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 __ASSEMBLER__
8#include <asm/cpufeatures.h>
9#include <asm/alternative.h>
10
11#include <linux/kmsan-checks.h>
12#include <linux/mmdebug.h>
13
14/* duplicated to the one in bootmem.h */
15extern unsigned long max_pfn;
16extern unsigned long phys_base;
17
18extern unsigned long page_offset_base;
19extern unsigned long vmalloc_base;
20extern unsigned long vmemmap_base;
21extern unsigned long direct_map_physmem_end;
22
23static __always_inline unsigned long __phys_addr_nodebug(unsigned long x)
24{
25 unsigned long y = x - __START_KERNEL_map;
26
27 /* use the carry flag to determine if x was < __START_KERNEL_map */
28 x = y + ((x > y) ? phys_base : (__START_KERNEL_map - PAGE_OFFSET));
29
30 return x;
31}
32
33#ifdef CONFIG_DEBUG_VIRTUAL
34extern unsigned long __phys_addr(unsigned long);
35#else
36#define __phys_addr(x) __phys_addr_nodebug(x)
37#endif
38
39static inline unsigned long __phys_addr_symbol(unsigned long x)
40{
41 unsigned long y = x - __START_KERNEL_map;
42
43 /* only check upper bounds since lower bounds will trigger carry */
44 VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);
45
46 return y + phys_base;
47}
48
49#define __phys_reloc_hide(x) (x)
50
51void clear_page_orig(void *page);
52void clear_page_rep(void *page);
53void clear_page_erms(void *page);
54KCFI_REFERENCE(clear_page_orig);
55KCFI_REFERENCE(clear_page_rep);
56KCFI_REFERENCE(clear_page_erms);
57
58static inline void clear_page(void *page)
59{
60 /*
61 * Clean up KMSAN metadata for the page being cleared. The assembly call
62 * below clobbers @page, so we perform unpoisoning before it.
63 */
64 kmsan_unpoison_memory(address: page, PAGE_SIZE);
65 alternative_call_2(clear_page_orig,
66 clear_page_rep, X86_FEATURE_REP_GOOD,
67 clear_page_erms, X86_FEATURE_ERMS,
68 "=D" (page),
69 "D" (page),
70 "cc", "memory", "rax", "rcx");
71}
72
73void copy_page(void *to, void *from);
74KCFI_REFERENCE(copy_page);
75
76/*
77 * User space process size. This is the first address outside the user range.
78 * There are a few constraints that determine this:
79 *
80 * On Intel CPUs, if a SYSCALL instruction is at the highest canonical
81 * address, then that syscall will enter the kernel with a
82 * non-canonical return address, and SYSRET will explode dangerously.
83 * We avoid this particular problem by preventing anything
84 * from being mapped at the maximum canonical address.
85 *
86 * On AMD CPUs in the Ryzen family, there's a nasty bug in which the
87 * CPUs malfunction if they execute code from the highest canonical page.
88 * They'll speculate right off the end of the canonical space, and
89 * bad things happen. This is worked around in the same way as the
90 * Intel problem.
91 *
92 * With page table isolation enabled, we map the LDT in ... [stay tuned]
93 */
94static __always_inline unsigned long task_size_max(void)
95{
96 unsigned long ret;
97
98 alternative_io("movq %[small],%0","movq %[large],%0",
99 X86_FEATURE_LA57,
100 "=r" (ret),
101 [small] "i" ((1ul << 47)-PAGE_SIZE),
102 [large] "i" ((1ul << 56)-PAGE_SIZE));
103
104 return ret;
105}
106
107#endif /* !__ASSEMBLER__ */
108
109#ifdef CONFIG_X86_VSYSCALL_EMULATION
110# define __HAVE_ARCH_GATE_AREA 1
111#endif
112
113#endif /* _ASM_X86_PAGE_64_H */
114

source code of linux/arch/x86/include/asm/page_64.h