Re: [PATCH v4 00/17] powerpc/64: fast interrupt exits

On Fri, 18 Jun 2021 01:50:59 +1000, Nicholas Piggin wrote:

This series attempts to improve the speed of interrupts and system calls
in three major ways.

Firstly, the SRR/HSRR registers do not need to be reloaded if they were
clobbered for the duration of the interrupt and the return NIP and MSR
did not changed. 64e does not implement this part, but it could quite
easily.

[...]

Patches 1-4, and 6-17 applied to powerpc/next.

[01/17] powerpc/interrupt: Fix CONFIG ifdef typo
        https://git.kernel.org/powerpc/c/9a3ed7adcabce24a85fbe05f54e762b18756ec22
[02/17] powerpc: remove interrupt exit helpers unused argument
        https://git.kernel.org/powerpc/c/bf9155f1970c4dbf9ec6b87d3688433bd494a4e1
[03/17] powerpc/64s: introduce different functions to return from SRR vs HSRR interrupts
        https://git.kernel.org/powerpc/c/1df7d5e4baeac74d14c1bee18b2dff9302b3efbc
[04/17] powerpc/64s: avoid reloading (H)SRR registers if they are still valid
        https://git.kernel.org/powerpc/c/59dc5bfca0cb6a29db1a50847684eb5c19f8f400
[06/17] powerpc/64: move interrupt return asm to interrupt_64.S
        https://git.kernel.org/powerpc/c/e754f4d13e3919aafa485657599907aa63b9a40c
[07/17] powerpc/64s: system call avoid setting MSR[RI] until we set MSR[EE]
        https://git.kernel.org/powerpc/c/dd152f70bdc1b91445b10c65ac874b90c93fb3b5
[08/17] powerpc/64s: save one more register in the masked interrupt handler
        https://git.kernel.org/powerpc/c/63e40806eea984f770c992120bbfd71b589ea580
[09/17] powerpc/64: allow alternate return locations for soft-masked interrupts
        https://git.kernel.org/powerpc/c/f23699c93becd746295aaa506537882a46a62219
[10/17] powerpc/64: interrupt soft-enable race fix
        https://git.kernel.org/powerpc/c/862fa563524b9f92d7e89fe332732bd3421772db
[11/17] powerpc/64: treat low kernel text as irqs soft-masked
        https://git.kernel.org/powerpc/c/9d1988ca87dd90ecf80a0601c7fd13071fbb1a83
[12/17] powerpc/64: use interrupt restart table to speed up return from interrupt
        https://git.kernel.org/powerpc/c/13799748b957bc5659f97c036224b0f4b42172e2
[13/17] powerpc/interrupt: Rename and lightly change syscall_exit_prepare_main()
        https://git.kernel.org/powerpc/c/f84aa284947f325c5697d35b92abd2047224f24b
[14/17] powerpc/interrupt: Refactor interrupt_exit_user_prepare()
        https://git.kernel.org/powerpc/c/a214ee8802adb864d175ea6ca4176223bcc11d2b
[15/17] powerpc/interrupt: Interchange prep_irq_for_{kernel_enabled/user}_exit()
        https://git.kernel.org/powerpc/c/99f98f849cf13e5fac532979ccdb77dff07665db
[16/17] powerpc/interrupt: Refactor prep_irq_for_{user/kernel_enabled}_exit()
        https://git.kernel.org/powerpc/c/61eece2d1707796fd45225ea3d20e9289251311c
[17/17] powerpc/interrupt: Remove prep_irq_for_user_exit()
        https://git.kernel.org/powerpc/c/ae58b1c645895c28ca155843db6788d57ea99e11

cheers