| 1 | |
| 2 | #include <linux/sched/signal.h>
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| 3 | #include <linux/sched/task.h>
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| 4 | #include <linux/sched/task_stack.h>
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| 5 | #include <linux/slab.h>
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| 6 | #include <asm/processor.h>
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| 7 | #include <asm/fpu.h>
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| 8 | #include <asm/traps.h>
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| 9 | #include <asm/ptrace.h>
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| 10 |
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| 11 | int init_fpu(struct task_struct *tsk)
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| 12 | {
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| 13 | if (tsk_used_math(tsk)) {
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| 14 | if ((boot_cpu_data.flags & CPU_HAS_FPU) && tsk == current)
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| 15 | unlazy_fpu(tsk, task_pt_regs(tsk));
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| 16 | return 0;
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| 17 | }
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| 18 |
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| 19 | |
| 20 | * Memory allocation at the first usage of the FPU and other state.
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| 21 |
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| 22 | if (!tsk->thread.xstate) {
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| 23 | tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
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| 24 | GFP_KERNEL);
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| 25 | if (!tsk->thread.xstate)
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| 26 | return -ENOMEM;
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| 27 | }
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| 28 |
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| 29 | if (boot_cpu_data.flags & CPU_HAS_FPU) {
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| 30 | struct sh_fpu_hard_struct *fp = &tsk->thread.xstate->hardfpu;
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| 31 | memset(fp, 0, xstate_size);
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| 32 | fp->fpscr = FPSCR_INIT;
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| 33 | } else {
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| 34 | struct sh_fpu_soft_struct *fp = &tsk->thread.xstate->softfpu;
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| 35 | memset(fp, 0, xstate_size);
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| 36 | fp->fpscr = FPSCR_INIT;
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| 37 | }
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| 38 |
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| 39 | set_stopped_child_used_math(tsk);
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| 40 | return 0;
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| 41 | }
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| 42 |
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| 43 | #ifdef CONFIG_SH_FPU
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| 44 | void __fpu_state_restore(void)
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| 45 | {
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| 46 | struct task_struct *tsk = current;
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| 47 |
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| 48 | restore_fpu(tsk);
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| 49 |
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| 50 | task_thread_info(tsk)->status |= TS_USEDFPU;
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| 51 | tsk->thread.fpu_counter++;
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| 52 | }
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| 53 |
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| 54 | void fpu_state_restore(struct pt_regs *regs)
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| 55 | {
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| 56 | struct task_struct *tsk = current;
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| 57 |
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| 58 | if (unlikely(!user_mode(regs))) {
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| 59 | printk(KERN_ERR "BUG: FPU is used in kernel mode.\n");
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| 60 | BUG();
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| 61 | return;
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| 62 | }
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| 63 |
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| 64 | if (!tsk_used_math(tsk)) {
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| 65 | int ret;
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| 66 | |
| 67 | * does a slab alloc which can sleep
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| 68 |
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| 69 | local_irq_enable();
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| 70 | ret = init_fpu(tsk);
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| 71 | local_irq_disable();
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| 72 | if (ret) {
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| 73 | |
| 74 | * ran out of memory!
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| 75 |
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| 76 | force_sig(SIGKILL);
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| 77 | return;
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| 78 | }
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| 79 | }
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| 80 |
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| 81 | grab_fpu(regs);
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| 82 |
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| 83 | __fpu_state_restore();
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| 84 | }
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| 85 |
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| 86 | BUILD_TRAP_HANDLER(fpu_state_restore)
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| 87 | {
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| 88 | TRAP_HANDLER_DECL;
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| 89 |
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| 90 | fpu_state_restore(regs);
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| 91 | }
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| 92 | #endif
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