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Linux kernel mirror (for testing)
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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 */
11extern unsigned long max_pfn;
12extern unsigned long phys_base;
13
14extern unsigned long page_offset_base;
15extern unsigned long vmalloc_base;
16extern unsigned long vmemmap_base;
17
18static 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
29extern unsigned long __phys_addr(unsigned long);
30extern 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
43void clear_page_orig(void *page);
44void clear_page_rep(void *page);
45void clear_page_erms(void *page);
46
47static 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
57void 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 */
78static __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 */