG3		l32i abi_arg1, abi_saved0, PT_AREG3
	l32i a8, a2, PT_AREG4		l32i abi_arg2, abi_saved0, PT_AREG4
	l32i a9, a2, PT_AREG5		l32i abi_arg3, abi_saved0, PT_AREG5
	l32i a10, a2, PT_AREG8		l32i abi_arg4, abi_saved0, PT_AREG8
	l32i a11, a2, PT_AREG9		l32i abi_arg5, abi_saved0, PT_AREG9

	callx4 a4		abi_callx abi_tmp0

	1: /* regs->areg[2] = return_value */		1: /* regs->areg[2] = return_value */

	s32i a6, a2, PT_AREG2		s32i abi_rv, abi_saved0, PT_AREG2
	bnez a3, 1f		bnez abi_saved1, 1f
	.Lsyscall_exit:		.Lsyscall_exit:
			#if defined(__XTENSA_WINDOWED_ABI__)
	abi_ret_default		abi_ret_default
			#elif defined(__XTENSA_CALL0_ABI__)
			l32i a0, sp, 0
			l32i abi_saved0, sp, 4
			l32i abi_saved1, sp, 8
			abi_ret(12)
			#else
			#error Unsupported Xtensa ABI
			#endif

	1:		1:
	mov a6, a2		mov abi_arg0, abi_saved0
	call4 do_syscall_trace_leave		abi_call do_syscall_trace_leave
	abi_ret_default		j .Lsyscall_exit

	ENDPROC(system_call)		ENDPROC(system_call)

	@@ -1988,8 +2028,18 @@ ENDPROC(system_call)

	ENTRY(_switch_to)		ENTRY(_switch_to)

			#if defined(__XTENSA_WINDOWED_ABI__)
	abi_entry(XTENSA_SPILL_STACK_RESERVE)		abi_entry(XTENSA_SPILL_STACK_RESERVE)
			#elif defined(__XTENSA_CALL0_ABI__)
			abi_entry(16)

			s32i a12, sp, 0
			s32i a13, sp, 4
			s32i a14, sp, 8
			s32i a15, sp, 12
			#else
			#error Unsupported Xtensa ABI
			#endif
	mov a11, a3 # and 'next' (a3)		mov a11, a3 # and 'next' (a3)

	l32i a4, a2, TASK_THREAD_INFO		l32i a4, a2, TASK_THREAD_INFO
	@@ -2033,7 +2083,9 @@ ENTRY(_switch_to)

	/* Flush register file. */		/* Flush register file. */

			#if defined(__XTENSA_WINDOWED_ABI__)
	spill_registers_kernel		spill_registers_kernel
			#endif

	/* Set kernel stack (and leave critical section)		/* Set kernel stack (and leave critical section)
	* Note: It's save to set it here. The stack will not be overwritten		* Note: It's save to set it here. The stack will not be overwritten
	@@ -2055,34 +2107,43 @@ ENTRY(_switch_to)
	wsr a14, ps		wsr a14, ps
	rsync		rsync

			#if defined(__XTENSA_WINDOWED_ABI__)
	abi_ret(XTENSA_SPILL_STACK_RESERVE)		abi_ret(XTENSA_SPILL_STACK_RESERVE)
			#elif defined(__XTENSA_CALL0_ABI__)
			l32i a12, sp, 0
			l32i a13, sp, 4
			l32i a14, sp, 8
			l32i a15, sp, 12
			abi_ret(16)
			#else
			#error Unsupported Xtensa ABI
			#endif

	ENDPROC(_switch_to)		ENDPROC(_switch_to)

	ENTRY(ret_from_fork)		ENTRY(ret_from_fork)

	/* void schedule_tail (struct task_struct *prev)		/* void schedule_tail (struct task_struct *prev)
	* Note: prev is still in a6 (return value from fake call4 frame)		* Note: prev is still in abi_arg0 (return value from fake call frame)
	*/		*/
	call4 schedule_tail		abi_call schedule_tail

	mov a6, a1
	call4 do_syscall_trace_leave

			mov abi_arg0, a1
			abi_call do_syscall_trace_leave
	j common_exception_return		j common_exception_return

	ENDPROC(ret_from_fork)		ENDPROC(ret_from_fork)

	/*		/*
	* Kernel thread creation helper		* Kernel thread creation helper
	* On entry, set up by copy_thread: a2 = thread_fn, a3 = thread_fn arg		* On entry, set up by copy_thread: abi_saved0 = thread_fn,
	* left from _switch_to: a6 = prev		* abi_saved1 = thread_fn arg. Left from _switch_to: abi_arg0 = prev
	*/		*/
	ENTRY(ret_from_kernel_thread)		ENTRY(ret_from_kernel_thread)

	call4 schedule_tail		abi_call schedule_tail
	mov a6, a3		mov abi_arg0, abi_saved1
	callx4 a2		abi_callx abi_saved0
	j common_exception_return		j common_exception_return

	ENDPROC(ret_from_kernel_thread)		ENDPROC(ret_from_kernel_thread)

arch/xtensa/kernel/head.S

+12 −10

Original line number	Original line	Diff line number	Diff line
	@@ -15,6 +15,7 @@
	* Kevin Chea		* Kevin Chea
	*/		*/

			#include <asm/asmmacro.h>
	#include <asm/processor.h>		#include <asm/processor.h>
	#include <asm/page.h>		#include <asm/page.h>
	#include <asm/cacheasm.h>		#include <asm/cacheasm.h>
	@@ -193,9 +194,10 @@ ENTRY(_startup)
	movi a1, start_info		movi a1, start_info
	l32i a1, a1, 0		l32i a1, a1, 0

	movi a2, PS_WOE_MASK \| LOCKLEVEL		/* Disable interrupts. */
	# WOE=1, INTLEVEL=LOCKLEVEL, UM=0		/* Enable window exceptions if kernel is built with windowed ABI. */
	wsr a2, ps # (enable reg-windows; progmode stack)		movi a2, KERNEL_PS_WOE_MASK \| LOCKLEVEL
			wsr a2, ps
	rsync		rsync

	#ifdef CONFIG_SMP		#ifdef CONFIG_SMP
	@@ -267,13 +269,13 @@ ENTRY(_startup)
	l32i a1, a1, 0		l32i a1, a1, 0
	#endif		#endif

	movi a6, 0		movi abi_arg0, 0
	xsr a6, excsave1		xsr abi_arg0, excsave1

	/* init_arch kick-starts the linux kernel */		/* init_arch kick-starts the linux kernel */

	call4 init_arch		abi_call init_arch
	call4 start_kernel		abi_call start_kernel

	should_never_return:		should_never_return:
	j should_never_return		j should_never_return
	@@ -297,10 +299,10 @@ should_never_return:
	s32i a3, a2, 0		s32i a3, a2, 0
	memw		memw

	movi a6, 0		movi abi_arg0, 0
	wsr a6, excsave1		wsr abi_arg0, excsave1

	call4 secondary_start_kernel		abi_call secondary_start_kernel
	j should_never_return		j should_never_return

	#endif /* CONFIG_SMP */		#endif /* CONFIG_SMP */

arch/xtensa/kernel/mcount.S

+36 −2

Original line number	Original line	Diff line number	Diff line
	@@ -17,11 +17,16 @@
	/*		/*
	* Entry condition:		* Entry condition:
	*		*
	* a2: a0 of the caller		* a2: a0 of the caller in windowed ABI
			* a10: a0 of the caller in call0 ABI
			*
			* In call0 ABI the function _mcount is called with the special ABI:
			* its argument is in a10 and all the usual argument registers (a2 - a7)
			* must be preserved in addition to callee-saved a12 - a15.
	*/		*/

	ENTRY(_mcount)		ENTRY(_mcount)
			#if defined(__XTENSA_WINDOWED_ABI__)
	abi_entry_default		abi_entry_default

	movi a4, ftrace_trace_function		movi a4, ftrace_trace_function
	@@ -42,7 +47,36 @@ ENTRY(_mcount)
	callx4 a4		callx4 a4

	abi_ret_default		abi_ret_default
			#elif defined(__XTENSA_CALL0_ABI__)
			abi_entry_default

			movi a9, ftrace_trace_function
			l32i a9, a9, 0
			movi a11, ftrace_stub
			bne a9, a11, 1f
			abi_ret_default

			1: abi_entry(28)
			s32i a0, sp, 0
			s32i a2, sp, 4
			s32i a3, sp, 8
			s32i a4, sp, 12
			s32i a5, sp, 16
			s32i a6, sp, 20
			s32i a7, sp, 24
			addi a2, a10, -MCOUNT_INSN_SIZE
			callx0 a9
			l32i a0, sp, 0
			l32i a2, sp, 4
			l32i a3, sp, 8
			l32i a4, sp, 12
			l32i a5, sp, 16
			l32i a6, sp, 20
			l32i a7, sp, 24
			abi_ret(28)
			#else
			#error Unsupported Xtensa ABI
			#endif
	ENDPROC(_mcount)		ENDPROC(_mcount)

	ENTRY(ftrace_stub)		ENTRY(ftrace_stub)

arch/xtensa/kernel/process.c

+24 −3

Original line number	Original line	Diff line number	Diff line
	@@ -211,11 +211,18 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
	struct thread_info *ti;		struct thread_info *ti;
	#endif		#endif

			#if defined(__XTENSA_WINDOWED_ABI__)
	/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */		/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
	SPILL_SLOT(childregs, 1) = (unsigned long)childregs;		SPILL_SLOT(childregs, 1) = (unsigned long)childregs;
	SPILL_SLOT(childregs, 0) = 0;		SPILL_SLOT(childregs, 0) = 0;

	p->thread.sp = (unsigned long)childregs;		p->thread.sp = (unsigned long)childregs;
			#elif defined(__XTENSA_CALL0_ABI__)
			/* Reserve 16 bytes for the _switch_to stack frame. */
			p->thread.sp = (unsigned long)childregs - 16;
			#else
			#error Unsupported Xtensa ABI
			#endif

	if (!(p->flags & (PF_KTHREAD \| PF_IO_WORKER))) {		if (!(p->flags & (PF_KTHREAD \| PF_IO_WORKER))) {
	struct pt_regs *regs = current_pt_regs();		struct pt_regs *regs = current_pt_regs();
	@@ -272,11 +279,25 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn,
	p->thread.ra = MAKE_RA_FOR_CALL(		p->thread.ra = MAKE_RA_FOR_CALL(
	(unsigned long)ret_from_kernel_thread, 1);		(unsigned long)ret_from_kernel_thread, 1);

	/* pass parameters to ret_from_kernel_thread:		/* pass parameters to ret_from_kernel_thread: */
	* a2 = thread_fn, a3 = thread_fn arg		#if defined(__XTENSA_WINDOWED_ABI__)
			/*
			* a2 = thread_fn, a3 = thread_fn arg.
			* Window underflow will load registers from the
			* spill slots on the stack on return from _switch_to.
	*/		*/
	SPILL_SLOT(childregs, 3) = thread_fn_arg;
	SPILL_SLOT(childregs, 2) = usp_thread_fn;		SPILL_SLOT(childregs, 2) = usp_thread_fn;
			SPILL_SLOT(childregs, 3) = thread_fn_arg;
			#elif defined(__XTENSA_CALL0_ABI__)
			/*
			* a12 = thread_fn, a13 = thread_fn arg.
			* _switch_to epilogue will load registers from the stack.
			*/
			((unsigned long *)p->thread.sp)[0] = usp_thread_fn;
			((unsigned long *)p->thread.sp)[1] = thread_fn_arg;
			#else
			#error Unsupported Xtensa ABI
			#endif

	/* Childregs are only used when we're going to userspace		/* Childregs are only used when we're going to userspace
	* in which case start_thread will set them up.		* in which case start_thread will set them up.