1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/mm.h> 3 #include <linux/kernel.h> 4 #include <linux/slab.h> 5 #include <linux/sched/signal.h> 6 #include <linux/sched/task_stack.h> 7 #include <linux/export.h> 8 #include <linux/stackprotector.h> 9 #include <asm/fpu.h> 10 #include <asm/ptrace.h> 11 12 struct kmem_cache *task_xstate_cachep = NULL; 13 unsigned int xstate_size; 14 15 #ifdef CONFIG_STACKPROTECTOR 16 unsigned long __stack_chk_guard __read_mostly; 17 EXPORT_SYMBOL(__stack_chk_guard); 18 #endif 19 20 /* 21 * this gets called so that we can store lazy state into memory and copy the 22 * current task into the new thread. 23 */ 24 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 25 { 26 unlazy_fpu(src, task_pt_regs(src)); 27 *dst = *src; 28 29 if (src->thread.xstate) { 30 dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, 31 GFP_KERNEL); 32 if (!dst->thread.xstate) 33 return -ENOMEM; 34 memcpy(dst->thread.xstate, src->thread.xstate, xstate_size); 35 } 36 37 return 0; 38 } 39 40 void free_thread_xstate(struct task_struct *tsk) 41 { 42 if (tsk->thread.xstate) { 43 kmem_cache_free(task_xstate_cachep, tsk->thread.xstate); 44 tsk->thread.xstate = NULL; 45 } 46 } 47 48 void arch_release_task_struct(struct task_struct *tsk) 49 { 50 free_thread_xstate(tsk); 51 } 52 53 void arch_task_cache_init(void) 54 { 55 if (!xstate_size) 56 return; 57 58 task_xstate_cachep = kmem_cache_create("task_xstate", xstate_size, 59 __alignof__(union thread_xstate), 60 SLAB_PANIC, NULL); 61 } 62 63 #ifdef CONFIG_SH_FPU_EMU 64 # define HAVE_SOFTFP 1 65 #else 66 # define HAVE_SOFTFP 0 67 #endif 68 69 void init_thread_xstate(void) 70 { 71 if (boot_cpu_data.flags & CPU_HAS_FPU) 72 xstate_size = sizeof(struct sh_fpu_hard_struct); 73 else if (HAVE_SOFTFP) 74 xstate_size = sizeof(struct sh_fpu_soft_struct); 75 else 76 xstate_size = 0; 77 } 78