[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 3
The attached patches provides part 3 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Chris Zankel
committed by
Linus Torvalds
Linus Torvalds
parent
4bedea9454
commit
5a0015d626
482
arch/xtensa/kernel/process.c
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482
arch/xtensa/kernel/process.c
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@@ -0,0 +1,482 @@
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// TODO verify coprocessor handling
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/*
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* arch/xtensa/kernel/process.c
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*
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* Xtensa Processor version.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2001 - 2005 Tensilica Inc.
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*
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* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
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* Chris Zankel <chris@zankel.net>
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* Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
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* Kevin Chea
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/elf.h>
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#include <linux/init.h>
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#include <linux/prctl.h>
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#include <linux/init_task.h>
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#include <linux/module.h>
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#include <linux/mqueue.h>
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#include <asm/pgtable.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/platform.h>
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#include <asm/mmu.h>
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#include <asm/irq.h>
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#include <asm/atomic.h>
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#include <asm/offsets.h>
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#include <asm/coprocessor.h>
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extern void ret_from_fork(void);
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static struct fs_struct init_fs = INIT_FS;
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static struct files_struct init_files = INIT_FILES;
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static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
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static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
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struct mm_struct init_mm = INIT_MM(init_mm);
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EXPORT_SYMBOL(init_mm);
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union thread_union init_thread_union
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__attribute__((__section__(".data.init_task"))) =
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{ INIT_THREAD_INFO(init_task) };
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struct task_struct init_task = INIT_TASK(init_task);
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EXPORT_SYMBOL(init_task);
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struct task_struct *current_set[NR_CPUS] = {&init_task, };
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#if XCHAL_CP_NUM > 0
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/*
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* Coprocessor ownership.
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*/
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coprocessor_info_t coprocessor_info[] = {
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{ 0, XTENSA_CPE_CP0_OFFSET },
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{ 0, XTENSA_CPE_CP1_OFFSET },
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{ 0, XTENSA_CPE_CP2_OFFSET },
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{ 0, XTENSA_CPE_CP3_OFFSET },
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{ 0, XTENSA_CPE_CP4_OFFSET },
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{ 0, XTENSA_CPE_CP5_OFFSET },
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{ 0, XTENSA_CPE_CP6_OFFSET },
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{ 0, XTENSA_CPE_CP7_OFFSET },
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};
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#endif
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/*
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* Powermanagement idle function, if any is provided by the platform.
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*/
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void cpu_idle(void)
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{
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local_irq_enable();
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/* endless idle loop with no priority at all */
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while (1) {
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while (!need_resched())
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platform_idle();
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preempt_enable();
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schedule();
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}
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}
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/*
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* Free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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release_coprocessors(current); /* Empty macro if no CPs are defined */
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}
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void flush_thread(void)
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{
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release_coprocessors(current); /* Empty macro if no CPs are defined */
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}
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/*
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* Copy thread.
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*
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* The stack layout for the new thread looks like this:
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*
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* +------------------------+ <- sp in childregs (= tos)
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* | childregs |
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* +------------------------+ <- thread.sp = sp in dummy-frame
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* | dummy-frame | (saved in dummy-frame spill-area)
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* +------------------------+
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*
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* We create a dummy frame to return to ret_from_fork:
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* a0 points to ret_from_fork (simulating a call4)
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* sp points to itself (thread.sp)
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* a2, a3 are unused.
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*
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* Note: This is a pristine frame, so we don't need any spill region on top of
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* childregs.
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*/
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int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
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unsigned long unused,
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struct task_struct * p, struct pt_regs * regs)
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{
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struct pt_regs *childregs;
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unsigned long tos;
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int user_mode = user_mode(regs);
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/* Set up new TSS. */
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tos = (unsigned long)p->thread_info + THREAD_SIZE;
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if (user_mode)
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childregs = (struct pt_regs*)(tos - PT_USER_SIZE);
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else
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childregs = (struct pt_regs*)tos - 1;
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*childregs = *regs;
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/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
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*((int*)childregs - 3) = (unsigned long)childregs;
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*((int*)childregs - 4) = 0;
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childregs->areg[1] = tos;
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childregs->areg[2] = 0;
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p->set_child_tid = p->clear_child_tid = NULL;
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p->thread.ra = MAKE_RA_FOR_CALL((unsigned long)ret_from_fork, 0x1);
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p->thread.sp = (unsigned long)childregs;
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if (user_mode(regs)) {
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int len = childregs->wmask & ~0xf;
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childregs->areg[1] = usp;
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memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],
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®s->areg[XCHAL_NUM_AREGS - len/4], len);
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if (clone_flags & CLONE_SETTLS)
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childregs->areg[2] = childregs->areg[6];
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} else {
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/* In kernel space, we start a new thread with a new stack. */
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childregs->wmask = 1;
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}
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return 0;
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}
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/*
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* Create a kernel thread
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*/
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int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
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{
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long retval;
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__asm__ __volatile__
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("mov a5, %4\n\t" /* preserve fn in a5 */
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"mov a6, %3\n\t" /* preserve and setup arg in a6 */
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"movi a2, %1\n\t" /* load __NR_clone for syscall*/
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"mov a3, sp\n\t" /* sp check and sys_clone */
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"mov a4, %5\n\t" /* load flags for syscall */
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"syscall\n\t"
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"beq a3, sp, 1f\n\t" /* branch if parent */
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"callx4 a5\n\t" /* call fn */
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"movi a2, %2\n\t" /* load __NR_exit for syscall */
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"mov a3, a6\n\t" /* load fn return value */
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"syscall\n"
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"1:\n\t"
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"mov %0, a2\n\t" /* parent returns zero */
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:"=r" (retval)
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:"i" (__NR_clone), "i" (__NR_exit),
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"r" (arg), "r" (fn),
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"r" (flags | CLONE_VM)
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: "a2", "a3", "a4", "a5", "a6" );
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return retval;
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}
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/*
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* These bracket the sleeping functions..
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*/
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long sp, pc;
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unsigned long stack_page = (unsigned long) p->thread_info;
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int count = 0;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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sp = p->thread.sp;
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pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
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do {
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if (sp < stack_page + sizeof(struct task_struct) ||
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sp >= (stack_page + THREAD_SIZE) ||
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pc == 0)
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return 0;
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if (!in_sched_functions(pc))
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return pc;
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/* Stack layout: sp-4: ra, sp-3: sp' */
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pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);
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sp = *(unsigned long *)sp - 3;
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} while (count++ < 16);
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return 0;
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}
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/*
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* do_copy_regs() gathers information from 'struct pt_regs' and
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* 'current->thread.areg[]' to fill in the xtensa_gregset_t
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* structure.
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*
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* xtensa_gregset_t and 'struct pt_regs' are vastly different formats
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* of processor registers. Besides different ordering,
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* xtensa_gregset_t contains non-live register information that
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* 'struct pt_regs' does not. Exception handling (primarily) uses
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* 'struct pt_regs'. Core files and ptrace use xtensa_gregset_t.
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*
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*/
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void do_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs,
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struct task_struct *tsk)
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{
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int i, n, wb_offset;
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elfregs->xchal_config_id0 = XCHAL_HW_CONFIGID0;
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elfregs->xchal_config_id1 = XCHAL_HW_CONFIGID1;
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__asm__ __volatile__ ("rsr %0, 176\n" : "=a" (i));
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elfregs->cpux = i;
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__asm__ __volatile__ ("rsr %0, 208\n" : "=a" (i));
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elfregs->cpuy = i;
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/* Note: PS.EXCM is not set while user task is running; its
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* being set in regs->ps is for exception handling convenience.
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*/
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elfregs->pc = regs->pc;
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elfregs->ps = (regs->ps & ~XCHAL_PS_EXCM_MASK);
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elfregs->exccause = regs->exccause;
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elfregs->excvaddr = regs->excvaddr;
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elfregs->windowbase = regs->windowbase;
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elfregs->windowstart = regs->windowstart;
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elfregs->lbeg = regs->lbeg;
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elfregs->lend = regs->lend;
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elfregs->lcount = regs->lcount;
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elfregs->sar = regs->sar;
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elfregs->syscall = regs->syscall;
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/* Copy register file.
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* The layout looks like this:
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*
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* | a0 ... a15 | Z ... Z | arX ... arY |
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* current window unused saved frames
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*/
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memset (elfregs->ar, 0, sizeof(elfregs->ar));
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wb_offset = regs->windowbase * 4;
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n = (regs->wmask&1)? 4 : (regs->wmask&2)? 8 : (regs->wmask&4)? 12 : 16;
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for (i = 0; i < n; i++)
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elfregs->ar[(wb_offset + i) % XCHAL_NUM_AREGS] = regs->areg[i];
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n = (regs->wmask >> 4) * 4;
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for (i = XCHAL_NUM_AREGS - n; n > 0; i++, n--)
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elfregs->ar[(wb_offset + i) % XCHAL_NUM_AREGS] = regs->areg[i];
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}
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void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs)
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{
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do_copy_regs ((xtensa_gregset_t *)elfregs, regs, current);
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}
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/* The inverse of do_copy_regs(). No error or sanity checking. */
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void do_restore_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs,
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struct task_struct *tsk)
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{
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int i, n, wb_offset;
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/* Note: PS.EXCM is not set while user task is running; it
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* needs to be set in regs->ps is for exception handling convenience.
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*/
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regs->pc = elfregs->pc;
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regs->ps = (elfregs->ps | XCHAL_PS_EXCM_MASK);
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regs->exccause = elfregs->exccause;
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regs->excvaddr = elfregs->excvaddr;
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regs->windowbase = elfregs->windowbase;
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regs->windowstart = elfregs->windowstart;
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regs->lbeg = elfregs->lbeg;
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regs->lend = elfregs->lend;
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regs->lcount = elfregs->lcount;
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regs->sar = elfregs->sar;
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regs->syscall = elfregs->syscall;
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/* Clear everything. */
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memset (regs->areg, 0, sizeof(regs->areg));
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/* Copy regs from live window frame. */
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wb_offset = regs->windowbase * 4;
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n = (regs->wmask&1)? 4 : (regs->wmask&2)? 8 : (regs->wmask&4)? 12 : 16;
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for (i = 0; i < n; i++)
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regs->areg[(wb_offset+i) % XCHAL_NUM_AREGS] = elfregs->ar[i];
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n = (regs->wmask >> 4) * 4;
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for (i = XCHAL_NUM_AREGS - n; n > 0; i++, n--)
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regs->areg[(wb_offset+i) % XCHAL_NUM_AREGS] = elfregs->ar[i];
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}
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/*
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* do_save_fpregs() gathers information from 'struct pt_regs' and
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* 'current->thread' to fill in the elf_fpregset_t structure.
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*
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* Core files and ptrace use elf_fpregset_t.
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*/
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void do_save_fpregs (elf_fpregset_t *fpregs, struct pt_regs *regs,
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struct task_struct *tsk)
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{
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#if XCHAL_HAVE_CP
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extern unsigned char _xtensa_reginfo_tables[];
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extern unsigned _xtensa_reginfo_table_size;
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int i;
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unsigned long flags;
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/* Before dumping coprocessor state from memory,
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* ensure any live coprocessor contents for this
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* task are first saved to memory:
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*/
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local_irq_save(flags);
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for (i = 0; i < XCHAL_CP_MAX; i++) {
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if (tsk == coprocessor_info[i].owner) {
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enable_coprocessor(i);
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save_coprocessor_registers(
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tsk->thread.cp_save+coprocessor_info[i].offset,i);
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disable_coprocessor(i);
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}
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}
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local_irq_restore(flags);
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/* Now dump coprocessor & extra state: */
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memcpy((unsigned char*)fpregs,
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_xtensa_reginfo_tables, _xtensa_reginfo_table_size);
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memcpy((unsigned char*)fpregs + _xtensa_reginfo_table_size,
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tsk->thread.cp_save, XTENSA_CP_EXTRA_SIZE);
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#endif
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}
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/*
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* The inverse of do_save_fpregs().
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* Copies coprocessor and extra state from fpregs into regs and tsk->thread.
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* Returns 0 on success, non-zero if layout doesn't match.
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*/
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int do_restore_fpregs (elf_fpregset_t *fpregs, struct pt_regs *regs,
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struct task_struct *tsk)
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{
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#if XCHAL_HAVE_CP
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extern unsigned char _xtensa_reginfo_tables[];
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extern unsigned _xtensa_reginfo_table_size;
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int i;
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unsigned long flags;
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/* Make sure save area layouts match.
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* FIXME: in the future we could allow restoring from
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* a different layout of the same registers, by comparing
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* fpregs' table with _xtensa_reginfo_tables and matching
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* entries and copying registers one at a time.
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* Not too sure yet whether that's very useful.
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*/
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if( memcmp((unsigned char*)fpregs,
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_xtensa_reginfo_tables, _xtensa_reginfo_table_size) ) {
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return -1;
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}
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/* Before restoring coprocessor state from memory,
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* ensure any live coprocessor contents for this
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* task are first invalidated.
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*/
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local_irq_save(flags);
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for (i = 0; i < XCHAL_CP_MAX; i++) {
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if (tsk == coprocessor_info[i].owner) {
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enable_coprocessor(i);
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save_coprocessor_registers(
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tsk->thread.cp_save+coprocessor_info[i].offset,i);
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coprocessor_info[i].owner = 0;
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disable_coprocessor(i);
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}
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}
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local_irq_restore(flags);
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/* Now restore coprocessor & extra state: */
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memcpy(tsk->thread.cp_save,
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(unsigned char*)fpregs + _xtensa_reginfo_table_size,
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XTENSA_CP_EXTRA_SIZE);
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#endif
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return 0;
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}
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/*
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* Fill in the CP structure for a core dump for a particular task.
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*/
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int
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dump_task_fpu(struct pt_regs *regs, struct task_struct *task, elf_fpregset_t *r)
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{
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/* see asm/coprocessor.h for this magic number 16 */
|
||||
#if TOTAL_CPEXTRA_SIZE > 16
|
||||
do_save_fpregs (r, regs, task);
|
||||
|
||||
/* For now, bit 16 means some extra state may be present: */
|
||||
// FIXME!! need to track to return more accurate mask
|
||||
return 0x10000 | XCHAL_CP_MASK;
|
||||
#else
|
||||
return 0; /* no coprocessors active on this processor */
|
||||
#endif
|
||||
}
|
||||
|
||||
/*
|
||||
* Fill in the CP structure for a core dump.
|
||||
* This includes any FPU coprocessor.
|
||||
* Here, we dump all coprocessors, and other ("extra") custom state.
|
||||
*
|
||||
* This function is called by elf_core_dump() in fs/binfmt_elf.c
|
||||
* (in which case 'regs' comes from calls to do_coredump, see signals.c).
|
||||
*/
|
||||
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
|
||||
{
|
||||
return dump_task_fpu(regs, current, r);
|
||||
}
|
||||
Reference in New Issue
Block a user