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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-04-30 12:39:02 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-05-03 01:20:27 +1000 |
| commit | b86fb88855ea7881314b935df1df6b1ef1bd0c32 (patch) | |
| tree | e2207487af1b98d66207a533c572f5a8c8aa077f /arch/powerpc/kernel/entry_32.S | |
| parent | 40530db7c656119b1671aae5bc27811f66f5f424 (diff) | |
| download | linux-next-b86fb88855ea7881314b935df1df6b1ef1bd0c32.tar.gz | |
powerpc/32: implement fast entry for syscalls on non BOOKE
This patch implements a fast entry for syscalls.
Syscalls don't have to preserve non volatile registers except LR.
This patch then implement a fast entry for syscalls, where
volatile registers get clobbered.
As this entry is dedicated to syscall it always sets MSR_EE
and warns in case MSR_EE was previously off
It also assumes that the call is always from user, system calls are
unexpected from kernel.
The overall series improves null_syscall selftest by 12,5% on an 83xx
and by 17% on a 8xx.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 0c555f9f1543..184cc1de2f37 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -342,6 +342,35 @@ stack_ovf: SYNC RFI +#ifndef CONFIG_BOOKE /* to be removed once BOOKE uses fast syscall entry */ +#ifdef CONFIG_TRACE_IRQFLAGS +trace_syscall_entry_irq_off: + /* + * Syscall shouldn't happen while interrupts are disabled, + * so let's do a warning here. + */ +0: trap + EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING + bl trace_hardirqs_on + + /* Now enable for real */ + LOAD_MSR_KERNEL(r10, MSR_KERNEL | MSR_EE) + mtmsr r10 + + REST_GPR(0, r1) + REST_4GPRS(3, r1) + REST_2GPRS(7, r1) + b DoSyscall +#endif /* CONFIG_TRACE_IRQFLAGS */ + + .globl transfer_to_syscall +transfer_to_syscall: +#ifdef CONFIG_TRACE_IRQFLAGS + andi. r12,r9,MSR_EE + beq- trace_syscall_entry_irq_off +#endif /* CONFIG_TRACE_IRQFLAGS */ +#endif /* !CONFIG_BOOKE */ + /* * Handle a system call. */ @@ -353,9 +382,11 @@ _GLOBAL(DoSyscall) stw r3,ORIG_GPR3(r1) li r12,0 stw r12,RESULT(r1) +#ifdef CONFIG_BOOKE /* to be removed once BOOKE uses fast syscall entry */ lwz r11,_CCR(r1) /* Clear SO bit in CR */ rlwinm r11,r11,0,4,2 stw r11,_CCR(r1) +#endif #ifdef CONFIG_TRACE_IRQFLAGS /* Make sure interrupts are enabled */ mfmsr r11 @@ -1219,6 +1250,7 @@ load_dbcr0: .section .bss .align 4 + .global global_dbcr0 global_dbcr0: .space 8*NR_CPUS .previous |