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Subject[PATCH v3 26/44] metag: Scheduling/Process management
Date
Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
arch/metag/include/asm/thread_info.h | 155 +++++++++++++
arch/metag/kernel/process.c | 422 ++++++++++++++++++++++++++++++++++
2 files changed, 577 insertions(+), 0 deletions(-)
create mode 100644 arch/metag/include/asm/thread_info.h
create mode 100644 arch/metag/kernel/process.c

diff --git a/arch/metag/include/asm/thread_info.h b/arch/metag/include/asm/thread_info.h
new file mode 100644
index 0000000..0ecd34d
--- /dev/null
+++ b/arch/metag/include/asm/thread_info.h
@@ -0,0 +1,155 @@
+/* thread_info.h: Meta low-level thread information
+ *
+ * Copyright (C) 2002 David Howells (dhowells@redhat.com)
+ * - Incorporating suggestions made by Linus Torvalds and Dave Miller
+ *
+ * Meta port by Imagination Technologies
+ */
+
+#ifndef _ASM_THREAD_INFO_H
+#define _ASM_THREAD_INFO_H
+
+#include <linux/compiler.h>
+#include <asm/page.h>
+
+#ifndef __ASSEMBLY__
+#include <asm/processor.h>
+#endif
+
+/*
+ * low level task data that entry.S needs immediate access to
+ * - this struct should fit entirely inside of one cache line
+ * - this struct shares the supervisor stack pages
+ * - if the contents of this structure are changed, the assembly constants must
+ * also be changed
+ */
+#ifndef __ASSEMBLY__
+
+/* This must be 8 byte aligned so we can ensure stack alignment. */
+struct thread_info {
+ struct task_struct *task; /* main task structure */
+ struct exec_domain *exec_domain; /* execution domain */
+ unsigned long flags; /* low level flags */
+ unsigned long status; /* thread-synchronous flags */
+ u32 cpu; /* current CPU */
+ int preempt_count; /* 0 => preemptable, <0 => BUG */
+
+ mm_segment_t addr_limit; /* thread address space */
+ struct restart_block restart_block;
+
+ u8 supervisor_stack[0];
+};
+
+#else /* !__ASSEMBLY__ */
+
+#include <generated/asm-offsets.h>
+
+#endif
+
+#define PREEMPT_ACTIVE 0x10000000
+
+#ifdef CONFIG_4KSTACKS
+#define THREAD_SHIFT 12
+#else
+#define THREAD_SHIFT 13
+#endif
+
+#if THREAD_SHIFT >= PAGE_SHIFT
+#define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT)
+#else
+#define THREAD_SIZE_ORDER 0
+#endif
+
+#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
+
+#define STACK_WARN (THREAD_SIZE/8)
+/*
+ * macros/functions for gaining access to the thread information structure
+ */
+#ifndef __ASSEMBLY__
+
+#define INIT_THREAD_INFO(tsk) \
+{ \
+ .task = &tsk, \
+ .exec_domain = &default_exec_domain, \
+ .flags = 0, \
+ .cpu = 0, \
+ .preempt_count = INIT_PREEMPT_COUNT, \
+ .addr_limit = KERNEL_DS, \
+ .restart_block = { \
+ .fn = do_no_restart_syscall, \
+ }, \
+}
+
+#define init_thread_info (init_thread_union.thread_info)
+#define init_stack (init_thread_union.stack)
+
+/* how to get the current stack pointer from C */
+register unsigned long current_stack_pointer asm("A0StP") __used;
+
+/* how to get the thread information struct from C */
+static inline struct thread_info *current_thread_info(void)
+{
+ return (struct thread_info *)(current_stack_pointer &
+ ~(THREAD_SIZE - 1));
+}
+
+#define __HAVE_ARCH_KSTACK_END
+static inline int kstack_end(void *addr)
+{
+ return addr == (void *) (((unsigned long) addr & ~(THREAD_SIZE - 1))
+ + sizeof(struct thread_info));
+}
+
+#endif
+
+/*
+ * thread information flags
+ * - these are process state flags that various assembly files may need to
+ * access
+ * - pending work-to-be-done flags are in LSW
+ * - other flags in MSW
+ */
+#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
+#define TIF_SIGPENDING 1 /* signal pending */
+#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
+#define TIF_SINGLESTEP 3 /* restore singlestep on return to user
+ mode */
+#define TIF_SYSCALL_AUDIT 4 /* syscall auditing active */
+#define TIF_SECCOMP 5 /* secure computing */
+#define TIF_RESTORE_SIGMASK 6 /* restore signal mask in do_signal() */
+#define TIF_NOTIFY_RESUME 7 /* callback before returning to user */
+#define TIF_POLLING_NRFLAG 8 /* true if poll_idle() is polling
+ TIF_NEED_RESCHED */
+#define TIF_MEMDIE 9 /* is terminating due to OOM killer */
+#define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint instrumentation */
+
+
+#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
+#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
+#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
+#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
+#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
+#define _TIF_SECCOMP (1<<TIF_SECCOMP)
+#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
+#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
+#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
+
+/* work to do in syscall trace */
+#define _TIF_WORK_SYSCALL_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
+ _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
+ _TIF_SYSCALL_TRACEPOINT)
+
+/* work to do on any return to u-space */
+#define _TIF_ALLWORK_MASK (_TIF_SYSCALL_TRACE | _TIF_SIGPENDING | \
+ _TIF_NEED_RESCHED | _TIF_SYSCALL_AUDIT | \
+ _TIF_SINGLESTEP | _TIF_RESTORE_SIGMASK | \
+ _TIF_NOTIFY_RESUME)
+
+/* work to do on interrupt/exception return */
+#define _TIF_WORK_MASK (_TIF_ALLWORK_MASK & ~(_TIF_SYSCALL_TRACE | \
+ _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP))
+
+#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
+
+#endif /* _ASM_THREAD_INFO_H */
diff --git a/arch/metag/kernel/process.c b/arch/metag/kernel/process.c
new file mode 100644
index 0000000..bff8da0
--- /dev/null
+++ b/arch/metag/kernel/process.c
@@ -0,0 +1,422 @@
+/*
+ * Copyright (C) 2005,2006,2007,2008,2009,2010,2011 Imagination Technologies
+ *
+ * This file contains the architecture-dependent parts of process handling.
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/reboot.h>
+#include <linux/elfcore.h>
+#include <linux/fs.h>
+#include <linux/tick.h>
+#include <linux/slab.h>
+#include <linux/mman.h>
+#include <linux/pm.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+#include <asm/core_reg.h>
+#include <asm/user_gateway.h>
+#include <asm/tcm.h>
+#include <asm/traps.h>
+#include <asm/switch_to.h>
+
+void cpu_idle(void)
+{
+ set_thread_flag(TIF_POLLING_NRFLAG);
+
+ while (1) {
+ tick_nohz_idle_enter();
+ rcu_idle_enter();
+
+ while (!need_resched()) {
+#ifdef CONFIG_HOTPLUG_CPU
+ if (cpu_is_offline(smp_processor_id()))
+ cpu_die();
+#endif
+ asm volatile ("SWITCH #0x400000\n"
+ : : : "memory");
+ }
+
+ rcu_idle_exit();
+ tick_nohz_idle_exit();
+ schedule_preempt_disabled();
+ }
+}
+
+void (*pm_power_off)(void);
+EXPORT_SYMBOL(pm_power_off);
+
+void (*soc_restart)(char *cmd);
+void (*soc_halt)(void);
+
+void machine_restart(char *cmd)
+{
+ if (soc_restart)
+ soc_restart(cmd);
+ hard_processor_halt(HALT_OK);
+}
+
+void machine_halt(void)
+{
+ if (soc_halt)
+ soc_halt();
+ smp_send_stop();
+ hard_processor_halt(HALT_OK);
+}
+
+void machine_power_off(void)
+{
+ if (pm_power_off)
+ pm_power_off();
+ smp_send_stop();
+ hard_processor_halt(HALT_OK);
+}
+
+#define FLAG_Z 0x8
+#define FLAG_N 0x4
+#define FLAG_O 0x2
+#define FLAG_C 0x1
+
+void show_regs(struct pt_regs *regs)
+{
+ int i;
+ const char *AX0_names[] = {"A0StP", "A0FrP"};
+ const char *AX1_names[] = {"A1GbP", "A1LbP"};
+
+ const char *DX0_names[] = {
+ "D0Re0",
+ "D0Ar6",
+ "D0Ar4",
+ "D0Ar2",
+ "D0FrT",
+ "D0.5 ",
+ "D0.6 ",
+ "D0.7 "
+ };
+
+ const char *DX1_names[] = {
+ "D1Re0",
+ "D1Ar5",
+ "D1Ar3",
+ "D1Ar1",
+ "D1RtP",
+ "D1.5 ",
+ "D1.6 ",
+ "D1.7 "
+ };
+
+ pr_info(" pt_regs @ %p\n", regs);
+ pr_info(" SaveMask = 0x%04hx\n", regs->ctx.SaveMask);
+ pr_info(" Flags = 0x%04hx (%c%c%c%c)\n", regs->ctx.Flags,
+ regs->ctx.Flags & FLAG_Z ? 'Z' : 'z',
+ regs->ctx.Flags & FLAG_N ? 'N' : 'n',
+ regs->ctx.Flags & FLAG_O ? 'O' : 'o',
+ regs->ctx.Flags & FLAG_C ? 'C' : 'c');
+ pr_info(" TXRPT = 0x%08x\n", regs->ctx.CurrRPT);
+ pr_info(" PC = 0x%08x\n", regs->ctx.CurrPC);
+
+ /* AX regs */
+ for (i = 0; i < 2; i++) {
+ pr_info(" %s = 0x%08x ",
+ AX0_names[i],
+ regs->ctx.AX[i].U0);
+ printk(" %s = 0x%08x\n",
+ AX1_names[i],
+ regs->ctx.AX[i].U1);
+ }
+
+ if (regs->ctx.SaveMask & TBICTX_XEXT_BIT)
+ pr_warn(" Extended state present - AX2.[01] will be WRONG\n");
+
+ /* Special place with AXx.2 */
+ pr_info(" A0.2 = 0x%08x ",
+ regs->ctx.Ext.AX2.U0);
+ printk(" A1.2 = 0x%08x\n",
+ regs->ctx.Ext.AX2.U1);
+
+ /* 'extended' AX regs (nominally, just AXx.3) */
+ for (i = 0; i < (TBICTX_AX_REGS - 3); i++) {
+ pr_info(" A0.%d = 0x%08x ", i + 3, regs->ctx.AX3[i].U0);
+ printk(" A1.%d = 0x%08x\n", i + 3, regs->ctx.AX3[i].U1);
+ }
+
+ for (i = 0; i < 8; i++) {
+ pr_info(" %s = 0x%08x ", DX0_names[i], regs->ctx.DX[i].U0);
+ printk(" %s = 0x%08x\n", DX1_names[i], regs->ctx.DX[i].U1);
+ }
+
+ show_trace(NULL, (unsigned long *)regs->ctx.AX[0].U0, regs);
+}
+
+int copy_thread(unsigned long clone_flags, unsigned long usp,
+ unsigned long arg, struct task_struct *tsk)
+{
+ struct pt_regs *childregs = task_pt_regs(tsk);
+ void *kernel_context = ((void *) childregs +
+ sizeof(struct pt_regs));
+ unsigned long global_base;
+
+ BUG_ON(((unsigned long)childregs) & 0x7);
+ BUG_ON(((unsigned long)kernel_context) & 0x7);
+
+ memset(&tsk->thread.kernel_context, 0,
+ sizeof(tsk->thread.kernel_context));
+
+ tsk->thread.kernel_context = __TBISwitchInit(kernel_context,
+ ret_from_fork,
+ 0, 0);
+
+ if (unlikely(tsk->flags & PF_KTHREAD)) {
+ /*
+ * Make sure we don't leak any kernel data to child's regs
+ * if kernel thread becomes a userspace thread in the future
+ */
+ memset(childregs, 0 , sizeof(struct pt_regs));
+
+ asm volatile ("MOV %0,A1GbP\n" : "=r" (global_base));
+ childregs->ctx.AX[0].U1 = (unsigned long) global_base;
+ childregs->ctx.AX[0].U0 = (unsigned long) kernel_context;
+ /* Set D1Ar1=arg and D1RtP=usp (fn) */
+ childregs->ctx.DX[4].U1 = usp;
+ childregs->ctx.DX[3].U1 = arg;
+ tsk->thread.int_depth = 2;
+ return 0;
+ }
+ /*
+ * Get a pointer to where the new child's register block should have
+ * been pushed.
+ * The Meta's stack grows upwards, and the context is the the first
+ * thing to be pushed by TBX (phew)
+ */
+ *childregs = *current_pt_regs();
+ /* Set the correct stack for the clone mode */
+ if (usp)
+ childregs->ctx.AX[0].U0 = ALIGN(usp, 8);
+ tsk->thread.int_depth = 1;
+
+ /* set return value for child process */
+ childregs->ctx.DX[0].U0 = 0;
+
+ /* The TLS pointer is passed as an argument to sys_clone. */
+ if (clone_flags & CLONE_SETTLS)
+ tsk->thread.tls_ptr =
+ (__force void __user *)childregs->ctx.DX[1].U1;
+
+#ifdef CONFIG_METAG_FPU
+ if (tsk->thread.fpu_context) {
+ struct meta_fpu_context *ctx;
+
+ ctx = kmemdup(tsk->thread.fpu_context,
+ sizeof(struct meta_fpu_context), GFP_ATOMIC);
+ tsk->thread.fpu_context = ctx;
+ }
+#endif
+
+#ifdef CONFIG_METAG_DSP
+ if (tsk->thread.dsp_context) {
+ struct meta_ext_context *ctx;
+ int i;
+
+ ctx = kmemdup(tsk->thread.dsp_context,
+ sizeof(struct meta_ext_context), GFP_ATOMIC);
+ for (i = 0; i < 2; i++)
+ ctx->ram[i] = kmemdup(ctx->ram[i], ctx->ram_sz[i],
+ GFP_ATOMIC);
+ tsk->thread.dsp_context = ctx;
+ }
+#endif
+
+ return 0;
+}
+
+#ifdef CONFIG_METAG_FPU
+static void alloc_fpu_context(struct thread_struct *thread)
+{
+ thread->fpu_context = kzalloc(sizeof(struct meta_fpu_context),
+ GFP_ATOMIC);
+}
+
+static void clear_fpu(struct thread_struct *thread)
+{
+ thread->user_flags &= ~TBICTX_FPAC_BIT;
+ kfree(thread->fpu_context);
+ thread->fpu_context = NULL;
+}
+#else
+static void clear_fpu(struct thread_struct *thread)
+{
+}
+#endif
+
+#ifdef CONFIG_METAG_DSP
+static void clear_dsp(struct thread_struct *thread)
+{
+ if (thread->dsp_context) {
+ kfree(thread->dsp_context->ram[0]);
+ kfree(thread->dsp_context->ram[1]);
+
+ kfree(thread->dsp_context);
+
+ thread->dsp_context = NULL;
+ }
+
+ __core_reg_set(D0.8, 0);
+}
+#else
+static void clear_dsp(struct thread_struct *thread)
+{
+}
+#endif
+
+struct task_struct *__sched __switch_to(struct task_struct *prev,
+ struct task_struct *next)
+{
+ TBIRES to, from;
+
+ to.Switch.pCtx = next->thread.kernel_context;
+ to.Switch.pPara = prev;
+
+#ifdef CONFIG_METAG_FPU
+ if (prev->thread.user_flags & TBICTX_FPAC_BIT) {
+ struct pt_regs *regs = task_pt_regs(prev);
+ TBIRES state;
+
+ state.Sig.SaveMask = prev->thread.user_flags;
+ state.Sig.pCtx = &regs->ctx;
+
+ if (!prev->thread.fpu_context)
+ alloc_fpu_context(&prev->thread);
+ if (prev->thread.fpu_context)
+ __TBICtxFPUSave(state, prev->thread.fpu_context);
+ }
+ /*
+ * Force a restore of the FPU context next time this process is
+ * scheduled.
+ */
+ if (prev->thread.fpu_context)
+ prev->thread.fpu_context->needs_restore = true;
+#endif
+
+
+ from = __TBISwitch(to, &prev->thread.kernel_context);
+
+ /* Restore TLS pointer for this process. */
+ set_gateway_tls(current->thread.tls_ptr);
+
+ return (struct task_struct *) from.Switch.pPara;
+}
+
+void flush_thread(void)
+{
+ clear_fpu(&current->thread);
+ clear_dsp(&current->thread);
+}
+
+/*
+ * Free current thread data structures etc.
+ */
+void exit_thread(void)
+{
+ clear_fpu(&current->thread);
+ clear_dsp(&current->thread);
+}
+
+/* TODO: figure out how to unwind the kernel stack here to figure out
+ * where we went to sleep. */
+unsigned long get_wchan(struct task_struct *p)
+{
+ return 0;
+}
+
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
+{
+ /* Returning 0 indicates that the FPU state was not stored (as it was
+ * not in use) */
+ return 0;
+}
+
+#ifdef CONFIG_METAG_USER_TCM
+
+#define ELF_MIN_ALIGN PAGE_SIZE
+
+#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
+#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
+#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
+
+#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
+
+unsigned long __metag_elf_map(struct file *filep, unsigned long addr,
+ struct elf_phdr *eppnt, int prot, int type,
+ unsigned long total_size)
+{
+ unsigned long map_addr, size;
+ unsigned long page_off = ELF_PAGEOFFSET(eppnt->p_vaddr);
+ unsigned long raw_size = eppnt->p_filesz + page_off;
+ unsigned long off = eppnt->p_offset - page_off;
+ unsigned int tcm_tag;
+ addr = ELF_PAGESTART(addr);
+ size = ELF_PAGEALIGN(raw_size);
+
+ /* mmap() will return -EINVAL if given a zero size, but a
+ * segment with zero filesize is perfectly valid */
+ if (!size)
+ return addr;
+
+ tcm_tag = tcm_lookup_tag(addr);
+
+ if (tcm_tag != TCM_INVALID_TAG)
+ type &= ~MAP_FIXED;
+
+ /*
+ * total_size is the size of the ELF (interpreter) image.
+ * The _first_ mmap needs to know the full size, otherwise
+ * randomization might put this image into an overlapping
+ * position with the ELF binary image. (since size < total_size)
+ * So we first map the 'big' image - and unmap the remainder at
+ * the end. (which unmap is needed for ELF images with holes.)
+ */
+ if (total_size) {
+ total_size = ELF_PAGEALIGN(total_size);
+ map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
+ if (!BAD_ADDR(map_addr))
+ vm_munmap(map_addr+size, total_size-size);
+ } else
+ map_addr = vm_mmap(filep, addr, size, prot, type, off);
+
+ if (!BAD_ADDR(map_addr) && tcm_tag != TCM_INVALID_TAG) {
+ struct tcm_allocation *tcm;
+ unsigned long tcm_addr;
+
+ tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
+ if (!tcm)
+ return -ENOMEM;
+
+ tcm_addr = tcm_alloc(tcm_tag, raw_size);
+ if (tcm_addr != addr) {
+ kfree(tcm);
+ return -ENOMEM;
+ }
+
+ tcm->tag = tcm_tag;
+ tcm->addr = tcm_addr;
+ tcm->size = raw_size;
+
+ list_add(&tcm->list, &current->mm->context.tcm);
+
+ eppnt->p_vaddr = map_addr;
+ if (copy_from_user((void *) addr, (void __user *) map_addr,
+ raw_size))
+ return -EFAULT;
+ }
+
+ return map_addr;
+}
+#endif
--
1.7.7.6



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