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/cpufeatures.h> 9 #include <asm/alternative.h> 10 11 #include <linux/kmsan-checks.h> 12 13 /* duplicated to the one in bootmem.h */ 14 extern unsigned long max_pfn; 15 extern unsigned long phys_base; 16 17 extern unsigned long page_offset_base; 18 extern unsigned long vmalloc_base; 19 extern unsigned long vmemmap_base; 20 21 static __always_inline unsigned long __phys_addr_nodebug(unsigned long x) 22 { 23 unsigned long y = x - __START_KERNEL_map; 24 25 /* use the carry flag to determine if x was < __START_KERNEL_map */ 26 x = y + ((x > y) ? phys_base : (__START_KERNEL_map - PAGE_OFFSET)); 27 28 return x; 29 } 30 31 #ifdef CONFIG_DEBUG_VIRTUAL 32 extern unsigned long __phys_addr(unsigned long); 33 extern unsigned long __phys_addr_symbol(unsigned long); 34 #else 35 #define __phys_addr(x) __phys_addr_nodebug(x) 36 #define __phys_addr_symbol(x) \ 37 ((unsigned long)(x) - __START_KERNEL_map + phys_base) 38 #endif 39 40 #define __phys_reloc_hide(x) (x) 41 42 void clear_page_orig(void *page); 43 void clear_page_rep(void *page); 44 void clear_page_erms(void *page); 45 46 static inline void clear_page(void *page) 47 { 48 /* 49 * Clean up KMSAN metadata for the page being cleared. The assembly call 50 * below clobbers @page, so we perform unpoisoning before it. 51 */ 52 kmsan_unpoison_memory(page, PAGE_SIZE); 53 alternative_call_2(clear_page_orig, 54 clear_page_rep, X86_FEATURE_REP_GOOD, 55 clear_page_erms, X86_FEATURE_ERMS, 56 "=D" (page), 57 "D" (page) 58 : "cc", "memory", "rax", "rcx"); 59 } 60 61 void copy_page(void *to, void *from); 62 63 #ifdef CONFIG_X86_5LEVEL 64 /* 65 * User space process size. This is the first address outside the user range. 66 * There are a few constraints that determine this: 67 * 68 * On Intel CPUs, if a SYSCALL instruction is at the highest canonical 69 * address, then that syscall will enter the kernel with a 70 * non-canonical return address, and SYSRET will explode dangerously. 71 * We avoid this particular problem by preventing anything 72 * from being mapped at the maximum canonical address. 73 * 74 * On AMD CPUs in the Ryzen family, there's a nasty bug in which the 75 * CPUs malfunction if they execute code from the highest canonical page. 76 * They'll speculate right off the end of the canonical space, and 77 * bad things happen. This is worked around in the same way as the 78 * Intel problem. 79 * 80 * With page table isolation enabled, we map the LDT in ... [stay tuned] 81 */ 82 static __always_inline unsigned long task_size_max(void) 83 { 84 unsigned long ret; 85 86 alternative_io("movq %[small],%0","movq %[large],%0", 87 X86_FEATURE_LA57, 88 "=r" (ret), 89 [small] "i" ((1ul << 47)-PAGE_SIZE), 90 [large] "i" ((1ul << 56)-PAGE_SIZE)); 91 92 return ret; 93 } 94 #endif /* CONFIG_X86_5LEVEL */ 95 96 #endif /* !__ASSEMBLY__ */ 97 98 #ifdef CONFIG_X86_VSYSCALL_EMULATION 99 # define __HAVE_ARCH_GATE_AREA 1 100 #endif 101 102 #endif /* _ASM_X86_PAGE_64_H */ 103