[Qemu-commits] [qemu/qemu] 4553e1: target-sparc: fix ldstub sign-extension bug

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: 4553e10360a0713e31647220ed396942f9a6fca0
      
https://github.com/qemu/qemu/commit/4553e10360a0713e31647220ed396942f9a6fca0
  Author: Mark Cave-Ayland <address@hidden>
  Date:   2016-04-11 (Mon, 11 Apr 2016)

  Changed paths:
    M target-sparc/translate.c

  Log Message:
  -----------
  target-sparc: fix ldstub sign-extension bug

ldstub [addr], reg incorrectly reads a signed byte from memory which causes
problems in the 32-bit Solaris mutex code. Here the byte value being read is
0xff which is incorrectly sign-extended to 0xffffffff before being written back
to the target register causing lock detection to behave incorrectly.

This fixes the intermittent hangs and MUTEX_HELD warnings issued to the
console when running 32-bit Solaris images under qemu-system-sparc.

With thanks to Joseph Dery for providing a condensed test image to consistently
reproduce the problem on demand, and Martin Husemann for allowing me access to
real hardware for comparison.

Signed-off-by: Mark Cave-Ayland <address@hidden>
Reviewed-By: Artyom Tarasenko <address@hidden>
Signed-off-by: Mark Cave-Ayland <address@hidden>


  Commit: 4e71220387e88a22e03e47cabd5aafe105147746
      
https://github.com/qemu/qemu/commit/4e71220387e88a22e03e47cabd5aafe105147746
  Author: Peter Maydell <address@hidden>
  Date:   2016-04-11 (Mon, 11 Apr 2016)

  Changed paths:
    M target-sparc/translate.c

  Log Message:
  -----------
  Merge remote-tracking branch 'remotes/mcayland/tags/qemu-sparc-signed' into 
staging

qemu-sparc update

# gpg: Signature made Mon 11 Apr 2016 16:30:02 BST using RSA key ID AE0F321F
# gpg: Good signature from "Mark Cave-Ayland <address@hidden>"

* remotes/mcayland/tags/qemu-sparc-signed:
  target-sparc: fix ldstub sign-extension bug

Signed-off-by: Peter Maydell <address@hidden>


Compare: https://github.com/qemu/qemu/compare/dc1ffa66619b...4e71220387e8