1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_PAGE_64_H
3 #define _ASM_X86_PAGE_64_H
4 
5 #include <asm/page_64_types.h>
6 
7 #ifndef __ASSEMBLY__
8 #include <asm/alternative.h>
9 
10 /* duplicated to the one in bootmem.h */
11 extern unsigned long max_pfn;
12 extern unsigned long phys_base;
13 
14 extern unsigned long page_offset_base;
15 extern unsigned long vmalloc_base;
16 extern unsigned long vmemmap_base;
17 
__phys_addr_nodebug(unsigned long x)18 static inline unsigned long __phys_addr_nodebug(unsigned long x)
19 {
20 	unsigned long y = x - __START_KERNEL_map;
21 
22 	/* use the carry flag to determine if x was < __START_KERNEL_map */
23 	x = y + ((x > y) ? phys_base : (__START_KERNEL_map - PAGE_OFFSET));
24 
25 	return x;
26 }
27 
28 #ifdef CONFIG_DEBUG_VIRTUAL
29 extern unsigned long __phys_addr(unsigned long);
30 extern unsigned long __phys_addr_symbol(unsigned long);
31 #else
32 #define __phys_addr(x)		__phys_addr_nodebug(x)
33 #define __phys_addr_symbol(x) \
34 	((unsigned long)(x) - __START_KERNEL_map + phys_base)
35 #endif
36 
37 #define __phys_reloc_hide(x)	(x)
38 
39 #ifdef CONFIG_FLATMEM
40 #define pfn_valid(pfn)          ((pfn) < max_pfn)
41 #endif
42 
43 void clear_page_orig(void *page);
44 void clear_page_rep(void *page);
45 void clear_page_erms(void *page);
46 
clear_page(void * page)47 static inline void clear_page(void *page)
48 {
49 	alternative_call_2(clear_page_orig,
50 			   clear_page_rep, X86_FEATURE_REP_GOOD,
51 			   clear_page_erms, X86_FEATURE_ERMS,
52 			   "=D" (page),
53 			   "0" (page)
54 			   : "cc", "memory", "rax", "rcx");
55 }
56 
57 void copy_page(void *to, void *from);
58 
59 #ifdef CONFIG_X86_5LEVEL
60 /*
61  * User space process size.  This is the first address outside the user range.
62  * There are a few constraints that determine this:
63  *
64  * On Intel CPUs, if a SYSCALL instruction is at the highest canonical
65  * address, then that syscall will enter the kernel with a
66  * non-canonical return address, and SYSRET will explode dangerously.
67  * We avoid this particular problem by preventing anything
68  * from being mapped at the maximum canonical address.
69  *
70  * On AMD CPUs in the Ryzen family, there's a nasty bug in which the
71  * CPUs malfunction if they execute code from the highest canonical page.
72  * They'll speculate right off the end of the canonical space, and
73  * bad things happen.  This is worked around in the same way as the
74  * Intel problem.
75  *
76  * With page table isolation enabled, we map the LDT in ... [stay tuned]
77  */
task_size_max(void)78 static __always_inline unsigned long task_size_max(void)
79 {
80 	unsigned long ret;
81 
82 	alternative_io("movq %[small],%0","movq %[large],%0",
83 			X86_FEATURE_LA57,
84 			"=r" (ret),
85 			[small] "i" ((1ul << 47)-PAGE_SIZE),
86 			[large] "i" ((1ul << 56)-PAGE_SIZE));
87 
88 	return ret;
89 }
90 #endif	/* CONFIG_X86_5LEVEL */
91 
92 #endif	/* !__ASSEMBLY__ */
93 
94 #ifdef CONFIG_X86_VSYSCALL_EMULATION
95 # define __HAVE_ARCH_GATE_AREA 1
96 #endif
97 
98 #endif /* _ASM_X86_PAGE_64_H */
99