1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com>
4  * Copyright (C) 2012 Regents of the University of California
5  * Copyright (C) 2017 SiFive
6  */
7 
8 #ifndef _ASM_RISCV_THREAD_INFO_H
9 #define _ASM_RISCV_THREAD_INFO_H
10 
11 #include <asm/page.h>
12 #include <linux/const.h>
13 
14 #ifdef CONFIG_KASAN
15 #define KASAN_STACK_ORDER 1
16 #else
17 #define KASAN_STACK_ORDER 0
18 #endif
19 
20 /* thread information allocation */
21 #ifdef CONFIG_64BIT
22 #define THREAD_SIZE_ORDER	(2 + KASAN_STACK_ORDER)
23 #else
24 #define THREAD_SIZE_ORDER	(1 + KASAN_STACK_ORDER)
25 #endif
26 #define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
27 
28 /*
29  * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
30  * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
31  * assembly.
32  */
33 #ifdef CONFIG_VMAP_STACK
34 #define THREAD_ALIGN            (2 * THREAD_SIZE)
35 #else
36 #define THREAD_ALIGN            THREAD_SIZE
37 #endif
38 
39 #define THREAD_SHIFT            (PAGE_SHIFT + THREAD_SIZE_ORDER)
40 #define OVERFLOW_STACK_SIZE     SZ_4K
41 #define SHADOW_OVERFLOW_STACK_SIZE (1024)
42 
43 #ifndef __ASSEMBLY__
44 
45 extern long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE / sizeof(long)];
46 extern unsigned long spin_shadow_stack;
47 
48 #include <asm/processor.h>
49 #include <asm/csr.h>
50 
51 /*
52  * low level task data that entry.S needs immediate access to
53  * - this struct should fit entirely inside of one cache line
54  * - if the members of this struct changes, the assembly constants
55  *   in asm-offsets.c must be updated accordingly
56  * - thread_info is included in task_struct at an offset of 0.  This means that
57  *   tp points to both thread_info and task_struct.
58  */
59 struct thread_info {
60 	unsigned long		flags;		/* low level flags */
61 	int                     preempt_count;  /* 0=>preemptible, <0=>BUG */
62 	/*
63 	 * These stack pointers are overwritten on every system call or
64 	 * exception.  SP is also saved to the stack it can be recovered when
65 	 * overwritten.
66 	 */
67 	long			kernel_sp;	/* Kernel stack pointer */
68 	long			user_sp;	/* User stack pointer */
69 	int			cpu;
70 	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
71 };
72 
73 /*
74  * macros/functions for gaining access to the thread information structure
75  *
76  * preempt_count needs to be 1 initially, until the scheduler is functional.
77  */
78 #define INIT_THREAD_INFO(tsk)			\
79 {						\
80 	.flags		= 0,			\
81 	.preempt_count	= INIT_PREEMPT_COUNT,	\
82 }
83 
84 #endif /* !__ASSEMBLY__ */
85 
86 /*
87  * thread information flags
88  * - these are process state flags that various assembly files may need to
89  *   access
90  * - pending work-to-be-done flags are in lowest half-word
91  * - other flags in upper half-word(s)
92  */
93 #define TIF_NOTIFY_RESUME	1	/* callback before returning to user */
94 #define TIF_SIGPENDING		2	/* signal pending */
95 #define TIF_NEED_RESCHED	3	/* rescheduling necessary */
96 #define TIF_RESTORE_SIGMASK	4	/* restore signal mask in do_signal() */
97 #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
98 #define TIF_NOTIFY_SIGNAL	9	/* signal notifications exist */
99 #define TIF_UPROBE		10	/* uprobe breakpoint or singlestep */
100 #define TIF_32BIT		11	/* compat-mode 32bit process */
101 
102 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
103 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
104 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
105 #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
106 #define _TIF_UPROBE		(1 << TIF_UPROBE)
107 
108 #define _TIF_WORK_MASK \
109 	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
110 	 _TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
111 
112 #endif /* _ASM_RISCV_THREAD_INFO_H */
113