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2b641211c5
The AArch64 TCR_ELx register is a 64-bit register, and many newer architecture features use bits in the upper half. So far U-Boot was igorant of those bits, trying to leave them alone. However, in an effort to set bit 31 to 1, it failed doing so, because the compiler sign-extended "1 << 31", so that all bits[63:31] got set. Older ARMv8.0 cores don't define anything dangerous up there, but newer architecture revisions do, and setting all those bits will end badly: ================= $ qemu-system-aarch64 -cpu max .... U-Boot 2022.07-rc1 (May 09 2022 - 15:21:00 +0100) DRAM: 1.5 GiB ================= (hangs here) Defining TCR_ELx_RSVD to "1U << 31" avoids the sign-extension, so all upper bits stay at a safe 0 value. This means no more surprises when U-Boot runs on a more capable CPU core. Reported-by: Balaji Anandapadmanaban <Balaji.Anandapadmanaban@arm.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Peng Fan <peng.fan@nxp.com> Tested-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Peter Collingbourne <pcc@google.com> |
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