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linux/arch/arc/kernel/ctx_sw_asm.S

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-04 10:11:33 +02:00
/* SPDX-License-Identifier: GPL-2.0-only */
ARC: Process-creation/scheduling/idle-loop Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-18 15:12:18 +05:30
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* Vineetg: Aug 2009
* -Moved core context switch macro out of entry.S into this file.
* -This is the more "natural" hand written assembler
*/
ARC: Fix build breakage for !CONFIG_ARC_DW2_UNWIND Fixes: ec7ac6afd07b (ARC: switch to generic ENTRY/END assembler annotations) Reported-by: Anton Kolesov <akolesov@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2014-06-24 19:33:39 +05:30
#include <linux/linkage.h>
ARC: Process-creation/scheduling/idle-loop Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-18 15:12:18 +05:30
#include <asm/entry.h> /* For the SAVE_* macros */
#include <asm/asm-offsets.h>
ARC: [SMP] Fix build failures for large NR_CPUS ST.as only takes S9 (255) for offset. This was going out of range when accessing a task_struct field with 4k NR_CPUS (due to 128b of coumaks itself in there). Workaround by using an intermediate register to do the address scaling. There is some duplication of fix for ctx_sw.c and ctx_sw_asm.S however given that C version will go away soon I'm not bothering to factor out the common code. Reported-by: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-11-01 10:46:40 +05:30
#define KSP_WORD_OFF ((TASK_THREAD + THREAD_KSP) / 4)
ARC: __switch_to: asm with dwarf ops (vs. inline asm) __switch_to() is final step of context switch, swapping kernel modes stack (and callee regs) of outgoing task with next task. It is also the starting point of stack unwinging of a sleeping task and captures SP, FP, BLINK and the corresponding dwarf info. Back when dinosaurs still roamed around, ARC gas didn't support CFI pseudo ops and gcc was responsible for generating dwarf info. Thus it had to be written in "C" with inline asm to do the hand crafting of stack. The function prologue (and crucial saving of blink etc) was still gcc generated but not visible in code. Likewise dwarf info was missing. Now with modern tools, we can make things more obvious by writing the code in asm and adding approproate dwarf cfi pseudo ops. This is mostly non functional change, except for slight chnages to asm - ARCompact doesn't support MOV_S fp, sp, so we use MOV Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2020-05-14 00:16:34 -07:00
; IN
; - r0: prev task (also current)
; - r1: next task
; OUT
; - r0: prev task (so r0 not touched)
ARC: Process-creation/scheduling/idle-loop Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-18 15:12:18 +05:30
.section .sched.text,"ax",@progbits
ARC: __switch_to: asm with dwarf ops (vs. inline asm) __switch_to() is final step of context switch, swapping kernel modes stack (and callee regs) of outgoing task with next task. It is also the starting point of stack unwinging of a sleeping task and captures SP, FP, BLINK and the corresponding dwarf info. Back when dinosaurs still roamed around, ARC gas didn't support CFI pseudo ops and gcc was responsible for generating dwarf info. Thus it had to be written in "C" with inline asm to do the hand crafting of stack. The function prologue (and crucial saving of blink etc) was still gcc generated but not visible in code. Likewise dwarf info was missing. Now with modern tools, we can make things more obvious by writing the code in asm and adding approproate dwarf cfi pseudo ops. This is mostly non functional change, except for slight chnages to asm - ARCompact doesn't support MOV_S fp, sp, so we use MOV Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2020-05-14 00:16:34 -07:00
ENTRY_CFI(__switch_to)
/* save kernel stack frame regs of @prev task */
push blink
CFI_DEF_CFA_OFFSET 4
CFI_OFFSET r31, -4
push fp
CFI_DEF_CFA_OFFSET 8
CFI_OFFSET r27, -8
mov fp, sp
CFI_DEF_CFA_REGISTER r27
/* kernel mode callee regs of @prev */
ARC: Process-creation/scheduling/idle-loop Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-18 15:12:18 +05:30
SAVE_CALLEE_SAVED_KERNEL
ARC: __switch_to: asm with dwarf ops (vs. inline asm) __switch_to() is final step of context switch, swapping kernel modes stack (and callee regs) of outgoing task with next task. It is also the starting point of stack unwinging of a sleeping task and captures SP, FP, BLINK and the corresponding dwarf info. Back when dinosaurs still roamed around, ARC gas didn't support CFI pseudo ops and gcc was responsible for generating dwarf info. Thus it had to be written in "C" with inline asm to do the hand crafting of stack. The function prologue (and crucial saving of blink etc) was still gcc generated but not visible in code. Likewise dwarf info was missing. Now with modern tools, we can make things more obvious by writing the code in asm and adding approproate dwarf cfi pseudo ops. This is mostly non functional change, except for slight chnages to asm - ARCompact doesn't support MOV_S fp, sp, so we use MOV Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2020-05-14 00:16:34 -07:00
/* save final SP to @prev->thread.ksp */
ARC: [SMP] Fix build failures for large NR_CPUS ST.as only takes S9 (255) for offset. This was going out of range when accessing a task_struct field with 4k NR_CPUS (due to 128b of coumaks itself in there). Workaround by using an intermediate register to do the address scaling. There is some duplication of fix for ctx_sw.c and ctx_sw_asm.S however given that C version will go away soon I'm not bothering to factor out the common code. Reported-by: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-11-01 10:46:40 +05:30
#if KSP_WORD_OFF <= 255
st.as sp, [r0, KSP_WORD_OFF]
#else
/* Workaround for NR_CPUS=4k as ST.as can only take s9 offset */
ARC: __switch_to: asm with dwarf ops (vs. inline asm) __switch_to() is final step of context switch, swapping kernel modes stack (and callee regs) of outgoing task with next task. It is also the starting point of stack unwinging of a sleeping task and captures SP, FP, BLINK and the corresponding dwarf info. Back when dinosaurs still roamed around, ARC gas didn't support CFI pseudo ops and gcc was responsible for generating dwarf info. Thus it had to be written in "C" with inline asm to do the hand crafting of stack. The function prologue (and crucial saving of blink etc) was still gcc generated but not visible in code. Likewise dwarf info was missing. Now with modern tools, we can make things more obvious by writing the code in asm and adding approproate dwarf cfi pseudo ops. This is mostly non functional change, except for slight chnages to asm - ARCompact doesn't support MOV_S fp, sp, so we use MOV Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2020-05-14 00:16:34 -07:00
add2 r10, r0, KSP_WORD_OFF
st sp, [r10]
ARC: [SMP] Fix build failures for large NR_CPUS ST.as only takes S9 (255) for offset. This was going out of range when accessing a task_struct field with 4k NR_CPUS (due to 128b of coumaks itself in there). Workaround by using an intermediate register to do the address scaling. There is some duplication of fix for ctx_sw.c and ctx_sw_asm.S however given that C version will go away soon I'm not bothering to factor out the common code. Reported-by: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-11-01 10:46:40 +05:30
#endif
ARC: __switch_to: asm with dwarf ops (vs. inline asm) __switch_to() is final step of context switch, swapping kernel modes stack (and callee regs) of outgoing task with next task. It is also the starting point of stack unwinging of a sleeping task and captures SP, FP, BLINK and the corresponding dwarf info. Back when dinosaurs still roamed around, ARC gas didn't support CFI pseudo ops and gcc was responsible for generating dwarf info. Thus it had to be written in "C" with inline asm to do the hand crafting of stack. The function prologue (and crucial saving of blink etc) was still gcc generated but not visible in code. Likewise dwarf info was missing. Now with modern tools, we can make things more obvious by writing the code in asm and adding approproate dwarf cfi pseudo ops. This is mostly non functional change, except for slight chnages to asm - ARCompact doesn't support MOV_S fp, sp, so we use MOV Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2020-05-14 00:16:34 -07:00
/* update @next in _current_task[] and GP register caching it */
SET_CURR_TASK_ON_CPU r1, r10
/* load SP from @next->thread.ksp */
ld.as sp, [r1, KSP_WORD_OFF]
/* restore callee regs, stack frame regs of @next */
ARC: Process-creation/scheduling/idle-loop Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-18 15:12:18 +05:30
RESTORE_CALLEE_SAVED_KERNEL
ARC: __switch_to: asm with dwarf ops (vs. inline asm) __switch_to() is final step of context switch, swapping kernel modes stack (and callee regs) of outgoing task with next task. It is also the starting point of stack unwinging of a sleeping task and captures SP, FP, BLINK and the corresponding dwarf info. Back when dinosaurs still roamed around, ARC gas didn't support CFI pseudo ops and gcc was responsible for generating dwarf info. Thus it had to be written in "C" with inline asm to do the hand crafting of stack. The function prologue (and crucial saving of blink etc) was still gcc generated but not visible in code. Likewise dwarf info was missing. Now with modern tools, we can make things more obvious by writing the code in asm and adding approproate dwarf cfi pseudo ops. This is mostly non functional change, except for slight chnages to asm - ARCompact doesn't support MOV_S fp, sp, so we use MOV Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2020-05-14 00:16:34 -07:00
pop fp
CFI_RESTORE r27
CFI_DEF_CFA r28, 4
pop blink
CFI_RESTORE r31
CFI_DEF_CFA_OFFSET 0
j [blink]
ARC: dw2 unwind: enable cfi pseudo ops in string lib This uses a new set of annoations viz. ENTRY_CFI/END_CFI to enabel cfi ops generation. Note that we didn't change the normal ENTRY/EXIT as we don't actually want unwind info in the trap/exception/interrutp handlers which use these, as unwinder then gets confused (it keeps recursing vs. stopping). Semantically these are leaf routines and unwinding should stop when it hits those routines. Before ------ 28.52% 1.19% 9929 hackbench libuClibc-1.0.17.so [.] __write_nocancel | ---__write_nocancel |--8.95%--EV_Trap | --8.25%--sys_write | |--3.93%--sock_write_iter ... |--2.62%--memset <==== [LEAF entry as no unwind info] ^^^^^^ After ----- 29.46% 1.24% 13622 hackbench libuClibc-1.0.17.so [.] __write_nocancel | ---__write_nocancel |--9.31%--EV_Trap | --8.62%--sys_write | |--4.17%--sock_write_iter ... |--6.19%--sys_write | --6.19%--sock_write_iter | unix_stream_sendmsg | |--1.62%--sock_alloc_send_pskb | |--0.89%--sock_def_readable | |--0.88%--_raw_spin_unlock_irqrestore | |--0.69%--memset | | ^^^^^^ <==== [now in proper callframe] | | | --0.52%--skb_copy_datagram_from_iter Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-09-19 16:42:25 -07:00
END_CFI(__switch_to)
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