xref: /openbmc/linux/arch/arm64/include/asm/processor.h (revision 151f4e2b)
1 /*
2  * Based on arch/arm/include/asm/processor.h
3  *
4  * Copyright (C) 1995-1999 Russell King
5  * Copyright (C) 2012 ARM Ltd.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 #ifndef __ASM_PROCESSOR_H
20 #define __ASM_PROCESSOR_H
21 
22 #define KERNEL_DS		UL(-1)
23 #define USER_DS			((UL(1) << MAX_USER_VA_BITS) - 1)
24 
25 /*
26  * On arm64 systems, unaligned accesses by the CPU are cheap, and so there is
27  * no point in shifting all network buffers by 2 bytes just to make some IP
28  * header fields appear aligned in memory, potentially sacrificing some DMA
29  * performance on some platforms.
30  */
31 #define NET_IP_ALIGN	0
32 
33 #ifndef __ASSEMBLY__
34 #ifdef __KERNEL__
35 
36 #include <linux/build_bug.h>
37 #include <linux/cache.h>
38 #include <linux/init.h>
39 #include <linux/stddef.h>
40 #include <linux/string.h>
41 
42 #include <asm/alternative.h>
43 #include <asm/cpufeature.h>
44 #include <asm/hw_breakpoint.h>
45 #include <asm/lse.h>
46 #include <asm/pgtable-hwdef.h>
47 #include <asm/pointer_auth.h>
48 #include <asm/ptrace.h>
49 #include <asm/types.h>
50 
51 /*
52  * TASK_SIZE - the maximum size of a user space task.
53  * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area.
54  */
55 
56 #define DEFAULT_MAP_WINDOW_64	(UL(1) << VA_BITS)
57 #define TASK_SIZE_64		(UL(1) << vabits_user)
58 
59 #ifdef CONFIG_COMPAT
60 #if defined(CONFIG_ARM64_64K_PAGES) && defined(CONFIG_KUSER_HELPERS)
61 /*
62  * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied
63  * by the compat vectors page.
64  */
65 #define TASK_SIZE_32		UL(0x100000000)
66 #else
67 #define TASK_SIZE_32		(UL(0x100000000) - PAGE_SIZE)
68 #endif /* CONFIG_ARM64_64K_PAGES */
69 #define TASK_SIZE		(test_thread_flag(TIF_32BIT) ? \
70 				TASK_SIZE_32 : TASK_SIZE_64)
71 #define TASK_SIZE_OF(tsk)	(test_tsk_thread_flag(tsk, TIF_32BIT) ? \
72 				TASK_SIZE_32 : TASK_SIZE_64)
73 #define DEFAULT_MAP_WINDOW	(test_thread_flag(TIF_32BIT) ? \
74 				TASK_SIZE_32 : DEFAULT_MAP_WINDOW_64)
75 #else
76 #define TASK_SIZE		TASK_SIZE_64
77 #define DEFAULT_MAP_WINDOW	DEFAULT_MAP_WINDOW_64
78 #endif /* CONFIG_COMPAT */
79 
80 #ifdef CONFIG_ARM64_FORCE_52BIT
81 #define STACK_TOP_MAX		TASK_SIZE_64
82 #define TASK_UNMAPPED_BASE	(PAGE_ALIGN(TASK_SIZE / 4))
83 #else
84 #define STACK_TOP_MAX		DEFAULT_MAP_WINDOW_64
85 #define TASK_UNMAPPED_BASE	(PAGE_ALIGN(DEFAULT_MAP_WINDOW / 4))
86 #endif /* CONFIG_ARM64_FORCE_52BIT */
87 
88 #ifdef CONFIG_COMPAT
89 #define AARCH32_VECTORS_BASE	0xffff0000
90 #define STACK_TOP		(test_thread_flag(TIF_32BIT) ? \
91 				AARCH32_VECTORS_BASE : STACK_TOP_MAX)
92 #else
93 #define STACK_TOP		STACK_TOP_MAX
94 #endif /* CONFIG_COMPAT */
95 
96 #ifndef CONFIG_ARM64_FORCE_52BIT
97 #define arch_get_mmap_end(addr) ((addr > DEFAULT_MAP_WINDOW) ? TASK_SIZE :\
98 				DEFAULT_MAP_WINDOW)
99 
100 #define arch_get_mmap_base(addr, base) ((addr > DEFAULT_MAP_WINDOW) ? \
101 					base + TASK_SIZE - DEFAULT_MAP_WINDOW :\
102 					base)
103 #endif /* CONFIG_ARM64_FORCE_52BIT */
104 
105 extern phys_addr_t arm64_dma_phys_limit;
106 #define ARCH_LOW_ADDRESS_LIMIT	(arm64_dma_phys_limit - 1)
107 
108 struct debug_info {
109 #ifdef CONFIG_HAVE_HW_BREAKPOINT
110 	/* Have we suspended stepping by a debugger? */
111 	int			suspended_step;
112 	/* Allow breakpoints and watchpoints to be disabled for this thread. */
113 	int			bps_disabled;
114 	int			wps_disabled;
115 	/* Hardware breakpoints pinned to this task. */
116 	struct perf_event	*hbp_break[ARM_MAX_BRP];
117 	struct perf_event	*hbp_watch[ARM_MAX_WRP];
118 #endif
119 };
120 
121 struct cpu_context {
122 	unsigned long x19;
123 	unsigned long x20;
124 	unsigned long x21;
125 	unsigned long x22;
126 	unsigned long x23;
127 	unsigned long x24;
128 	unsigned long x25;
129 	unsigned long x26;
130 	unsigned long x27;
131 	unsigned long x28;
132 	unsigned long fp;
133 	unsigned long sp;
134 	unsigned long pc;
135 };
136 
137 struct thread_struct {
138 	struct cpu_context	cpu_context;	/* cpu context */
139 
140 	/*
141 	 * Whitelisted fields for hardened usercopy:
142 	 * Maintainers must ensure manually that this contains no
143 	 * implicit padding.
144 	 */
145 	struct {
146 		unsigned long	tp_value;	/* TLS register */
147 		unsigned long	tp2_value;
148 		struct user_fpsimd_state fpsimd_state;
149 	} uw;
150 
151 	unsigned int		fpsimd_cpu;
152 	void			*sve_state;	/* SVE registers, if any */
153 	unsigned int		sve_vl;		/* SVE vector length */
154 	unsigned int		sve_vl_onexec;	/* SVE vl after next exec */
155 	unsigned long		fault_address;	/* fault info */
156 	unsigned long		fault_code;	/* ESR_EL1 value */
157 	struct debug_info	debug;		/* debugging */
158 #ifdef CONFIG_ARM64_PTR_AUTH
159 	struct ptrauth_keys	keys_user;
160 #endif
161 };
162 
163 static inline void arch_thread_struct_whitelist(unsigned long *offset,
164 						unsigned long *size)
165 {
166 	/* Verify that there is no padding among the whitelisted fields: */
167 	BUILD_BUG_ON(sizeof_field(struct thread_struct, uw) !=
168 		     sizeof_field(struct thread_struct, uw.tp_value) +
169 		     sizeof_field(struct thread_struct, uw.tp2_value) +
170 		     sizeof_field(struct thread_struct, uw.fpsimd_state));
171 
172 	*offset = offsetof(struct thread_struct, uw);
173 	*size = sizeof_field(struct thread_struct, uw);
174 }
175 
176 #ifdef CONFIG_COMPAT
177 #define task_user_tls(t)						\
178 ({									\
179 	unsigned long *__tls;						\
180 	if (is_compat_thread(task_thread_info(t)))			\
181 		__tls = &(t)->thread.uw.tp2_value;			\
182 	else								\
183 		__tls = &(t)->thread.uw.tp_value;			\
184 	__tls;								\
185  })
186 #else
187 #define task_user_tls(t)	(&(t)->thread.uw.tp_value)
188 #endif
189 
190 /* Sync TPIDR_EL0 back to thread_struct for current */
191 void tls_preserve_current_state(void);
192 
193 #define INIT_THREAD {				\
194 	.fpsimd_cpu = NR_CPUS,			\
195 }
196 
197 static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
198 {
199 	memset(regs, 0, sizeof(*regs));
200 	forget_syscall(regs);
201 	regs->pc = pc;
202 
203 	if (system_uses_irq_prio_masking())
204 		regs->pmr_save = GIC_PRIO_IRQON;
205 }
206 
207 static inline void start_thread(struct pt_regs *regs, unsigned long pc,
208 				unsigned long sp)
209 {
210 	start_thread_common(regs, pc);
211 	regs->pstate = PSR_MODE_EL0t;
212 
213 	if (arm64_get_ssbd_state() != ARM64_SSBD_FORCE_ENABLE)
214 		regs->pstate |= PSR_SSBS_BIT;
215 
216 	regs->sp = sp;
217 }
218 
219 #ifdef CONFIG_COMPAT
220 static inline void compat_start_thread(struct pt_regs *regs, unsigned long pc,
221 				       unsigned long sp)
222 {
223 	start_thread_common(regs, pc);
224 	regs->pstate = PSR_AA32_MODE_USR;
225 	if (pc & 1)
226 		regs->pstate |= PSR_AA32_T_BIT;
227 
228 #ifdef __AARCH64EB__
229 	regs->pstate |= PSR_AA32_E_BIT;
230 #endif
231 
232 	if (arm64_get_ssbd_state() != ARM64_SSBD_FORCE_ENABLE)
233 		regs->pstate |= PSR_AA32_SSBS_BIT;
234 
235 	regs->compat_sp = sp;
236 }
237 #endif
238 
239 /* Forward declaration, a strange C thing */
240 struct task_struct;
241 
242 /* Free all resources held by a thread. */
243 extern void release_thread(struct task_struct *);
244 
245 unsigned long get_wchan(struct task_struct *p);
246 
247 static inline void cpu_relax(void)
248 {
249 	asm volatile("yield" ::: "memory");
250 }
251 
252 /* Thread switching */
253 extern struct task_struct *cpu_switch_to(struct task_struct *prev,
254 					 struct task_struct *next);
255 
256 #define task_pt_regs(p) \
257 	((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1)
258 
259 #define KSTK_EIP(tsk)	((unsigned long)task_pt_regs(tsk)->pc)
260 #define KSTK_ESP(tsk)	user_stack_pointer(task_pt_regs(tsk))
261 
262 /*
263  * Prefetching support
264  */
265 #define ARCH_HAS_PREFETCH
266 static inline void prefetch(const void *ptr)
267 {
268 	asm volatile("prfm pldl1keep, %a0\n" : : "p" (ptr));
269 }
270 
271 #define ARCH_HAS_PREFETCHW
272 static inline void prefetchw(const void *ptr)
273 {
274 	asm volatile("prfm pstl1keep, %a0\n" : : "p" (ptr));
275 }
276 
277 #define ARCH_HAS_SPINLOCK_PREFETCH
278 static inline void spin_lock_prefetch(const void *ptr)
279 {
280 	asm volatile(ARM64_LSE_ATOMIC_INSN(
281 		     "prfm pstl1strm, %a0",
282 		     "nop") : : "p" (ptr));
283 }
284 
285 #define HAVE_ARCH_PICK_MMAP_LAYOUT
286 
287 #endif
288 
289 extern unsigned long __ro_after_init signal_minsigstksz; /* sigframe size */
290 extern void __init minsigstksz_setup(void);
291 
292 /*
293  * Not at the top of the file due to a direct #include cycle between
294  * <asm/fpsimd.h> and <asm/processor.h>.  Deferring this #include
295  * ensures that contents of processor.h are visible to fpsimd.h even if
296  * processor.h is included first.
297  *
298  * These prctl helpers are the only things in this file that require
299  * fpsimd.h.  The core code expects them to be in this header.
300  */
301 #include <asm/fpsimd.h>
302 
303 /* Userspace interface for PR_SVE_{SET,GET}_VL prctl()s: */
304 #define SVE_SET_VL(arg)	sve_set_current_vl(arg)
305 #define SVE_GET_VL()	sve_get_current_vl()
306 
307 /* PR_PAC_RESET_KEYS prctl */
308 #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
309 
310 /*
311  * For CONFIG_GCC_PLUGIN_STACKLEAK
312  *
313  * These need to be macros because otherwise we get stuck in a nightmare
314  * of header definitions for the use of task_stack_page.
315  */
316 
317 #define current_top_of_stack()							\
318 ({										\
319 	struct stack_info _info;						\
320 	BUG_ON(!on_accessible_stack(current, current_stack_pointer, &_info));	\
321 	_info.high;								\
322 })
323 #define on_thread_stack()	(on_task_stack(current, current_stack_pointer, NULL))
324 
325 #endif /* __ASSEMBLY__ */
326 #endif /* __ASM_PROCESSOR_H */
327