a894e8ed09
Andy Chiu <andy.chiu@sifive.com> says:
This series provides support running Vector in kernel mode.
Additionally, kernel-mode Vector can be configured to run without
turnning off preemption on a CONFIG_PREEMPT kernel. Along with the
suport, we add Vector optimized copy_{to,from}_user. And provide a
simple threshold to decide when to run the vectorized functions.
We decided to drop vectorized memcpy/memset/memmove for the moment due
to the concern of memory side-effect in kernel_vector_begin(). The
detailed description can be found at v9[0]
This series is composed by 4 parts:
patch 1-4: adds basic support for kernel-mode Vector
patch 5: includes vectorized copy_{to,from}_user into the kernel
patch 6: refactor context switch code in fpu [1]
patch 7-10: provides some code refactors and support for preemptible
kernel-mode Vector.
This series can be merged if we feel any part of {1~4, 5, 6, 7~10} is
mature enough.
This patch is tested on a QEMU with V and verified that booting, normal
userspace operations all work as usual with thresholds set to 0. Also,
we test by launching multiple kernel threads which continuously executes
and verifies Vector operations in the background. The module that tests
these operation is expected to be upstream later.
* b4-shazam-merge:
riscv: vector: allow kernel-mode Vector with preemption
riscv: vector: use kmem_cache to manage vector context
riscv: vector: use a mask to write vstate_ctrl
riscv: vector: do not pass task_struct into riscv_v_vstate_{save,restore}()
riscv: fpu: drop SR_SD bit checking
riscv: lib: vectorize copy_to_user/copy_from_user
riscv: sched: defer restoring Vector context for user
riscv: Add vector extension XOR implementation
riscv: vector: make Vector always available for softirq context
riscv: Add support for kernel mode vector
Link: https://lore.kernel.org/r/20240115055929.4736-1-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com>
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* Copyright (C) 2012 Regents of the University of California
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* Copyright (C) 2017 SiFive
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*/
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#ifndef _ASM_RISCV_THREAD_INFO_H
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#define _ASM_RISCV_THREAD_INFO_H
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#include <asm/page.h>
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#include <linux/const.h>
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/* thread information allocation */
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#define THREAD_SIZE_ORDER CONFIG_THREAD_SIZE_ORDER
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#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
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/*
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* By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
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* checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
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* assembly.
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*/
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#ifdef CONFIG_VMAP_STACK
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#define THREAD_ALIGN (2 * THREAD_SIZE)
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#else
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#define THREAD_ALIGN THREAD_SIZE
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#endif
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#define THREAD_SHIFT (PAGE_SHIFT + THREAD_SIZE_ORDER)
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#define OVERFLOW_STACK_SIZE SZ_4K
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#define IRQ_STACK_SIZE THREAD_SIZE
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#ifndef __ASSEMBLY__
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#include <asm/processor.h>
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#include <asm/csr.h>
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/*
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* low level task data that entry.S needs immediate access to
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* - this struct should fit entirely inside of one cache line
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* - if the members of this struct changes, the assembly constants
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* in asm-offsets.c must be updated accordingly
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* - thread_info is included in task_struct at an offset of 0. This means that
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* tp points to both thread_info and task_struct.
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*/
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struct thread_info {
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unsigned long flags; /* low level flags */
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int preempt_count; /* 0=>preemptible, <0=>BUG */
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/*
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* These stack pointers are overwritten on every system call or
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* exception. SP is also saved to the stack it can be recovered when
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* overwritten.
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*/
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long kernel_sp; /* Kernel stack pointer */
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long user_sp; /* User stack pointer */
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int cpu;
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unsigned long syscall_work; /* SYSCALL_WORK_ flags */
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#ifdef CONFIG_SHADOW_CALL_STACK
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void *scs_base;
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void *scs_sp;
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#endif
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};
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#ifdef CONFIG_SHADOW_CALL_STACK
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#define INIT_SCS \
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.scs_base = init_shadow_call_stack, \
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.scs_sp = init_shadow_call_stack,
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#else
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#define INIT_SCS
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#endif
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/*
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* macros/functions for gaining access to the thread information structure
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*
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* preempt_count needs to be 1 initially, until the scheduler is functional.
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*/
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.flags = 0, \
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.preempt_count = INIT_PREEMPT_COUNT, \
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INIT_SCS \
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}
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void arch_release_task_struct(struct task_struct *tsk);
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int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
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#endif /* !__ASSEMBLY__ */
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/*
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* thread information flags
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* - these are process state flags that various assembly files may need to
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* access
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* - pending work-to-be-done flags are in lowest half-word
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* - other flags in upper half-word(s)
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*/
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#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
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#define TIF_SIGPENDING 2 /* signal pending */
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#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
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#define TIF_RESTORE_SIGMASK 4 /* restore signal mask in do_signal() */
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#define TIF_MEMDIE 5 /* is terminating due to OOM killer */
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#define TIF_NOTIFY_SIGNAL 9 /* signal notifications exist */
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#define TIF_UPROBE 10 /* uprobe breakpoint or singlestep */
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#define TIF_32BIT 11 /* compat-mode 32bit process */
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#define TIF_RISCV_V_DEFER_RESTORE 12 /* restore Vector before returing to user */
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#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
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#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
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#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
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#define _TIF_UPROBE (1 << TIF_UPROBE)
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#define _TIF_RISCV_V_DEFER_RESTORE (1 << TIF_RISCV_V_DEFER_RESTORE)
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#define _TIF_WORK_MASK \
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(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
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_TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
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#endif /* _ASM_RISCV_THREAD_INFO_H */
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