v4.19.13 snapshot.
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
new file mode 100644
index 0000000..8ce6e72
--- /dev/null
+++ b/arch/arc/kernel/process.c
@@ -0,0 +1,322 @@
+/*
+ * 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>
+#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;
+}
+
+SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, 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(VERIFY_WRITE, 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;
+
+ down_read(¤t->mm->mmap_sem);
+ ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr,
+ FAULT_FLAG_WRITE, NULL);
+ up_read(¤t->mm->mmap_sem);
+
+ if (likely(!ret))
+ goto again;
+
+fail:
+ force_sig(SIGSEGV, current);
+ 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 */
+}
+
+#elif defined(CONFIG_EZNPS_MTM_EXT) /* ARC700 variant in NPS */
+
+void arch_cpu_idle(void)
+{
+ /* only the calling HW thread needs to sleep */
+ __asm__ __volatile__(
+ ".word %0 \n"
+ :
+ :"i"(CTOP_INST_HWSCHD_WFT_IE12));
+}
+
+#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)
+{
+ 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;
+ }
+
+
+ /*
+ * 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;
+
+#ifdef CONFIG_EZNPS_MTM_EXT
+ regs->eflags = 0;
+#endif
+
+ /* 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 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_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, current);
+ return 0;
+ }
+
+ return 1;
+}
+EXPORT_SYMBOL(elf_check_arch);