diff options
Diffstat (limited to 'arch/arc/kernel/process.c')
| -rw-r--r-- | arch/arc/kernel/process.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c new file mode 100644 index 000000000..e095c557a --- /dev/null +++ b/arch/arc/kernel/process.c @@ -0,0 +1,212 @@ +/* + * 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/mm.h> +#include <linux/fs.h> +#include <linux/unistd.h> +#include <linux/ptrace.h> +#include <linux/slab.h> +#include <linux/syscalls.h> +#include <linux/elf.h> +#include <linux/tick.h> + +SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr) +{ + task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr; + return 0; +} + +/* + * We return the user space TLS data ptr as sys-call return code + * Ideally it should be copy to user. + * However we can cheat by the fact that some sys-calls do return + * absurdly high values + * Since the tls dat aptr is not going to be in range of 0xFFFF_xxxx + * it won't be considered a sys-call error + * and it will be loads better than copy-to-user, which is a definite + * D-TLB Miss + */ +SYSCALL_DEFINE0(arc_gettls) +{ + return task_thread_info(current)->thr_ptr; +} + +void arch_cpu_idle(void) +{ + /* sleep, but enable all interrupts before committing */ + __asm__("sleep 0x3"); +} + +asmlinkage void ret_from_fork(void); + +/* + * 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) + * ~ ~ + * | --to-- | (CALLEE Regs of user mode) + * | r13 | + * ------------------ + * | fp | + * | blink | @ret_from_fork + * ------------------ + * | | + * ~ ~ + * ~ ~ + * | | + * ------------------ + * | r12 | + * ~ ~ + * | --to-- | (scratch Regs of user mode) + * | r0 | + * ------------------ + * | SP | + * | orig_r0 | + * | event/ECR | + * | user_r25 | + * ------------------ <===== END of PAGE + */ +int copy_thread(unsigned long clone_flags, + unsigned long usp, unsigned long kthread_arg, + struct task_struct *p) +{ + 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 */ + struct callee_regs *parent_callee; /* paren't callee */ + struct pt_regs *regs = current_pt_regs(); + + /* Mark the specific anchors to begin with (see pic above) */ + c_regs = task_pt_regs(p); + childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ + c_callee = ((struct callee_regs *)childksp) - 1; + + /* + * __switch_to() uses thread.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 */ + + /* __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)) { + memset(c_regs, 0, sizeof(struct pt_regs)); + + c_callee->r13 = kthread_arg; + c_callee->r14 = usp; /* function */ + + return 0; + } + + /*--------- User Task Only --------------*/ + + /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ + childksp[0] = 0; /* for POP fp */ + childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ + + /* Copy parents pt regs on child's kernel mode stack */ + *c_regs = *regs; + + if (usp) + c_regs->sp = usp; + + c_regs->r0 = 0; /* fork returns 0 in child */ + + parent_callee = ((struct callee_regs *)regs) - 1; + *c_callee = *parent_callee; + + if (unlikely(clone_flags & CLONE_SETTLS)) { + /* + * 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; + } else { + /* Normal fork case: set parent's TLS ptr in child */ + task_thread_info(p)->thr_ptr = + task_thread_info(current)->thr_ptr; + } + + return 0; +} + +/* + * Do necessary setup to start up a new user task + */ +void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp) +{ + regs->sp = usp; + regs->ret = pc; + + /* + * [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 | + STATUS_E1_MASK | STATUS_E2_MASK; + + /* bogus seed values for debugging */ + regs->lp_start = 0x10; + regs->lp_end = 0x80; +} + +/* + * Some archs flush debug and FPU info here + */ +void flush_thread(void) +{ +} + +/* + * Free any architecture-specific thread data structures, etc. + */ +void exit_thread(void) +{ +} + +int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) +{ + return 0; +} + +int elf_check_arch(const struct elf32_hdr *x) +{ + unsigned int eflags; + + if (x->e_machine != EM_ARCOMPACT) + return 0; + + eflags = x->e_flags; + if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_CURRENT) { + pr_err("ABI mismatch - you need newer toolchain\n"); + force_sigsegv(SIGSEGV, current); + return 0; + } + + return 1; +} +EXPORT_SYMBOL(elf_check_arch); |