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303 lines
7.4 KiB
303 lines
7.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) |
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* |
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* Amit Bhor, Kanika Nema: Codito Technologies 2004 |
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*/ |
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#include <linux/errno.h> |
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#include <linux/module.h> |
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#include <linux/sched.h> |
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#include <linux/sched/task.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/mm.h> |
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#include <linux/fs.h> |
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#include <linux/unistd.h> |
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#include <linux/ptrace.h> |
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#include <linux/slab.h> |
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#include <linux/syscalls.h> |
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#include <linux/elf.h> |
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#include <linux/tick.h> |
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#include <asm/fpu.h> |
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SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr) |
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{ |
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task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr; |
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return 0; |
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} |
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/* |
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* We return the user space TLS data ptr as sys-call return code |
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* Ideally it should be copy to user. |
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* However we can cheat by the fact that some sys-calls do return |
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* absurdly high values |
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* Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx |
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* it won't be considered a sys-call error |
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* and it will be loads better than copy-to-user, which is a definite |
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* D-TLB Miss |
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*/ |
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SYSCALL_DEFINE0(arc_gettls) |
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{ |
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return task_thread_info(current)->thr_ptr; |
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} |
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SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) |
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{ |
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struct pt_regs *regs = current_pt_regs(); |
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u32 uval; |
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int ret; |
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/* |
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* This is only for old cores lacking LLOCK/SCOND, which by defintion |
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* can't possibly be SMP. Thus doesn't need to be SMP safe. |
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* And this also helps reduce the overhead for serializing in |
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* the UP case |
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*/ |
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WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP)); |
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/* Z indicates to userspace if operation succeded */ |
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regs->status32 &= ~STATUS_Z_MASK; |
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ret = access_ok(uaddr, sizeof(*uaddr)); |
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if (!ret) |
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goto fail; |
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again: |
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preempt_disable(); |
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ret = __get_user(uval, uaddr); |
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if (ret) |
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goto fault; |
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if (uval != expected) |
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goto out; |
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ret = __put_user(new, uaddr); |
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if (ret) |
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goto fault; |
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regs->status32 |= STATUS_Z_MASK; |
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out: |
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preempt_enable(); |
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return uval; |
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fault: |
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preempt_enable(); |
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if (unlikely(ret != -EFAULT)) |
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goto fail; |
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mmap_read_lock(current->mm); |
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ret = fixup_user_fault(current->mm, (unsigned long) uaddr, |
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FAULT_FLAG_WRITE, NULL); |
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mmap_read_unlock(current->mm); |
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if (likely(!ret)) |
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goto again; |
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fail: |
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force_sig(SIGSEGV); |
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return ret; |
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} |
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#ifdef CONFIG_ISA_ARCV2 |
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void arch_cpu_idle(void) |
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{ |
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/* Re-enable interrupts <= default irq priority before commiting SLEEP */ |
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const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO; |
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__asm__ __volatile__( |
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"sleep %0 \n" |
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: |
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:"I"(arg)); /* can't be "r" has to be embedded const */ |
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} |
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#else /* ARC700 */ |
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void arch_cpu_idle(void) |
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{ |
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/* sleep, but enable both set E1/E2 (levels of interrutps) before committing */ |
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__asm__ __volatile__("sleep 0x3 \n"); |
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} |
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#endif |
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asmlinkage void ret_from_fork(void); |
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/* |
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* Copy architecture-specific thread state |
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* |
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* Layout of Child kernel mode stack as setup at the end of this function is |
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* |
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* | ... | |
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* | ... | |
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* | unused | |
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* | | |
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* ------------------ |
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* | r25 | <==== top of Stack (thread.ksp) |
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* ~ ~ |
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* | --to-- | (CALLEE Regs of kernel mode) |
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* | r13 | |
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* ------------------ |
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* | fp | |
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* | blink | @ret_from_fork |
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* ------------------ |
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* | | |
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* ~ ~ |
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* ~ ~ |
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* | | |
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* ------------------ |
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* | r12 | |
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* ~ ~ |
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* | --to-- | (scratch Regs of user mode) |
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* | r0 | |
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* ------------------ |
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* | SP | |
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* | orig_r0 | |
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* | event/ECR | |
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* | user_r25 | |
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* ------------------ <===== END of PAGE |
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*/ |
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int copy_thread(unsigned long clone_flags, unsigned long usp, |
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unsigned long kthread_arg, struct task_struct *p, |
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unsigned long tls) |
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{ |
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struct pt_regs *c_regs; /* child's pt_regs */ |
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unsigned long *childksp; /* to unwind out of __switch_to() */ |
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struct callee_regs *c_callee; /* child's callee regs */ |
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struct callee_regs *parent_callee; /* paren't callee */ |
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struct pt_regs *regs = current_pt_regs(); |
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/* Mark the specific anchors to begin with (see pic above) */ |
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c_regs = task_pt_regs(p); |
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childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ |
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c_callee = ((struct callee_regs *)childksp) - 1; |
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/* |
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* __switch_to() uses thread.ksp to start unwinding stack |
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* For kernel threads we don't need to create callee regs, the |
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* stack layout nevertheless needs to remain the same. |
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* Also, since __switch_to anyways unwinds callee regs, we use |
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* this to populate kernel thread entry-pt/args into callee regs, |
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* so that ret_from_kernel_thread() becomes simpler. |
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*/ |
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p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ |
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/* __switch_to expects FP(0), BLINK(return addr) at top */ |
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childksp[0] = 0; /* fp */ |
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childksp[1] = (unsigned long)ret_from_fork; /* blink */ |
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if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { |
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memset(c_regs, 0, sizeof(struct pt_regs)); |
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c_callee->r13 = kthread_arg; |
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c_callee->r14 = usp; /* function */ |
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return 0; |
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} |
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/*--------- User Task Only --------------*/ |
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/* __switch_to expects FP(0), BLINK(return addr) at top of stack */ |
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childksp[0] = 0; /* for POP fp */ |
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childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ |
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/* Copy parents pt regs on child's kernel mode stack */ |
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*c_regs = *regs; |
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if (usp) |
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c_regs->sp = usp; |
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c_regs->r0 = 0; /* fork returns 0 in child */ |
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parent_callee = ((struct callee_regs *)regs) - 1; |
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*c_callee = *parent_callee; |
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if (unlikely(clone_flags & CLONE_SETTLS)) { |
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/* |
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* set task's userland tls data ptr from 4th arg |
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* clone C-lib call is difft from clone sys-call |
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*/ |
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task_thread_info(p)->thr_ptr = tls; |
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} else { |
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/* Normal fork case: set parent's TLS ptr in child */ |
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task_thread_info(p)->thr_ptr = |
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task_thread_info(current)->thr_ptr; |
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} |
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/* |
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* setup usermode thread pointer #1: |
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* when child is picked by scheduler, __switch_to() uses @c_callee to |
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* populate usermode callee regs: this works (despite being in a kernel |
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* function) since special return path for child @ret_from_fork() |
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* ensures those regs are not clobbered all the way to RTIE to usermode |
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*/ |
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c_callee->r25 = task_thread_info(p)->thr_ptr; |
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#ifdef CONFIG_ARC_CURR_IN_REG |
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/* |
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* setup usermode thread pointer #2: |
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* however for this special use of r25 in kernel, __switch_to() sets |
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* r25 for kernel needs and only in the final return path is usermode |
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* r25 setup, from pt_regs->user_r25. So set that up as well |
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*/ |
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c_regs->user_r25 = c_callee->r25; |
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#endif |
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return 0; |
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} |
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/* |
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* Do necessary setup to start up a new user task |
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*/ |
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void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp) |
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{ |
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regs->sp = usp; |
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regs->ret = pc; |
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/* |
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* [U]ser Mode bit set |
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* [L] ZOL loop inhibited to begin with - cleared by a LP insn |
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* Interrupts enabled |
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*/ |
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regs->status32 = STATUS_U_MASK | STATUS_L_MASK | ISA_INIT_STATUS_BITS; |
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fpu_init_task(regs); |
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/* bogus seed values for debugging */ |
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regs->lp_start = 0x10; |
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regs->lp_end = 0x80; |
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} |
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/* |
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* Some archs flush debug and FPU info here |
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*/ |
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void flush_thread(void) |
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{ |
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} |
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int elf_check_arch(const struct elf32_hdr *x) |
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{ |
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unsigned int eflags; |
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if (x->e_machine != EM_ARC_INUSE) { |
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pr_err("ELF not built for %s ISA\n", |
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is_isa_arcompact() ? "ARCompact":"ARCv2"); |
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return 0; |
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} |
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eflags = x->e_flags; |
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if ((eflags & EF_ARC_OSABI_MSK) != EF_ARC_OSABI_CURRENT) { |
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pr_err("ABI mismatch - you need newer toolchain\n"); |
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force_sigsegv(SIGSEGV); |
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return 0; |
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} |
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return 1; |
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} |
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EXPORT_SYMBOL(elf_check_arch);
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