summaryrefslogtreecommitdiff
path: root/arch/xtensa/kernel/process.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/xtensa/kernel/process.c')
-rw-r--r--arch/xtensa/kernel/process.c336
1 files changed, 336 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c
new file mode 100644
index 00000000..6a2d6edf
--- /dev/null
+++ b/arch/xtensa/kernel/process.c
@@ -0,0 +1,336 @@
+/*
+ * arch/xtensa/kernel/process.c
+ *
+ * Xtensa Processor version.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2005 Tensilica Inc.
+ *
+ * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
+ * Chris Zankel <chris@zankel.net>
+ * Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
+ * Kevin Chea
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/elf.h>
+#include <linux/init.h>
+#include <linux/prctl.h>
+#include <linux/init_task.h>
+#include <linux/module.h>
+#include <linux/mqueue.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/platform.h>
+#include <asm/mmu.h>
+#include <asm/irq.h>
+#include <linux/atomic.h>
+#include <asm/asm-offsets.h>
+#include <asm/regs.h>
+
+extern void ret_from_fork(void);
+
+struct task_struct *current_set[NR_CPUS] = {&init_task, };
+
+void (*pm_power_off)(void) = NULL;
+EXPORT_SYMBOL(pm_power_off);
+
+
+#if XTENSA_HAVE_COPROCESSORS
+
+void coprocessor_release_all(struct thread_info *ti)
+{
+ unsigned long cpenable;
+ int i;
+
+ /* Make sure we don't switch tasks during this operation. */
+
+ preempt_disable();
+
+ /* Walk through all cp owners and release it for the requested one. */
+
+ cpenable = ti->cpenable;
+
+ for (i = 0; i < XCHAL_CP_MAX; i++) {
+ if (coprocessor_owner[i] == ti) {
+ coprocessor_owner[i] = 0;
+ cpenable &= ~(1 << i);
+ }
+ }
+
+ ti->cpenable = cpenable;
+ coprocessor_clear_cpenable();
+
+ preempt_enable();
+}
+
+void coprocessor_flush_all(struct thread_info *ti)
+{
+ unsigned long cpenable;
+ int i;
+
+ preempt_disable();
+
+ cpenable = ti->cpenable;
+
+ for (i = 0; i < XCHAL_CP_MAX; i++) {
+ if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti)
+ coprocessor_flush(ti, i);
+ cpenable >>= 1;
+ }
+
+ preempt_enable();
+}
+
+#endif
+
+
+/*
+ * Powermanagement idle function, if any is provided by the platform.
+ */
+
+void cpu_idle(void)
+{
+ local_irq_enable();
+
+ /* endless idle loop with no priority at all */
+ while (1) {
+ while (!need_resched())
+ platform_idle();
+ schedule_preempt_disabled();
+ }
+}
+
+/*
+ * This is called when the thread calls exit().
+ */
+void exit_thread(void)
+{
+#if XTENSA_HAVE_COPROCESSORS
+ coprocessor_release_all(current_thread_info());
+#endif
+}
+
+/*
+ * Flush thread state. This is called when a thread does an execve()
+ * Note that we flush coprocessor registers for the case execve fails.
+ */
+void flush_thread(void)
+{
+#if XTENSA_HAVE_COPROCESSORS
+ struct thread_info *ti = current_thread_info();
+ coprocessor_flush_all(ti);
+ coprocessor_release_all(ti);
+#endif
+}
+
+/*
+ * This is called before the thread is copied.
+ */
+void prepare_to_copy(struct task_struct *tsk)
+{
+#if XTENSA_HAVE_COPROCESSORS
+ coprocessor_flush_all(task_thread_info(tsk));
+#endif
+}
+
+/*
+ * Copy thread.
+ *
+ * The stack layout for the new thread looks like this:
+ *
+ * +------------------------+ <- sp in childregs (= tos)
+ * | childregs |
+ * +------------------------+ <- thread.sp = sp in dummy-frame
+ * | dummy-frame | (saved in dummy-frame spill-area)
+ * +------------------------+
+ *
+ * We create a dummy frame to return to ret_from_fork:
+ * a0 points to ret_from_fork (simulating a call4)
+ * sp points to itself (thread.sp)
+ * a2, a3 are unused.
+ *
+ * Note: This is a pristine frame, so we don't need any spill region on top of
+ * childregs.
+ */
+
+int copy_thread(unsigned long clone_flags, unsigned long usp,
+ unsigned long unused,
+ struct task_struct * p, struct pt_regs * regs)
+{
+ struct pt_regs *childregs;
+ struct thread_info *ti;
+ unsigned long tos;
+ int user_mode = user_mode(regs);
+
+ /* Set up new TSS. */
+ tos = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+ if (user_mode)
+ childregs = (struct pt_regs*)(tos - PT_USER_SIZE);
+ else
+ childregs = (struct pt_regs*)tos - 1;
+
+ *childregs = *regs;
+
+ /* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
+ *((int*)childregs - 3) = (unsigned long)childregs;
+ *((int*)childregs - 4) = 0;
+
+ childregs->areg[1] = tos;
+ childregs->areg[2] = 0;
+ p->set_child_tid = p->clear_child_tid = NULL;
+ p->thread.ra = MAKE_RA_FOR_CALL((unsigned long)ret_from_fork, 0x1);
+ p->thread.sp = (unsigned long)childregs;
+
+ if (user_mode(regs)) {
+
+ int len = childregs->wmask & ~0xf;
+ childregs->areg[1] = usp;
+ memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],
+ &regs->areg[XCHAL_NUM_AREGS - len/4], len);
+// FIXME: we need to set THREADPTR in thread_info...
+ if (clone_flags & CLONE_SETTLS)
+ childregs->areg[2] = childregs->areg[6];
+
+ } else {
+ /* In kernel space, we start a new thread with a new stack. */
+ childregs->wmask = 1;
+ }
+
+#if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS)
+ ti = task_thread_info(p);
+ ti->cpenable = 0;
+#endif
+
+ return 0;
+}
+
+
+/*
+ * These bracket the sleeping functions..
+ */
+
+unsigned long get_wchan(struct task_struct *p)
+{
+ unsigned long sp, pc;
+ unsigned long stack_page = (unsigned long) task_stack_page(p);
+ int count = 0;
+
+ if (!p || p == current || p->state == TASK_RUNNING)
+ return 0;
+
+ sp = p->thread.sp;
+ pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
+
+ do {
+ if (sp < stack_page + sizeof(struct task_struct) ||
+ sp >= (stack_page + THREAD_SIZE) ||
+ pc == 0)
+ return 0;
+ if (!in_sched_functions(pc))
+ return pc;
+
+ /* Stack layout: sp-4: ra, sp-3: sp' */
+
+ pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);
+ sp = *(unsigned long *)sp - 3;
+ } while (count++ < 16);
+ return 0;
+}
+
+/*
+ * xtensa_gregset_t and 'struct pt_regs' are vastly different formats
+ * of processor registers. Besides different ordering,
+ * xtensa_gregset_t contains non-live register information that
+ * 'struct pt_regs' does not. Exception handling (primarily) uses
+ * 'struct pt_regs'. Core files and ptrace use xtensa_gregset_t.
+ *
+ */
+
+void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs)
+{
+ unsigned long wb, ws, wm;
+ int live, last;
+
+ wb = regs->windowbase;
+ ws = regs->windowstart;
+ wm = regs->wmask;
+ ws = ((ws >> wb) | (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1);
+
+ /* Don't leak any random bits. */
+
+ memset(elfregs, 0, sizeof (elfregs));
+
+ /* Note: PS.EXCM is not set while user task is running; its
+ * being set in regs->ps is for exception handling convenience.
+ */
+
+ elfregs->pc = regs->pc;
+ elfregs->ps = (regs->ps & ~(1 << PS_EXCM_BIT));
+ elfregs->lbeg = regs->lbeg;
+ elfregs->lend = regs->lend;
+ elfregs->lcount = regs->lcount;
+ elfregs->sar = regs->sar;
+ elfregs->windowstart = ws;
+
+ live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
+ last = XCHAL_NUM_AREGS - (wm >> 4) * 4;
+ memcpy(elfregs->a, regs->areg, live * 4);
+ memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16);
+}
+
+int dump_fpu(void)
+{
+ return 0;
+}
+
+asmlinkage
+long xtensa_clone(unsigned long clone_flags, unsigned long newsp,
+ void __user *parent_tid, void *child_tls,
+ void __user *child_tid, long a5,
+ struct pt_regs *regs)
+{
+ if (!newsp)
+ newsp = regs->areg[1];
+ return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
+}
+
+/*
+ * xtensa_execve() executes a new program.
+ */
+
+asmlinkage
+long xtensa_execve(const char __user *name,
+ const char __user *const __user *argv,
+ const char __user *const __user *envp,
+ long a3, long a4, long a5,
+ struct pt_regs *regs)
+{
+ long error;
+ char * filename;
+
+ filename = getname(name);
+ error = PTR_ERR(filename);
+ if (IS_ERR(filename))
+ goto out;
+ error = do_execve(filename, argv, envp, regs);
+ putname(filename);
+out:
+ return error;
+}
+
generated by cgit (git 2.34.1) at 2025-01-13 01:38:37 +0000