xtensa/kernel/entry.S

113  *   a2:	new stack pointer, original value in depc
115  *   depc:	a2, original value saved on stack (PT_DEPC)
133 	/* Save a1, a2, a3, and set SP. */
136 	s32i	a1, a2, PT_AREG1
137 	s32i	a0, a2, PT_AREG2
138 	s32i	a3, a2, PT_AREG3
139 	mov	a1, a2
146 	movi	a2, 0
147 	wsr	a2, depc		# terminate user stack trace with 0
149 	xsr	a2, icountlevel
151 	s32i	a2, a1, PT_ICOUNTLEVEL
154 	rur	a2, threadptr
155 	s32i	a2, a1, PT_THREADPTR
159 	/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */
161 	rsr	a2, windowbase
163 	ssr	a2
164 	s32i	a2, a1, PT_WINDOWBASE
166 	slli	a2, a3, 32-WSBITS
167 	src	a2, a3, a2
168 	srli	a2, a2, 32-WSBITS
169 	s32i	a2, a1, PT_WMASK	# needed for restoring registers
173 	_bbsi.l	a2, 1, 1f
178 	_bbsi.l	a2, 2, 1f
183 	_bbsi.l	a2, 3, 1f
188 	_bnei	a2, 1, 1f		# only one valid frame?
197 	 * Assume a2 is:  001001000110001
202 1:	addi	a3, a2, -1		# eliminate '1' in bit 0: yyyyxxww0
204 	and	a3, a3, a2		# max. only one bit is set
216 	extui	a2, a2, 0, 4		# mask for the first 16 registers
217 	or	a2, a3, a2
218 	s32i	a2, a1, PT_WMASK	# needed when we restore the reg-file
225 	s32i	a2, a5, PT_AREG_END - 8
233 	rsr	a2, sar			# original WINDOWBASE
235 	ssl	a2
238 	wsr	a2, windowbase		# and WINDOWSTART
260  *   a2:	new stack pointer, original in DEPC
262  *   depc:	a2, original value saved on stack (PT_DEPC)
279 	/* Save a1, a2, a3, and set SP. */
281 	rsr	a0, depc		# get a2
282 	s32i	a1, a2, PT_AREG1
283 	s32i	a0, a2, PT_AREG2
284 	s32i	a3, a2, PT_AREG3
285 	mov	a1, a2
292 	movi	a2, 0
294 	xsr	a2, icountlevel
296 	s32i	a2, a1, PT_ICOUNTLEVEL
299 	/* Assume ws = xxwww1yyyy. Rotate ws right, so that a2 = yyyyxxwww1 */
301 	rsr	a2, windowbase		# don't need to save these, we only
303 	ssr	a2
304 	slli	a2, a3, 32-WSBITS
305 	src	a2, a3, a2
306 	srli	a2, a2, 32-WSBITS
307 	s32i	a2, a1, PT_WMASK	# needed for kernel_exception_exit
311 	_bbsi.l	a2, 1, 1f
316 	_bbsi.l	a2, 2, 1f
321 	_bbsi.l	a2, 3, 1f
327 	_bnei	a2, 1, 1f
343 	extui	a2, a1, TASK_SIZE_BITS,XX
345 	_bge	a2, a3, out_of_stack_panic
362 	rsr	a2, debugcause
364 	s32i	a2, a1, PT_DEBUGCAUSE
367 	movi	a2, NO_SYSCALL
369 	s32i	a2, a1, PT_SYSCALL
370 	movi	a2, 0
373 	xsr	a2, lcount
374 	s32i	a2, a1, PT_LCOUNT
384 	rsr	a2, exccause
387 	s32i	a2, a1, PT_EXCCAUSE
409 	beq	a2, a0, .Lmedium_level_irq
410 	bnei	a2, EXCCAUSE_LEVEL1_INTERRUPT, .Lexception
425 	addi	a2, a2, -EXCCAUSE_LEVEL1_INTERRUPT
429 	moveqz	a3, a0, a2		# a3 = LOCKLEVEL iff interrupt
430 	movi	a2, PS_WOE_MASK
431 	or	a3, a3, a2
432 	rsr	a2, exccause
465 	mov	a7, a2			# pass EXCCAUSE
466 	addx4	a4, a2, a4
478 	l32i	a2, a1, PT_EXCCAUSE
480 	beq	a2, a3, .LNMIexit
483 	irq_save a2, a3
491 	GET_THREAD_INFO(a2, a1)
492 	l32i	a4, a2, TI_FLAGS
514 	rsil	a2, 0
524 	rsil	a2, 0
534 	l32i	a4, a2, TI_PRE_COUNT
567 	load_xtregs_opt a1 a2 a4 a5 a6 a7 PT_XTREGS_OPT
572 	l32i    a2, a1, PT_SCOMPARE1
573 	wsr     a2, scompare1
585 	l32i	a2, a1, PT_WINDOWBASE
589 	ssr	a2			# preserve user's WB in the SAR
590 	wsr	a2, windowbase		# switch to user's saved WB
593 	l32i	a2, a1, PT_WMASK	# register frames saved (in bits 4...9)
604 	mov	a2, a6
609 	addi	a2, a6, -16		# decrementing Y in WMASK
614 	_bgeui	a2, 16, 2b
633 	 * Note: a2 still contains WMASK (if we've returned to the original
634 	 *	 frame where we had loaded a2), or at least the lower 4 bits
677 	l32i	a2, a1, PT_WMASK
678 	_beqi	a2, 1, common_exception_exit	# Spilled before exception,jump
703 	 * Note: We expect a2 to hold PT_WMASK
710 	_bbsi.l	a2, 1, 1f
715 	_bbsi.l	a2, 2, 1f
720 	_bbsi.l	a2, 3, 1f
728 1:	l32i	a2, a1, PT_PC
730 	wsr	a2, epc1
735 	l32i	a2, a1, PT_LBEG
737 	wsr	a2, lbeg
738 	l32i	a2, a1, PT_LCOUNT
740 	wsr	a2, lcount
745 	l32i	a2, a1, PT_ICOUNTLEVEL
747 	wsr	a2, icountlevel
754 	l32i	a2, a1, PT_AREG2
787 	wsr	a2, depc		# save a2 temporarily
788 	rsr	a2, SREG_EPC + XCHAL_DEBUGLEVEL
789 	wsr	a2, epc1
791 	movi	a2, EXCCAUSE_MAPPED_DEBUG
792 	wsr	a2, exccause
796 	movi	a2, 1 << PS_EXCM_BIT
797 	or	a2, a0, a2
798 	wsr	a2, ps
802 	bbsi.l	a2, PS_UM_BIT, 2f	# jump if user mode
804 	addi	a2, a1, -16-PT_SIZE	# assume kernel stack
807 	s32i	a1, a2, PT_AREG1
808 	s32i	a0, a2, PT_AREG0
810 	s32i	a0, a2, PT_DEPC		# mark it as a regular exception
813 	s32i	a3, a2, PT_AREG3
814 	s32i	a0, a2, PT_AREG2
815 	mov	a1, a2
823 	GET_THREAD_INFO(a2, a1)
824 	l32i	a3, a2, TI_PRE_COUNT
826 	s32i	a3, a2, TI_PRE_COUNT
829 	rsr	a2, ps
830 	bbsi.l	a2, PS_UM_BIT, _user_exception
833 2:	rsr	a2, excsave1
834 	l32i	a2, a2, EXC_TABLE_KSTK	# load kernel stack pointer
904  *   - a2 contains a valid stackpointer
981  *   a2:	new stack pointer, original in DEPC
983  *   depc:	a2, original value saved on stack (PT_DEPC)
993 	rsr	a2, ps
994 	extui	a3, a2, PS_OWB_SHIFT, PS_OWB_WIDTH
1001 	xor	a2, a2, a3
1002 	wsr	a2, ps
1026  *   a2:	new stack pointer, original in DEPC
1028  *   depc:	a2, original value saved on stack (PT_DEPC)
1036 	s32i	a3, a2, PT_AREG3
1040 	l32i	a3, a2, PT_AREG3
1041 	l32i	a0, a2, PT_AREG0
1042 	rsr	a2, depc
1063  *   a2:	new stack pointer, original in DEPC
1065  *   depc:	a2, original value saved on stack (PT_DEPC)
1077 	l32i	a0, a2, PT_DEPC
1092 	l32i    a0, a2, PT_AREG0        # restore a0
1093 	xsr     a2, depc                # restore a2, depc
1107  *        a2            a6                   a3    a4      a5
1111  *   a0:	a2 (syscall-nr), original value saved on stack (PT_AREG0)
1113  *   a2:	new stack pointer, original in a0 and DEPC
1116  *   depc:	a2, original value saved on stack (PT_DEPC)
1122  * Note: we don't have to save a2; a2 holds the return value
1131 	s32i	a7, a2, PT_AREG7	# we need an additional register
1133 	access_ok a3, a7, a0, a2, .Leac	# a0: scratch reg, a2: sp
1145 	l32i	a7, a2, PT_AREG7	# restore a7
1146 	l32i	a0, a2, PT_AREG0	# restore a0
1147 	movi	a2, 1			# and return 1
1150 1:	l32i	a7, a2, PT_AREG7	# restore a7
1151 	l32i	a0, a2, PT_AREG0	# restore a0
1152 	movi	a2, 0			# return 0 (note that we cannot set
1164 	mov	a0, a2
1165 	mov	a2, a7
1170 .Leac:	l32i	a7, a2, PT_AREG7	# restore a7
1171 	l32i	a0, a2, PT_AREG0	# restore a0
1172 	movi	a2, -EFAULT
1175 .Lill:	l32i	a7, a2, PT_AREG7	# restore a7
1176 	l32i	a0, a2, PT_AREG0	# restore a0
1177 	movi	a2, -EINVAL
1186 	l32i    a0, a2, PT_AREG0        # restore a0
1187 	movi	a2, -ENOSYS
1201  *   a2:	new stack pointer, original in DEPC
1203  *   depc:	a2, original value saved on stack (PT_DEPC)
1225 	s32i	a3, a2, PT_AREG3
1226 	s32i	a0, a2, PT_SAR
1230 	s32i	a4, a2, PT_AREG4
1231 	s32i	a7, a2, PT_AREG7
1232 	s32i	a8, a2, PT_AREG8
1233 	s32i	a11, a2, PT_AREG11
1234 	s32i	a12, a2, PT_AREG12
1235 	s32i	a15, a2, PT_AREG15
1370 	l32i	a3, a2, PT_SAR
1371 	l32i	a0, a2, PT_AREG0
1373 	l32i	a3, a2, PT_AREG3
1377 	l32i	a4, a2, PT_AREG4
1378 	l32i	a7, a2, PT_AREG7
1379 	l32i	a8, a2, PT_AREG8
1380 	l32i	a11, a2, PT_AREG11
1381 	l32i	a12, a2, PT_AREG12
1382 	l32i	a15, a2, PT_AREG15
1384 	movi	a2, 0
1436  * a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE
1442 	rsr	a2, windowbase	# get current windowbase (a2 is saved)
1444 	ssl	a2		# set shift (32 - WB)
1459 	slli	a2, a3, 32-WSBITS
1460 	src	a2, a3, a2	# a2 = xxwww1yyxxxwww1yy......
1461 	wsr	a2, windowstart	# set corrected windowstart
1464 	rsr	a2, excsave1
1465 	l32i	a2, a2, EXC_TABLE_DOUBLE_SAVE	# restore a2
1466 	xsr	a2, excsave1
1467 	s32i	a3, a2, EXC_TABLE_DOUBLE_SAVE	# save a3
1468 	l32i	a3, a2, EXC_TABLE_PARAM	# original WB (in user task)
1469 	xsr	a2, excsave1
1473 	 * a0, a1, a2	same
1485 	 *  a2: kernel stack pointer
1494 	addi	a2, a2, -PT_USER_SIZE
1495 	s32i	a0, a2, PT_AREG0
1500 	s32i	a3, a2, PT_DEPC		# setup depc
1515 	/* When we return here, all registers have been restored (a2: DEPC) */
1517 	wsr	a2, depc		# exception address
1521 	rsr	a2, excsave1
1522 	s32i	a3, a2, EXC_TABLE_DOUBLE_SAVE
1524 	s32i	a3, a2, EXC_TABLE_FIXUP
1526 	s32i	a3, a2, EXC_TABLE_PARAM
1527 	l32i	a2, a2, EXC_TABLE_KSTK
1547 	l32i    a0, a2, PT_AREG0        # restore a0
1548 	movi	a2, -ENOSYS
1579  *   a2:	new stack pointer, original in DEPC
1581  *   depc:	a2, original value saved on stack (PT_DEPC)
1592 	s32i	a1, a2, PT_AREG1
1593 	s32i	a3, a2, PT_AREG3
1611 	GET_CURRENT(a1,a2)
1672 	l32i	a0, a2, PT_AREG0
1673 	l32i	a1, a2, PT_AREG1
1674 	l32i	a3, a2, PT_AREG3
1675 	l32i	a2, a2, PT_DEPC
1677 	bgeui	a2, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f
1681 	rsr	a2, depc
1686 1:	xsr	a2, depc
1711 	l32i	a0, a2, PT_DEPC
1770 	s32i	a1, a2, PT_AREG2
1771 	mov	a1, a2
1773 	rsr	a2, ps
1774 	bbsi.l	a2, PS_UM_BIT, 1f
1789  *   a2:	new stack pointer, original in DEPC
1791  *   depc:	a2, original value saved on stack (PT_DEPC)
1802 	s32i	a1, a2, PT_AREG1
1803 	s32i	a3, a2, PT_AREG3
1805 	GET_CURRENT(a1,a2)
1845 	l32i	a3, a2, PT_AREG3
1846 	l32i	a1, a2, PT_AREG1
1847 	l32i	a0, a2, PT_AREG0
1848 	l32i	a2, a2, PT_DEPC
1850 	bgeui	a2, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f
1852 	rsr	a2, depc
1857 1:	xsr	a2, depc
1866 	rsr	a3, depc	# still holds a2
1867 	s32i	a3, a2, PT_AREG2
1868 	mov	a1, a2
1870 	rsr	a2, ps
1871 	bbsi.l	a2, PS_UM_BIT, 1f
1884  *                            a2                 a3
1894 	l32i	a7, a2, PT_AREG2
1895 	s32i	a7, a2, PT_SYSCALL
1903 	mov	a6, a2
1906 	l32i	a7, a2, PT_SYSCALL
1921 	l32i	a6, a2, PT_AREG6
1922 	l32i	a7, a2, PT_AREG3
1923 	l32i	a8, a2, PT_AREG4
1924 	l32i	a9, a2, PT_AREG5
1925 	l32i	a10, a2, PT_AREG8
1926 	l32i	a11, a2, PT_AREG9
1932 	s32i	a6, a2, PT_AREG2
1938 	mov	a6, a2
1986  *         a2                              a2                 a3
1995 	l32i	a4, a2, TASK_THREAD_INFO
2001 	addi	a10, a2, TASK_THREAD
2005 	s32i	a0, a2, THREAD_RA	# save return address
2006 	s32i	a1, a2, THREAD_SP	# save stack pointer
2078  * On entry, set up by copy_thread: a2 = thread_fn, a3 = thread_fn arg
2085 	callx4	a2