ACK: [SRU][Focal][PATCH] arm64/crash_core: Export TCR_EL1.T1SZ in vmcoreinfo

[Guilherme G. Piccoli]

On 15/04/2021 09:10, Ioanna Alifieraki wrote:
> From: Bhupesh Sharma <bhsharma at redhat.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1919275
> 
> TCR_EL1.TxSZ, which controls the VA space size, is configured by a
> single kernel image to support either 48-bit or 52-bit VA space.
> 
> If the ARMv8.2-LVA optional feature is present and we are running
> with a 64KB page size, then it is possible to use 52-bits of address
> space for both userspace and kernel addresses. However, any kernel
> binary that supports 52-bit must also be able to fall back to 48-bit
> at early boot time if the hardware feature is not present.
> 
> Since TCR_EL1.T1SZ indicates the size of the memory region addressed by
> TTBR1_EL1, export the same in vmcoreinfo. User-space utilities like
> makedumpfile and crash-utility need to read this value from vmcoreinfo
> for determining if a virtual address lies in the linear map range.
> 
> While at it also add documentation for TCR_EL1.T1SZ variable being
> added to vmcoreinfo.
> 
> It indicates the size offset of the memory region addressed by
> TTBR1_EL1.
> 
> Signed-off-by: Bhupesh Sharma <bhsharma at redhat.com>
> Tested-by: John Donnelly <john.p.donnelly at oracle.com>
> Tested-by: Kamlakant Patel <kamlakantp at marvell.com>
> Tested-by: Amit Daniel Kachhap <amit.kachhap at arm.com>
> Reviewed-by: James Morse <james.morse at arm.com>
> Reviewed-by: Amit Daniel Kachhap <amit.kachhap at arm.com>
> Cc: James Morse <james.morse at arm.com>
> Cc: Mark Rutland <mark.rutland at arm.com>
> Cc: Will Deacon <will at kernel.org>
> Cc: Steve Capper <steve.capper at arm.com>
> Cc: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> Cc: Dave Anderson <anderson at redhat.com>
> Cc: Kazuhito Hagio <k-hagio at ab.jp.nec.com>
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-kernel at vger.kernel.org
> Cc: kexec at lists.infradead.org
> Link: https://lore.kernel.org/r/1589395957-24628-3-git-send-email-bhsharma@redhat.com
> [catalin.marinas at arm.com: removed vabits_actual from the commit log]
> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> (backported from commit bbdbc11804ff0b4130e7550113b452e96a74d16e)
> [hook 1: resolve conflict in documentation]
> Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki at canonical.com>

Thanks Jo, I remember this from the upstream discussion! LGTM:
Acked-by: Guilherme G. Piccoli <gpiccoli at canonical.com>