[Qemu-devel] [Bug 1723984] Re: ID_MMFR0 has an invalid value on aarch64 cpu (A57, A53)

[Peter Maydell]

Thanks for the update -- I'm going to close this bug. (Incidentally, my
experience with checks of the "insist we're on a known platform with ID
register values we recognize" kind is that they're more trouble than
they're worth, especially if you plan running the software in an
emulator.)


** Changed in: qemu
       Status: New => Invalid

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Title:
  ID_MMFR0 has an invalid value on aarch64 cpu (A57, A53)

Status in QEMU:
  Invalid

Bug description:
  The ID_MMFR0 register, accessed from aarch64 state as an invalid value:
  - ARM ARM v8 documentation (D7.2 General system control registers) described 
bits AuxReg[23:20] to be
    "In ARMv8-A the only permitted value is 0010"
  - Cortex A53 and Cortex A57 TRM describe the value to be 0x10201105, so 
AuxReg[23:20] is 0010 too
  - in QEMU target/arm/cpu64.c, the relevant value is
    cpu->id_mmfr0 = 0x10101105;

  The 1 should be changed to 2.

  Spotted & Tested on the following qemu revision:

  commit 48ae1f60d8c9a770e6da64407984d84e25253c69
  Merge: 78b62d3 b867eaa
  Author: Peter Maydell <address@hidden>
  Date:   Mon Oct 16 14:28:13 2017 +0100

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