1 // SPDX-License-Identifier: GPL-2.0-only 2 3 #define pr_fmt(fmt) "efi: " fmt 4 5 #include <linux/module.h> 6 #include <linux/init.h> 7 #include <linux/efi.h> 8 #include <linux/libfdt.h> 9 #include <linux/of_fdt.h> 10 11 #include <asm/unaligned.h> 12 13 enum { 14 SYSTAB, 15 MMBASE, 16 MMSIZE, 17 DCSIZE, 18 DCVERS, 19 20 PARAMCOUNT 21 }; 22 23 static __initconst const char name[][22] = { 24 [SYSTAB] = "System Table ", 25 [MMBASE] = "MemMap Address ", 26 [MMSIZE] = "MemMap Size ", 27 [DCSIZE] = "MemMap Desc. Size ", 28 [DCVERS] = "MemMap Desc. Version ", 29 }; 30 31 static __initconst const struct { 32 const char path[17]; 33 const char params[PARAMCOUNT][26]; 34 } dt_params[] = { 35 { 36 #ifdef CONFIG_XEN // <-------17------> 37 .path = "/hypervisor/uefi", 38 .params = { 39 [SYSTAB] = "xen,uefi-system-table", 40 [MMBASE] = "xen,uefi-mmap-start", 41 [MMSIZE] = "xen,uefi-mmap-size", 42 [DCSIZE] = "xen,uefi-mmap-desc-size", 43 [DCVERS] = "xen,uefi-mmap-desc-ver", 44 } 45 }, { 46 #endif 47 .path = "/chosen", 48 .params = { // <-----------26-----------> 49 [SYSTAB] = "linux,uefi-system-table", 50 [MMBASE] = "linux,uefi-mmap-start", 51 [MMSIZE] = "linux,uefi-mmap-size", 52 [DCSIZE] = "linux,uefi-mmap-desc-size", 53 [DCVERS] = "linux,uefi-mmap-desc-ver", 54 } 55 } 56 }; 57 58 static int __init efi_get_fdt_prop(const void *fdt, int node, const char *pname, 59 const char *rname, void *var, int size) 60 { 61 const void *prop; 62 int len; 63 u64 val; 64 65 prop = fdt_getprop(fdt, node, pname, &len); 66 if (!prop) 67 return 1; 68 69 val = (len == 4) ? (u64)be32_to_cpup(prop) : get_unaligned_be64(prop); 70 71 if (size == 8) 72 *(u64 *)var = val; 73 else 74 *(u32 *)var = (val < U32_MAX) ? val : U32_MAX; // saturate 75 76 if (efi_enabled(EFI_DBG)) 77 pr_info(" %s: 0x%0*llx\n", rname, size * 2, val); 78 79 return 0; 80 } 81 82 u64 __init efi_get_fdt_params(struct efi_memory_map_data *mm) 83 { 84 const void *fdt = initial_boot_params; 85 unsigned long systab; 86 int i, j, node; 87 struct { 88 void *var; 89 int size; 90 } target[] = { 91 [SYSTAB] = { &systab, sizeof(systab) }, 92 [MMBASE] = { &mm->phys_map, sizeof(mm->phys_map) }, 93 [MMSIZE] = { &mm->size, sizeof(mm->size) }, 94 [DCSIZE] = { &mm->desc_size, sizeof(mm->desc_size) }, 95 [DCVERS] = { &mm->desc_version, sizeof(mm->desc_version) }, 96 }; 97 98 BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(name)); 99 BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(dt_params[0].params)); 100 101 for (i = 0; i < ARRAY_SIZE(dt_params); i++) { 102 node = fdt_path_offset(fdt, dt_params[i].path); 103 if (node < 0) 104 continue; 105 106 if (efi_enabled(EFI_DBG)) 107 pr_info("Getting UEFI parameters from %s in DT:\n", 108 dt_params[i].path); 109 110 for (j = 0; j < ARRAY_SIZE(target); j++) { 111 const char *pname = dt_params[i].params[j]; 112 113 if (!efi_get_fdt_prop(fdt, node, pname, name[j], 114 target[j].var, target[j].size)) 115 continue; 116 if (!j) 117 goto notfound; 118 pr_err("Can't find property '%s' in DT!\n", pname); 119 return 0; 120 } 121 return systab; 122 } 123 notfound: 124 pr_info("UEFI not found.\n"); 125 return 0; 126 } 127