[PATCH] armv8: Fix TCR 64-bit writes

[Tom Rini]

On Mon, May 09, 2022 at 05:08:49PM +0100, Andre Przywara wrote:

> 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 at arm.com>
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> Reviewed-by: Peng Fan <peng.fan at nxp.com>
> Tested-by: Peter Collingbourne <pcc at google.com>
> Reviewed-by: Peter Collingbourne <pcc at google.com>

Applied to u-boot/master, thanks!

-- 
Tom
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