git.saurik.com Git - apple/xnu.git/blob - bsd/dev/arm/kern

1 /*

3 */

4 /*

6 *

7 * File: next/kern_machdep.c

8 * Author: John Seamons

9 *

10 * Machine-specific kernel routines.

11 */

13 #include <sys/types.h>

14 #include <mach/machine.h>

15 #include <kern/cpu_number.h>

16 #include <libkern/libkern.h>

17 #include <machine/exec.h>

18 #include <pexpert/arm64/board_config.h>

20 #if __arm64__

 static cpu_subtype_t cpu_subtype32(void);

22 #endif /* __arm64__ */

24 #if __arm64__

25 /*

26 * When an arm64 CPU is executing an arm32 binary, we need to map from the

27 * host's 64-bit subtype to the appropriate 32-bit subtype.

28 */

29 static cpu_subtype_t

30 cpu_subtype32()

31 {

32 switch (cpu_subtype()) {

33 case CPU_SUBTYPE_ARM64_V8:

34 return CPU_SUBTYPE_ARM_V8;

35 default:

36 return 0;

37 }

38 }

40 static int

41 grade_arm64e_binary(cpu_subtype_t execfeatures)

42 {

43 #if XNU_TARGET_OS_IOS

44 /*

45 * iOS 13 toolchains produced unversioned arm64e slices which are not

46 * ABI compatible with this release.

47 */

         if ((execfeatures & CPU_SUBTYPE_PTRAUTH_ABI) == 0) {

49 #if DEBUG || DEVELOPMENT

                 printf("%s: arm64e prerelease ABI cannot be used with this kernel\n", __func__);

51 #endif /* DEBUG || DEVELOPMENT */

52 return 0;

53 }

54 #endif /* XNU_TARGET_OS_IOS */

56 /* The current ABI version is preferred over arm64 */

         if (CPU_SUBTYPE_ARM64_PTR_AUTH_VERSION(execfeatures) ==

58 CPU_SUBTYPE_ARM64_PTR_AUTH_CURRENT_VERSION) {

59 return 12;

60 }

62 /* Future ABIs are allowed, but exec_mach_imgact will treat it like an arm64 slice */

63 return 11;

64 }

65 #endif /* __arm64__ */

67 /**********************************************************************

68 * Routine: grade_binary()

69 *

70 * Function: Return a relative preference for exectypes and

71 * execsubtypes in fat executable files. The higher the

72 * grade, the higher the preference. A grade of 0 means

73 * not acceptable.

74 **********************************************************************/

75 int

 grade_binary(cpu_type_t exectype, cpu_subtype_t execsubtype, cpu_subtype_t execfeatures __unused, bool allow_simulator_binary __unused)

77 {

78 #if __arm64__

79 cpu_subtype_t hostsubtype =

             (exectype & CPU_ARCH_ABI64) ? cpu_subtype() : cpu_subtype32();

81 #else

82 cpu_subtype_t hostsubtype = cpu_subtype();

83 #endif /* __arm64__ */

85 switch (exectype) {

86 #if __arm64__

87 case CPU_TYPE_ARM64:

88 switch (hostsubtype) {

89 case CPU_SUBTYPE_ARM64_V8:

90 switch (execsubtype) {

91 case CPU_SUBTYPE_ARM64_V8:

92 return 10;

93 case CPU_SUBTYPE_ARM64_ALL:

94 return 9;

95 }

96 break;

98 case CPU_SUBTYPE_ARM64E:

99 switch (execsubtype) {

100 case CPU_SUBTYPE_ARM64E:

101 return grade_arm64e_binary(execfeatures);

102 case CPU_SUBTYPE_ARM64_V8:

103 return 10;

104 case CPU_SUBTYPE_ARM64_ALL:

105 return 9;

106 }

107 } /* switch (hostsubtype) */

108 break;

109

110 #else /* __arm64__ */

111

112 case CPU_TYPE_ARM:

113 switch (hostsubtype) {

114 /*

115 * For 32-bit ARMv8, try the ARMv8 slice before falling back to Swift.

116 */

117 case CPU_SUBTYPE_ARM_V8:

118 switch (execsubtype) {

119 case CPU_SUBTYPE_ARM_V8:

120 return 7;

121 }

122 goto v7s;

123

124 /*

125 * For Swift and later, we prefer to run a swift slice, but fall back

126 * to v7 as Cortex A9 errata should not apply

127 */

128 v7s:

129 case CPU_SUBTYPE_ARM_V7S:

130 switch (execsubtype) {

131 case CPU_SUBTYPE_ARM_V7S:

132 return 6;

133 }

134 goto v7;

135

136 /*

137 * For Cortex A7, accept v7k only due to differing ABI

138 */

139 case CPU_SUBTYPE_ARM_V7K:

140 switch (execsubtype) {

141 case CPU_SUBTYPE_ARM_V7K:

142 return 6;

143 }

144 break;

145

146 /*

147 * For Cortex A9, we prefer the A9 slice, but will run v7 albeit

148 * under the risk of hitting the NEON load/store errata

149 */

150 case CPU_SUBTYPE_ARM_V7F:

151 switch (execsubtype) {

152 case CPU_SUBTYPE_ARM_V7F:

153 return 6;

154 }

155 goto v7;

156

157 v7:

158 case CPU_SUBTYPE_ARM_V7:

159 switch (execsubtype) {

160 case CPU_SUBTYPE_ARM_V7:

161 return 5;

162 }

163 // fall through...

164

165 case CPU_SUBTYPE_ARM_V6:

166 switch (execsubtype) {

167 case CPU_SUBTYPE_ARM_V6:

168 return 4;

169 }

170 // fall through...

171

172 case CPU_SUBTYPE_ARM_V5TEJ:

173 switch (execsubtype) {

174 case CPU_SUBTYPE_ARM_V5TEJ:

175 return 3;

176 }

177 // fall through

178

179 case CPU_SUBTYPE_ARM_V4T:

180 switch (execsubtype) {

181 case CPU_SUBTYPE_ARM_V4T:

182 return 2;

183 case CPU_SUBTYPE_ARM_ALL:

184 return 1;

185 }

186 break;

187

188 case CPU_SUBTYPE_ARM_XSCALE:

189 switch (execsubtype) {

190 case CPU_SUBTYPE_ARM_XSCALE:

191 return 4;

192 case CPU_SUBTYPE_ARM_V5TEJ:

193 return 3;

194 case CPU_SUBTYPE_ARM_V4T:

195 return 2;

196 case CPU_SUBTYPE_ARM_ALL:

197 return 1;

198 }

199 break;

200 }

201 #endif /* __arm64__ */

202 }

203

204 return 0;

205 }