diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2021-06-18 01:51:03 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-25 00:06:55 +1000 |
| commit | 59dc5bfca0cb6a29db1a50847684eb5c19f8f400 (patch) | |
| tree | e59ddd65cf780da3df22074afee961dc8503cdc2 /arch/powerpc/kernel/syscalls.c | |
| parent | 1df7d5e4baeac74d14c1bee18b2dff9302b3efbc (diff) | |
powerpc/64s: avoid reloading (H)SRR registers if they are still valid
When an interrupt is taken, the SRR registers are set to return to where
it left off. Unless they are modified in the meantime, or the return
address or MSR are modified, there is no need to reload these registers
when returning from interrupt.
Introduce per-CPU flags that track the validity of SRR and HSRR
registers. These are cleared when returning from interrupt, when
using the registers for something else (e.g., OPAL calls), when
adjusting the return address or MSR of a context, and when context
switching (which changes the return address and MSR).
This improves the performance of interrupt returns.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fold in fixup patch from Nick]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kernel/syscalls.c')
| -rw-r--r-- | arch/powerpc/kernel/syscalls.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c index a552c9e68d7e..bf4ae0f0e36c 100644 --- a/arch/powerpc/kernel/syscalls.c +++ b/arch/powerpc/kernel/syscalls.c @@ -114,7 +114,8 @@ SYSCALL_DEFINE0(switch_endian) { struct thread_info *ti; - current->thread.regs->msr ^= MSR_LE; + regs_set_return_msr(current->thread.regs, + current->thread.regs->msr ^ MSR_LE); /* * Set TIF_RESTOREALL so that r3 isn't clobbered on return to |