diff options
Diffstat (limited to 'ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S')
| -rw-r--r-- | ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S b/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S index 1ef2f61f59..b7173e00b0 100644 --- a/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S +++ b/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S @@ -196,4 +196,21 @@ ASM_FUNC(ArmWriteSctlr) 3:msr sctlr_el3, x0
4:ret
+ASM_FUNC(ArmGetPhysicalAddressBits)
+ mrs x0, id_aa64mmfr0_el1
+ adr x1, .LPARanges
+ and x0, x0, #0xf
+ ldrb w0, [x1, x0]
+ ret
+
+//
+// Bits 0..3 of the AA64MFR0_EL1 system register encode the size of the
+// physical address space support on this CPU:
+// 0 == 32 bits, 1 == 36 bits, etc etc
+// 7 and up are reserved
+//
+.LPARanges:
+ .byte 32, 36, 40, 42, 44, 48, 52, 0
+ .byte 0, 0, 0, 0, 0, 0, 0, 0
+
ASM_FUNCTION_REMOVE_IF_UNREFERENCED
|