diff options
Diffstat (limited to 'system/arm/aarch64_bootloader')
| -rw-r--r-- | system/arm/aarch64_bootloader/boot.S | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/system/arm/aarch64_bootloader/boot.S b/system/arm/aarch64_bootloader/boot.S index 78d9710d4..933d7ee8a 100644 --- a/system/arm/aarch64_bootloader/boot.S +++ b/system/arm/aarch64_bootloader/boot.S @@ -34,8 +34,12 @@ _start: * registers. */ mrs x0, mpidr_el1 - tst x0, #15 - b.ne 1f // secondary CPU + // ARM MPIDR_EL1 bytes: Aff3 (AArch64), Stuff, Aff2, Aff1, Aff0 + // Test the the MPIDR_EL1 register against 0xff00ffffff to + // extract the primary CPU. + ldr x1, =0xff00ffffff + tst x0, x1 // check for cpuid==zero + b.ne 1f // secondary CPU ldr x1, =GIC_DIST_BASE // GICD_CTLR mov w0, #3 // EnableGrp0 | EnableGrp1 @@ -77,8 +81,13 @@ start_ns: mov x3, xzr mrs x4, mpidr_el1 - tst x4, #15 - b.eq 2f + // ARM MPIDR_EL1 bytes: Aff3 (AArch64), Stuff, Aff2, Aff1, Aff0 + // Test the the MPIDR_EL1 register against 0xff00ffffff to + // extract the primary CPU. + ldr x1, =0xff00ffffff + tst x4, x1 // check for cpuid==zero + mov x1, xzr // load previous 'xzr' value back to x1 + b.eq 2f // secondary CPU /* * Secondary CPUs |