alpha/kernel/entry.S

1 /* SPDX-License-Identifier: GPL-2.0 */
5  * Kernel entry-points.
8 #include <asm/asm-offsets.h>
34 	.cfi_rel_offset	$18, 40
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.
79 	stq	$25, 120($sp)
85 	stq	$18, 176($sp)
96 	.cfi_rel_offset	$25, 120
125 	ldq	$25, 120($sp)
145 	.cfi_restore	$25
149 	.cfi_adjust_cfa_offset	-SP_OFF
174 	.cfi_adjust_cfa_offset	-SWITCH_STACK_SIZE
178  * Non-syscall kernel entry points.
195 	mov	$sp, $18
201 /* save $9 - $15 so the inline exception code can manipulate them.  */
239 	.cfi_adjust_cfa_offset	-56
254 	lda	$sp, -256($sp)
265 	bne	$0, entUnaUser	/* yup -> do user-level unaligned fault */
277 	/* 16-18 PAL-saved */
284 	stq	$25, 200($sp)
311 	.cfi_rel_offset	$25, 25*8
336 	/* 16-18 PAL-saved */
343 	ldq	$25, 200($sp)
370 	.cfi_restore	$25
375 	.cfi_adjust_cfa_offset	-256
384 	.cfi_adjust_cfa_offset	-256
386 	lda	$sp, -56($sp)
421 	.cfi_adjust_cfa_offset	-56
442  * Note that a0-a2 are not saved by PALcode as with the other entry points.
465 	stq	$18, SP_OFF+40($sp)
468 	.cfi_rel_offset	$18, SP_OFF+40
485 	cmovne	$26, 0, $18		/* $18 = 0 => non-restartable */
517 	ldq	$18, 0($sp)	/* old syscall nr (zero if success) */
518 	beq	$18, $ret_success
539  *      $18: The old syscall number, or zero if this is not a return
554 	 * restarts for us, so let $18 and $19 burn.
557 	mov	0, $18
582 	ldq	$18, SP_OFF+40($sp)
612 	ldq	$18, 0($sp)	/* old syscall nr (zero if success) */
613 	beq	$18, $strace_success
622 	mov	$18, $9		/* save old syscall number */
625 	mov	$9, $18
634  * Save and restore the switch stack -- aka the balance of the user context.
644 	lda	$sp, -SWITCH_STACK_SIZE($sp)
690 	.size	do_switch_stack, .-do_switch_stack
742 	.size	undo_switch_stack, .-undo_switch_stack
761 	.size	alpha_switch_to, .-alpha_switch_to
777  * ... and new kernel threads - here
823 	lda	$sp, -SWITCH_STACK_SIZE($sp)
845 	   Store a non-zero there - -ENOSYS we need in register
848 	lda	$0, -ENOSYS