17139053eb
The upstream kernel ABI (v3) is different from current out-of-tree (v2): * no-legacy-syscalls * user_regs_struct layout has changed So we rev up the ABI version Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
235 lines
6 KiB
C
235 lines
6 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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/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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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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static inline void arch_idle(void)
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{
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/* sleep, but enable all interrupts before committing */
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__asm__("sleep 0x3");
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}
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void cpu_idle(void)
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{
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/* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
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/* endless idle loop with no priority at all */
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while (1) {
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tick_nohz_idle_enter();
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rcu_idle_enter();
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doze:
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local_irq_disable();
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if (!need_resched()) {
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arch_idle();
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goto doze;
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} else {
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local_irq_enable();
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}
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rcu_idle_exit();
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tick_nohz_idle_exit();
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schedule_preempt_disabled();
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}
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}
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asmlinkage void ret_from_fork(void);
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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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* ------------------ <==== top of Stack (thread.ksp)
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* | UNUSED 1 word|
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* ------------------
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* | r25 |
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* ~ ~
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* | --to-- | (CALLEE Regs of user 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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* | UNUSED 1 word|
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* ------------------ <===== END of PAGE
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*/
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int copy_thread(unsigned long clone_flags,
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unsigned long usp, unsigned long arg,
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struct task_struct *p)
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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)) {
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memset(c_regs, 0, sizeof(struct pt_regs));
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c_callee->r13 = arg; /* argument to kernel thread */
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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 = regs->r3;
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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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return 0;
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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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/*
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* Free any architecture-specific thread data structures, etc.
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*/
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void exit_thread(void)
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{
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}
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
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{
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return 0;
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}
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/*
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* API: expected by schedular Code: If thread is sleeping where is that.
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* What is this good for? it will be always the scheduler or ret_from_fork.
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* So we hard code that anyways.
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*/
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unsigned long thread_saved_pc(struct task_struct *t)
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{
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struct pt_regs *regs = task_pt_regs(t);
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unsigned long blink = 0;
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/*
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* If the thread being queried for in not itself calling this, then it
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* implies it is not executing, which in turn implies it is sleeping,
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* which in turn implies it got switched OUT by the schedular.
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* In that case, it's kernel mode blink can reliably retrieved as per
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* the picture above (right above pt_regs).
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*/
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if (t != current && t->state != TASK_RUNNING)
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blink = *((unsigned int *)regs - 1);
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return blink;
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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_ARCOMPACT)
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return 0;
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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, current);
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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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