Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 303 insertions, 0 deletions

diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
new file mode 100644
index 000000000..8cf2caae9
--- /dev/null
+++ b/arch/arc/kernel/process.c
@@ -0,0 +1,303 @@
+// 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 | PF_IO_WORKER))) {
+		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);