Re: [PATCH] powerpc/interrupt: Don't read MSR from interrupt_exit_kernel_prepare()

On Mon, 05 Jun 2023 10:55:26 +0200, Christophe Leroy wrote:

A disassembly of interrupt_exit_kernel_prepare() shows a useless read
of MSR register. This is shown by r9 being re-used immediately without
doing anything with the value read.

  c000e0e0:       60 00 00 00     nop
  c000e0e4:       7d 3a c2 a6     mfmd_ap r9
  c000e0e8:       7d 20 00 a6     mfmsr   r9
  c000e0ec:       7c 51 13 a6     mtspr   81,r2
  c000e0f0:       81 3f 00 84     lwz     r9,132(r31)
  c000e0f4:       71 29 80 00     andi.   r9,r9,32768

[...]

Applied to powerpc/next.

[1/1] powerpc/interrupt: Don't read MSR from interrupt_exit_kernel_prepare()
      https://git.kernel.org/powerpc/c/0eb089a72fda3f7969e6277804bde75dc1474a14

cheers