| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) |
| * |
| * 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> |
| #include <linux/ptrace.h> |
| #include <linux/slab.h> |
| #include <linux/syscalls.h> |
| #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; |
| 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; |
| } |
| |
| 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 defintion |
| * 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 succeded */ |
| 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) |
| { |
| /* Re-enable interrupts <= default irq priority before commiting 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 */ |
| } |
| |
| #else /* ARC700 */ |
| |
| void arch_cpu_idle(void) |
| { |
| /* sleep, but enable both set E1/E2 (levels of interrutps) before committing */ |
| __asm__ __volatile__("sleep 0x3 \n"); |
| } |
| |
| #endif |
| |
| 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 kernel 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, |
| unsigned long 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 */ |
| 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 = 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; |
| |
| #ifdef CONFIG_ARC_CURR_IN_REG |
| /* |
| * setup usermode thread pointer #2: |
| * however for this special use of r25 in kernel, __switch_to() sets |
| * r25 for kernel needs and only in the final return path is usermode |
| * r25 setup, from pt_regs->user_r25. So set that up as well |
| */ |
| c_regs->user_r25 = c_callee->r25; |
| #endif |
| |
| 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 | ISA_INIT_STATUS_BITS; |
| |
| fpu_init_task(regs); |
| |
| /* 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) |
| { |
| } |
| |
| int elf_check_arch(const struct elf32_hdr *x) |
| { |
| unsigned int eflags; |
| |
| 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) { |
| pr_err("ABI mismatch - you need newer toolchain\n"); |
| force_sigsegv(SIGSEGV); |
| return 0; |
| } |
| |
| return 1; |
| } |
| EXPORT_SYMBOL(elf_check_arch); |