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linux_dsm_epyc7002/arch/riscv/include/asm/switch_to.h

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286 Based on 1 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 as published by the free software foundation version 2 this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 97 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.025053186@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-29 21:18:00 +07:00
/* SPDX-License-Identifier: GPL-2.0-only */
RISC-V: Task implementation This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-07-11 08:04:30 +07:00
/*
* Copyright (C) 2012 Regents of the University of California
*/
#ifndef _ASM_RISCV_SWITCH_TO_H
#define _ASM_RISCV_SWITCH_TO_H
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/csr.h>
Allow to disable FPU support FPU codes have been separated from common part in previous patches. This patch add the CONFIG_FPU option and some stubs, so that a no-FPU configuration is allowed. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-09 09:18:33 +07:00
#ifdef CONFIG_FPU
RISC-V: Task implementation This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-07-11 08:04:30 +07:00
extern void __fstate_save(struct task_struct *save_to);
extern void __fstate_restore(struct task_struct *restore_from);
static inline void __fstate_clean(struct pt_regs *regs)
{
riscv: Make __fstate_clean() work correctly. Make the __fstate_clean() function correctly set the state of sstatus.FS in pt_regs to SR_FS_CLEAN. Fixes: 7db91e57a0acd ("RISC-V: Task implementation") Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Christoph Hellwig <hch@lst.de> [paul.walmsley@sifive.com: expanded "Fixes" commit ID] Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-08-14 15:23:53 +07:00
regs->sstatus = (regs->sstatus & ~SR_FS) | SR_FS_CLEAN;
RISC-V: Task implementation This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-07-11 08:04:30 +07:00
}
riscv: Correct the initialized flow of FP register The following two reasons cause FP registers are sometimes not initialized before starting the user program. 1. Currently, the FP context is initialized in flush_thread() function and we expect these initial values to be restored to FP register when doing FP context switch. However, the FP context switch only occurs in switch_to function. Hence, if this process does not be scheduled out and scheduled in before entering the user space, the FP registers have no chance to initialize. 2. In flush_thread(), the state of reg->sstatus.FS inherits from the parent. Hence, the state of reg->sstatus.FS may be dirty. If this process is scheduled out during flush_thread() and initializing the FP register, the fstate_save() in switch_to will corrupt the FP context which has been initialized until flush_thread(). To solve the 1st case, the initialization of the FP register will be completed in start_thread(). It makes sure all FP registers are initialized before starting the user program. For the 2nd case, the state of reg->sstatus.FS in start_thread will be set to SR_FS_OFF to prevent this process from corrupting FP context in doing context save. The FP state is set to SR_FS_INITIAL in start_trhead(). Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Fixes: 7db91e57a0acd ("RISC-V: Task implementation") Cc: stable@vger.kernel.org [paul.walmsley@sifive.com: fixed brace alignment issue reported by checkpatch] Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-08-14 15:23:52 +07:00
static inline void fstate_off(struct task_struct *task,
struct pt_regs *regs)
{
regs->sstatus = (regs->sstatus & ~SR_FS) | SR_FS_OFF;
}
RISC-V: Task implementation This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-07-11 08:04:30 +07:00
static inline void fstate_save(struct task_struct *task,
struct pt_regs *regs)
{
if ((regs->sstatus & SR_FS) == SR_FS_DIRTY) {
__fstate_save(task);
__fstate_clean(regs);
}
}
static inline void fstate_restore(struct task_struct *task,
struct pt_regs *regs)
{
if ((regs->sstatus & SR_FS) != SR_FS_OFF) {
__fstate_restore(task);
__fstate_clean(regs);
}
}
static inline void __switch_to_aux(struct task_struct *prev,
struct task_struct *next)
{
struct pt_regs *regs;
regs = task_pt_regs(prev);
if (unlikely(regs->sstatus & SR_SD))
fstate_save(prev, regs);
fstate_restore(next, task_pt_regs(next));
}
Auto-detect whether a FPU exists We expect that a kernel with CONFIG_FPU=y can still support no-FPU machines. To do so, the kernel should first examine the existence of a FPU, then do nothing if a FPU does exist; otherwise, it should disable/bypass all FPU-related functions. In this patch, a new global variable, has_fpu, is created and determined when parsing the hardware capability from device tree during booting. This variable is used in those FPU-related functions. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-09 09:18:34 +07:00
extern bool has_fpu;
Allow to disable FPU support FPU codes have been separated from common part in previous patches. This patch add the CONFIG_FPU option and some stubs, so that a no-FPU configuration is allowed. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-09 09:18:33 +07:00
#else
Auto-detect whether a FPU exists We expect that a kernel with CONFIG_FPU=y can still support no-FPU machines. To do so, the kernel should first examine the existence of a FPU, then do nothing if a FPU does exist; otherwise, it should disable/bypass all FPU-related functions. In this patch, a new global variable, has_fpu, is created and determined when parsing the hardware capability from device tree during booting. This variable is used in those FPU-related functions. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-09 09:18:34 +07:00
#define has_fpu false
Allow to disable FPU support FPU codes have been separated from common part in previous patches. This patch add the CONFIG_FPU option and some stubs, so that a no-FPU configuration is allowed. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-09 09:18:33 +07:00
#define fstate_save(task, regs) do { } while (0)
#define fstate_restore(task, regs) do { } while (0)
#define __switch_to_aux(__prev, __next) do { } while (0)
#endif
RISC-V: Task implementation This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-07-11 08:04:30 +07:00
extern struct task_struct *__switch_to(struct task_struct *,
struct task_struct *);
#define switch_to(prev, next, last) \
do { \
struct task_struct *__prev = (prev); \
struct task_struct *__next = (next); \
Auto-detect whether a FPU exists We expect that a kernel with CONFIG_FPU=y can still support no-FPU machines. To do so, the kernel should first examine the existence of a FPU, then do nothing if a FPU does exist; otherwise, it should disable/bypass all FPU-related functions. In this patch, a new global variable, has_fpu, is created and determined when parsing the hardware capability from device tree during booting. This variable is used in those FPU-related functions. Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <vincentc@andestech.com> Cc: Zong Li <zong@andestech.com> Cc: Nick Hu <nickhu@andestech.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-09 09:18:34 +07:00
if (has_fpu) \
__switch_to_aux(__prev, __next); \
RISC-V: Task implementation This patch contains the implementation of tasks on RISC-V, most of which is involved in task switching. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-07-11 08:04:30 +07:00
((last) = __switch_to(__prev, __next)); \
} while (0)
#endif /* _ASM_RISCV_SWITCH_TO_H */
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