diff options
Diffstat (limited to 'arch/arc/kernel/process.c')
| -rw-r--r-- | arch/arc/kernel/process.c | 189 |
1 files changed, 137 insertions, 52 deletions
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index 07a3a968fe49..8166d0908713 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -1,16 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) * - * 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. - * * Amit Bhor, Kanika Nema: Codito Technologies 2004 */ #include <linux/errno.h> #include <linux/module.h> #include <linux/sched.h> +#include <linux/sched/task.h> +#include <linux/sched/task_stack.h> + #include <linux/mm.h> #include <linux/fs.h> #include <linux/unistd.h> @@ -20,6 +20,8 @@ #include <linux/elf.h> #include <linux/tick.h> +#include <asm/fpu.h> + SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr) { task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr; @@ -41,24 +43,107 @@ SYSCALL_DEFINE0(arc_gettls) return task_thread_info(current)->thr_ptr; } +SYSCALL_DEFINE3(arc_usr_cmpxchg, int __user *, uaddr, int, expected, int, new) +{ + struct pt_regs *regs = current_pt_regs(); + u32 uval; + int ret; + + /* + * This is only for old cores lacking LLOCK/SCOND, which by definition + * can't possibly be SMP. Thus doesn't need to be SMP safe. + * And this also helps reduce the overhead for serializing in + * the UP case + */ + WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP)); + + /* Z indicates to userspace if operation succeeded */ + regs->status32 &= ~STATUS_Z_MASK; + + ret = access_ok(uaddr, sizeof(*uaddr)); + if (!ret) + goto fail; + +again: + preempt_disable(); + + ret = __get_user(uval, uaddr); + if (ret) + goto fault; + + if (uval != expected) + goto out; + + ret = __put_user(new, uaddr); + if (ret) + goto fault; + + regs->status32 |= STATUS_Z_MASK; + +out: + preempt_enable(); + return uval; + +fault: + preempt_enable(); + + if (unlikely(ret != -EFAULT)) + goto fail; + + mmap_read_lock(current->mm); + ret = fixup_user_fault(current->mm, (unsigned long) uaddr, + FAULT_FLAG_WRITE, NULL); + mmap_read_unlock(current->mm); + + if (likely(!ret)) + goto again; + +fail: + force_sig(SIGSEGV); + return ret; +} + +#ifdef CONFIG_ISA_ARCV2 + void arch_cpu_idle(void) { - /* sleep, but enable all interrupts before committing */ - __asm__("sleep 0x3"); + /* Re-enable interrupts <= default irq priority before committing SLEEP */ + const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO; + + __asm__ __volatile__( + "sleep %0 \n" + : + :"I"(arg)); /* can't be "r" has to be embedded const */ + + raw_local_irq_disable(); } +#else /* ARC700 */ + +void arch_cpu_idle(void) +{ + /* sleep, but enable both set E1/E2 (levels of interrupts) before committing */ + __asm__ __volatile__("sleep 0x3 \n"); + raw_local_irq_disable(); +} + +#endif + asmlinkage void ret_from_fork(void); -/* Layout of Child kernel mode stack as setup at the end of this function is +/* + * Copy architecture-specific thread state + * + * Layout of Child kernel mode stack as setup at the end of this function is * * | ... | * | ... | * | unused | * | | * ------------------ - * | r25 | <==== top of Stack (thread.ksp) + * | r25 | <==== top of Stack (thread_info.ksp) * ~ ~ - * | --to-- | (CALLEE Regs of user mode) + * | --to-- | (CALLEE Regs of kernel mode) * | r13 | * ------------------ * | fp | @@ -77,13 +162,13 @@ asmlinkage void ret_from_fork(void); * | SP | * | orig_r0 | * | event/ECR | - * | user_r25 | * ------------------ <===== END of PAGE */ -int copy_thread(unsigned long clone_flags, - unsigned long usp, unsigned long arg, - struct task_struct *p) +int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) { + u64 clone_flags = args->flags; + unsigned long usp = args->stack; + unsigned long tls = args->tls; struct pt_regs *c_regs; /* child's pt_regs */ unsigned long *childksp; /* to unwind out of __switch_to() */ struct callee_regs *c_callee; /* child's callee regs */ @@ -96,24 +181,24 @@ int copy_thread(unsigned long clone_flags, c_callee = ((struct callee_regs *)childksp) - 1; /* - * __switch_to() uses thread.ksp to start unwinding stack + * __switch_to() uses thread_info.ksp to start unwinding stack * For kernel threads we don't need to create callee regs, the * stack layout nevertheless needs to remain the same. * Also, since __switch_to anyways unwinds callee regs, we use * this to populate kernel thread entry-pt/args into callee regs, * so that ret_from_kernel_thread() becomes simpler. */ - p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ + task_thread_info(p)->ksp = (unsigned long)c_callee; /* THREAD_INFO_KSP */ /* __switch_to expects FP(0), BLINK(return addr) at top */ childksp[0] = 0; /* fp */ childksp[1] = (unsigned long)ret_from_fork; /* blink */ - if (unlikely(p->flags & PF_KTHREAD)) { + if (unlikely(args->fn)) { memset(c_regs, 0, sizeof(struct pt_regs)); - c_callee->r13 = arg; /* argument to kernel thread */ - c_callee->r14 = usp; /* function */ + c_callee->r13 = (unsigned long)args->fn_arg; + c_callee->r14 = (unsigned long)args->fn; return 0; } @@ -140,69 +225,69 @@ int copy_thread(unsigned long clone_flags, * set task's userland tls data ptr from 4th arg * clone C-lib call is difft from clone sys-call */ - task_thread_info(p)->thr_ptr = regs->r3; + task_thread_info(p)->thr_ptr = tls; } else { /* Normal fork case: set parent's TLS ptr in child */ task_thread_info(p)->thr_ptr = task_thread_info(current)->thr_ptr; } + + /* + * setup usermode thread pointer #1: + * when child is picked by scheduler, __switch_to() uses @c_callee to + * populate usermode callee regs: this works (despite being in a kernel + * function) since special return path for child @ret_from_fork() + * ensures those regs are not clobbered all the way to RTIE to usermode + */ + c_callee->r25 = task_thread_info(p)->thr_ptr; + return 0; } /* - * Some archs flush debug and FPU info here + * Do necessary setup to start up a new user task */ -void flush_thread(void) +void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp) { -} + regs->sp = usp; + regs->ret = pc; -/* - * Free any architecture-specific thread data structures, etc. - */ -void exit_thread(void) -{ -} + /* + * [U]ser Mode bit set + * [L] ZOL loop inhibited to begin with - cleared by a LP insn + * Interrupts enabled + */ + regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS; -int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) -{ - return 0; + fpu_init_task(regs); + + /* bogus seed values for debugging */ + regs->lp_start = 0x10; + regs->lp_end = 0x80; } /* - * API: expected by schedular Code: If thread is sleeping where is that. - * What is this good for? it will be always the scheduler or ret_from_fork. - * So we hard code that anyways. + * Some archs flush debug and FPU info here */ -unsigned long thread_saved_pc(struct task_struct *t) +void flush_thread(void) { - struct pt_regs *regs = task_pt_regs(t); - unsigned long blink = 0; - - /* - * If the thread being queried for in not itself calling this, then it - * implies it is not executing, which in turn implies it is sleeping, - * which in turn implies it got switched OUT by the schedular. - * In that case, it's kernel mode blink can reliably retrieved as per - * the picture above (right above pt_regs). - */ - if (t != current && t->state != TASK_RUNNING) - blink = *((unsigned int *)regs - 1); - - return blink; } int elf_check_arch(const struct elf32_hdr *x) { unsigned int eflags; - if (x->e_machine != EM_ARCOMPACT) + if (x->e_machine != EM_ARC_INUSE) { + pr_err("ELF not built for %s ISA\n", + is_isa_arcompact() ? "ARCompact":"ARCv2"); return 0; + } eflags = x->e_flags; - if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_CURRENT) { + if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) { pr_err("ABI mismatch - you need newer toolchain\n"); - force_sigsegv(SIGSEGV, current); + force_fatal_sig(SIGSEGV); return 0; } |