alpha/kernel/entry.S

1 /* SPDX-License-Identifier: GPL-2.0 */
5  * Kernel entry-points.
8 #include <asm/asm-offsets.h>
39 	.size	\func, . - \func
43  * This defines the normal kernel pt-regs layout.
45  * regs 9-15 preserved by C code
46  * regs 16-18 saved by PAL-code
47  * regs 29-30 saved and set up by PAL-code
48  * JRP - Save regs 16-18 in a special area of the stack, so that
49  * the palcode-provided values are available to the signal handler.
55 	stq	$0, 0($sp)
61 	.cfi_rel_offset	$0, 0
72 	stq	$19, 72($sp)
90 	.cfi_rel_offset $19, 72
102 	lda	$19, alpha_mv
103 	ldq	$0, 0($sp)
108 	ldq	$20, HAE_CACHE($19)
116 	ldq	$20, HAE_REG($19)
117 	stq	$21, HAE_CACHE($19)
118 	stq	$21, 0($20)
119 99:	ldq	$19, 72($sp)
130 	.cfi_restore	$0
139 	.cfi_restore	$19
149 	.cfi_adjust_cfa_offset	-SP_OFF
155 	.cfi_rel_offset	$9, 0
173 	.cfi_adjust_cfa_offset	-SWITCH_STACK_SIZE
177  * Non-syscall kernel entry points.
182 	lda	$8, 0x3fff
185 	mov	$sp, $19
191 	lda	$8, 0x3fff
200 /* save $9 - $15 so the inline exception code can manipulate them.  */
203 	stq	$9, 0($sp)
210 	.cfi_rel_offset	$9, 0
217 	addq	$sp, 56, $19
219 	lda	$8, 0x3fff
223 	ldq	$9, 0($sp)
238 	.cfi_adjust_cfa_offset	-56
245 	lda	$8, 0x3fff
253 	lda	$sp, -256($sp)
255 	stq	$0, 0($sp)
256 	.cfi_rel_offset	$0, 0
258 	ldq	$0, 256($sp)	/* get PS */
262 	and	$0, 8, $0		/* user mode? */
264 	bne	$0, entUnaUser	/* yup -> do user-level unaligned fault */
276 	/* 16-18 PAL-saved */
277 	stq	$19, 152($sp)
287 	mov	$sp, $19
304 	.cfi_rel_offset	$19, 19*8
315 	lda	$8, 0x3fff
319 	ldq	$0, 0($sp)
335 	/* 16-18 PAL-saved */
336 	ldq	$19, 152($sp)
363 	.cfi_restore	$19
374 	.cfi_adjust_cfa_offset	-256
380 	ldq	$0, 0($sp)	/* restore original $0 */
382 	.cfi_restore	$0
383 	.cfi_adjust_cfa_offset	-256
385 	lda	$sp, -56($sp)
387 	stq	$9, 0($sp)
394 	.cfi_rel_offset	$9, 0
401 	lda	$8, 0x3fff
402 	addq	$sp, 56, $19
405 	ldq	$9, 0($sp)
420 	.cfi_adjust_cfa_offset	-56
426 	lda	$8, 0x3fff
441  * Note that a0-a2 are not saved by PALcode as with the other entry points.
454 	lda	$8, 0x3fff
460 	cmpult	$0, $4, $4
463 	s8addq	$0, $5, $5
476 	ldq	$27, 0($5)
478 	ldgp	$gp, 0($26)
479 	blt	$0, $syscall_error	/* the call failed */
481 	stq	$0, 0($sp)
482 	stq	$31, 72($sp)		/* a3=0 => no error */
487 	cmovne	$26, 0, $18		/* $18 = 0 => non-restartable */
488 	ldq	$0, SP_OFF($sp)
489 	and	$0, 8, $0
490 	beq	$0, ret_to_kernel
519 	 * Those functions must zero $0 (v0) directly in the stack
523 	ldq	$18, 0($sp)	/* old syscall nr (zero if success) */
526 	ldq	$19, 72($sp)	/* .. and this a3 */
527 	subq	$31, $0, $0	/* with error in v0 */
529 	stq	$0, 0($sp)
542  *      $19: The old a3 value
555 	 * restarts for us, so let $18 and $19 burn.
558 	mov	0, $18
592 	ldq	$19, 72($sp)
600 	cmpult	$0, $1, $1
601 	s8addq	$0, $2, $2
603 	ldq	$27, 0($2)
606 	ldgp	$gp, 0($26)
609 	blt	$0, $strace_error	/* the call failed */
611 	stq	$31, 72($sp)		/* a3=0 => no error */
612 	stq	$0, 0($sp)		/* save return value */
621 	ldq	$18, 0($sp)	/* old syscall nr (zero if success) */
623 	ldq	$19, 72($sp)	/* .. and this a3 */
625 	subq	$31, $0, $0	/* with error in v0 */
627 	stq	$0, 0($sp)
632 	mov	$19, $10	/* save old a3 */
635 	mov	$10, $19
643  * Save and restore the switch stack -- aka the balance of the user context.
650 	.cfi_def_cfa $sp, 0
653 	lda	$sp, -SWITCH_STACK_SIZE($sp)
655 	stq	$9, 0($sp)
665 	.size	do_switch_stack, .-do_switch_stack
670 	.cfi_def_cfa $sp, 0
673 	ldq	$9, 0($sp)
684 	.size	undo_switch_stack, .-undo_switch_stack
692 	V( 0); V( 1); V( 2); V( 3)
696 	V(16); V(17); V(18); V(19)
702 	ldt	$f0, FR(0)	# don't let "__save_fpu" change fp state.
705 	.size	__save_fpu, .-__save_fpu
714 	V( 0); V( 1); V( 2); V( 3)
719 	V(16); V(17); V(18); V(19)
747 	lda	$8, 0x3fff
750 	mov	$17, $0
753 	.size	alpha_switch_to, .-alpha_switch_to
769  * ... and new kernel threads - here
794 	.prologue 0
821 	.prologue 0
824 	lda	$sp, -SWITCH_STACK_SIZE($sp)
840 	.prologue 0
844 	   That works nicely, but for real syscall 0 we need to
846 	   Store a non-zero there - -ENOSYS we need in register
849 	lda	$0, -ENOSYS
851 	stq	$0, 0($sp)