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/lib/sstep.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/lib/sstep.c')
| -rw-r--r-- | arch/powerpc/lib/sstep.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index aee42bcc775b..d8d5f901cee1 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -3225,7 +3225,7 @@ void emulate_update_regs(struct pt_regs *regs, struct instruction_op *op) default: WARN_ON_ONCE(1); } - regs->nip = next_pc; + regs_set_return_ip(regs, next_pc); } NOKPROBE_SYMBOL(emulate_update_regs); @@ -3563,7 +3563,7 @@ int emulate_step(struct pt_regs *regs, struct ppc_inst instr) /* can't step mtmsr[d] that would clear MSR_RI */ return -1; /* here op.val is the mask of bits to change */ - regs->msr = (regs->msr & ~op.val) | (val & op.val); + regs_set_return_msr(regs, (regs->msr & ~op.val) | (val & op.val)); goto instr_done; #ifdef CONFIG_PPC64 @@ -3576,7 +3576,7 @@ int emulate_step(struct pt_regs *regs, struct ppc_inst instr) if (IS_ENABLED(CONFIG_PPC_FAST_ENDIAN_SWITCH) && cpu_has_feature(CPU_FTR_REAL_LE) && regs->gpr[0] == 0x1ebe) { - regs->msr ^= MSR_LE; + regs_set_return_msr(regs, regs->msr ^ MSR_LE); goto instr_done; } regs->gpr[9] = regs->gpr[13]; @@ -3584,8 +3584,8 @@ int emulate_step(struct pt_regs *regs, struct ppc_inst instr) regs->gpr[11] = regs->nip + 4; regs->gpr[12] = regs->msr & MSR_MASK; regs->gpr[13] = (unsigned long) get_paca(); - regs->nip = (unsigned long) &system_call_common; - regs->msr = MSR_KERNEL; + regs_set_return_ip(regs, (unsigned long) &system_call_common); + regs_set_return_msr(regs, MSR_KERNEL); return 1; #ifdef CONFIG_PPC_BOOK3S_64 @@ -3595,8 +3595,8 @@ int emulate_step(struct pt_regs *regs, struct ppc_inst instr) regs->gpr[11] = regs->nip + 4; regs->gpr[12] = regs->msr & MSR_MASK; regs->gpr[13] = (unsigned long) get_paca(); - regs->nip = (unsigned long) &system_call_vectored_emulate; - regs->msr = MSR_KERNEL; + regs_set_return_ip(regs, (unsigned long) &system_call_vectored_emulate); + regs_set_return_msr(regs, MSR_KERNEL); return 1; #endif @@ -3607,7 +3607,8 @@ int emulate_step(struct pt_regs *regs, struct ppc_inst instr) return 0; instr_done: - regs->nip = truncate_if_32bit(regs->msr, regs->nip + GETLENGTH(op.type)); + regs_set_return_ip(regs, + truncate_if_32bit(regs->msr, regs->nip + GETLENGTH(op.type))); return 1; } NOKPROBE_SYMBOL(emulate_step); |