From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- arch/hexagon/kernel/process.c | 213 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 arch/hexagon/kernel/process.c (limited to 'arch/hexagon/kernel/process.c') diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c new file mode 100644 index 000000000..656050c2e --- /dev/null +++ b/arch/hexagon/kernel/process.c @@ -0,0 +1,213 @@ +/* + * Process creation support for Hexagon + * + * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Program thread launch. Often defined as a macro in processor.h, + * but we're shooting for a small footprint and it's not an inner-loop + * performance-critical operation. + * + * The Hexagon ABI specifies that R28 is zero'ed before program launch, + * so that gets automatically done here. If we ever stop doing that here, + * we'll probably want to define the ELF_PLAT_INIT macro. + */ +void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) +{ + /* We want to zero all data-containing registers. Is this overkill? */ + memset(regs, 0, sizeof(*regs)); + /* We might want to also zero all Processor registers here */ + pt_set_usermode(regs); + pt_set_elr(regs, pc); + pt_set_rte_sp(regs, sp); +} + +/* + * Spin, or better still, do a hardware or VM wait instruction + * If hardware or VM offer wait termination even though interrupts + * are disabled. + */ +void arch_cpu_idle(void) +{ + __vmwait(); + /* interrupts wake us up, but irqs are still disabled */ + local_irq_enable(); +} + +/* + * Copy architecture-specific thread state + */ +int copy_thread(unsigned long clone_flags, unsigned long usp, + unsigned long arg, struct task_struct *p) +{ + struct thread_info *ti = task_thread_info(p); + struct hexagon_switch_stack *ss; + struct pt_regs *childregs; + asmlinkage void ret_from_fork(void); + + childregs = (struct pt_regs *) (((unsigned long) ti + THREAD_SIZE) - + sizeof(*childregs)); + + ti->regs = childregs; + + /* + * Establish kernel stack pointer and initial PC for new thread + * Note that unlike the usual situation, we do not copy the + * parent's callee-saved here; those are in pt_regs and whatever + * we leave here will be overridden on return to userland. + */ + ss = (struct hexagon_switch_stack *) ((unsigned long) childregs - + sizeof(*ss)); + ss->lr = (unsigned long)ret_from_fork; + p->thread.switch_sp = ss; + if (unlikely(p->flags & PF_KTHREAD)) { + memset(childregs, 0, sizeof(struct pt_regs)); + /* r24 <- fn, r25 <- arg */ + ss->r24 = usp; + ss->r25 = arg; + pt_set_kmode(childregs); + return 0; + } + memcpy(childregs, current_pt_regs(), sizeof(*childregs)); + ss->r2524 = 0; + + if (usp) + pt_set_rte_sp(childregs, usp); + + /* Child sees zero return value */ + childregs->r00 = 0; + + /* + * The clone syscall has the C signature: + * int [r0] clone(int flags [r0], + * void *child_frame [r1], + * void *parent_tid [r2], + * void *child_tid [r3], + * void *thread_control_block [r4]); + * ugp is used to provide TLS support. + */ + if (clone_flags & CLONE_SETTLS) + childregs->ugp = childregs->r04; + + /* + * Parent sees new pid -- not necessary, not even possible at + * this point in the fork process + * Might also want to set things like ti->addr_limit + */ + + return 0; +} + +/* + * Release any architecture-specific resources locked by thread + */ +void release_thread(struct task_struct *dead_task) +{ +} + +/* + * Some archs flush debug and FPU info here + */ +void flush_thread(void) +{ +} + +/* + * The "wait channel" terminology is archaic, but what we want + * is an identification of the point at which the scheduler + * was invoked by a blocked thread. + */ +unsigned long get_wchan(struct task_struct *p) +{ + unsigned long fp, pc; + unsigned long stack_page; + int count = 0; + if (!p || p == current || p->state == TASK_RUNNING) + return 0; + + stack_page = (unsigned long)task_stack_page(p); + fp = ((struct hexagon_switch_stack *)p->thread.switch_sp)->fp; + do { + if (fp < (stack_page + sizeof(struct thread_info)) || + fp >= (THREAD_SIZE - 8 + stack_page)) + return 0; + pc = ((unsigned long *)fp)[1]; + if (!in_sched_functions(pc)) + return pc; + fp = *(unsigned long *) fp; + } while (count++ < 16); + + return 0; +} + +/* + * Required placeholder. + */ +int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) +{ + return 0; +} + + +/* + * Called on the exit path of event entry; see vm_entry.S + * + * Interrupts will already be disabled. + * + * Returns 0 if there's no need to re-check for more work. + */ + +int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) +{ + if (!(thread_info_flags & _TIF_WORK_MASK)) { + return 0; + } /* shortcut -- no work to be done */ + + local_irq_enable(); + + if (thread_info_flags & _TIF_NEED_RESCHED) { + schedule(); + return 1; + } + + if (thread_info_flags & _TIF_SIGPENDING) { + do_signal(regs); + return 1; + } + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + return 1; + } + + /* Should not even reach here */ + panic("%s: bad thread_info flags 0x%08x\n", __func__, + thread_info_flags); +} -- cgit v1.2.3