| Message ID | ba23b45ec5e4a0acb040cacc48949f7bc984b0ee.1549630193.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc/32: Implement fast syscall entry | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | fail | total: 54 errors, 2 warnings, 3 checks, 179 lines checked |
Le 08/02/2019 à 13:52, Christophe Leroy a écrit : > 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> The following addition is required to avoid build failure on 40x as global_dbcr0 is going to be accessed from head_40x.S diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 85f1fc88c237..987f0fafc999 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -1247,6 +1247,7 @@ load_dbcr0: .section .bss .align 4 + .global global_dbcr0 global_dbcr0: .space 8*NR_CPUS .previous Christophe > --- > arch/powerpc/kernel/entry_32.S | 42 +++++++++++++++++++++ > arch/powerpc/kernel/head_32.S | 3 +- > arch/powerpc/kernel/head_32.h | 85 ++++++++++++++++++++++++++++++++++++++++-- > arch/powerpc/kernel/head_40x.S | 3 +- > arch/powerpc/kernel/head_8xx.S | 3 +- > 5 files changed, 126 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S > index 1e11528d45ae..137bd2103051 100644 > --- a/arch/powerpc/kernel/entry_32.S > +++ b/arch/powerpc/kernel/entry_32.S > @@ -335,6 +335,46 @@ 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: > + /* > + * The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1. > + * If from user mode there is only one stack frame on the stack, and > + * accessing CALLER_ADDR1 will cause oops. So we need create a dummy > + * stack frame to make trace_hardirqs_on happy. > + * > + */ > + stwu r1,-32(r1) > + > + /* > + * 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 > + > + addi r1,r1,32 > + > + /* 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. > */ > @@ -346,9 +386,11 @@ _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 */ > diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S > index 3a1df9edf6da..7576e1374a69 100644 > --- a/arch/powerpc/kernel/head_32.S > +++ b/arch/powerpc/kernel/head_32.S > @@ -368,8 +368,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE) > . = 0xc00 > DO_KVM 0xc00 > SystemCall: > - EXCEPTION_PROLOG > - EXC_XFER_SYS(0xc00, DoSyscall) > + SYSCALL_ENTRY 0xc00 > > /* Single step - not used on 601 */ > EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD) > diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h > index 14cb0af2f494..4a692553651f 100644 > --- a/arch/powerpc/kernel/head_32.h > +++ b/arch/powerpc/kernel/head_32.h > @@ -73,6 +73,87 @@ > SAVE_2GPRS(7, r11) > .endm > > +.macro SYSCALL_ENTRY trapno > + mfspr r12,SPRN_SPRG_THREAD > + mfcr r10 > + lwz r11,TASK_STACK-THREAD(r12) > + mflr r9 > + addi r11,r11,THREAD_SIZE - INT_FRAME_SIZE > + rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */ > + tophys(r11,r11) > + stw r10,_CCR(r11) /* save registers */ > + mfspr r10,SPRN_SRR0 > + stw r9,_LINK(r11) > + mfspr r9,SPRN_SRR1 > + stw r1,GPR1(r11) > + stw r1,0(r11) > + tovirt(r1,r11) /* set new kernel sp */ > + stw r10,_NIP(r11) > +#ifdef CONFIG_40x > + rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ > +#else > + LOAD_MSR_KERNEL(r10, MSR_KERNEL & ~(MSR_IR|MSR_DR)) /* can take exceptions */ > + MTMSRD(r10) /* (except for mach check in rtas) */ > +#endif > + lis r10,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */ > + stw r2,GPR2(r11) > + addi r10,r10,STACK_FRAME_REGS_MARKER@l > + stw r9,_MSR(r11) > + li r2, \trapno + 1 > + stw r10,8(r11) > + stw r2,_TRAP(r11) > + SAVE_GPR(0, r11) > + SAVE_4GPRS(3, r11) > + SAVE_2GPRS(7, r11) > + addi r11,r1,STACK_FRAME_OVERHEAD > + addi r2,r12,-THREAD > + stw r11,PT_REGS(r12) > +#if defined(CONFIG_40x) > + /* Check to see if the dbcr0 register is set up to debug. Use the > + internal debug mode bit to do this. */ > + lwz r12,THREAD_DBCR0(r12) > + andis. r12,r12,DBCR0_IDM@h > +#endif > + ACCOUNT_CPU_USER_ENTRY(r2, r11, r12) > +#if defined(CONFIG_40x) > + beq+ 3f > + /* From user and task is ptraced - load up global dbcr0 */ > + li r12,-1 /* clear all pending debug events */ > + mtspr SPRN_DBSR,r12 > + lis r11,global_dbcr0@ha > + tophys(r11,r11) > + addi r11,r11,global_dbcr0@l > + lwz r12,0(r11) > + mtspr SPRN_DBCR0,r12 > + lwz r12,4(r11) > + addi r12,r12,-1 > + stw r12,4(r11) > +#endif > + > +3: > + tovirt(r2, r2) /* set r2 to current */ > + lis r11, transfer_to_syscall@h > + ori r11, r11, transfer_to_syscall@l > +#ifdef CONFIG_TRACE_IRQFLAGS > + /* > + * If MSR is changing we need to keep interrupts disabled at this point > + * otherwise we might risk taking an interrupt before we tell lockdep > + * they are enabled. > + */ > + LOAD_MSR_KERNEL(r10, MSR_KERNEL) > + rlwimi r10, r9, 0, MSR_EE > +#else > + LOAD_MSR_KERNEL(r10, MSR_KERNEL | MSR_EE) > +#endif > +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) > + mtspr SPRN_NRI, r0 > +#endif > + mtspr SPRN_SRR1,r10 > + mtspr SPRN_SRR0,r11 > + SYNC > + RFI /* jump to handler, enable MMU */ > +.endm > + > /* > * Note: code which follows this uses cr0.eq (set if from kernel), > * r11, r12 (SRR0), and r9 (SRR1). > @@ -119,8 +200,4 @@ > EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \ > ret_from_except) > > -#define EXC_XFER_SYS(n, hdlr) \ > - EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL | MSR_EE, transfer_to_handler, \ > - ret_from_except) > - > #endif /* __HEAD_32_H__ */ > diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S > index 1afab9190147..f5704488c4fc 100644 > --- a/arch/powerpc/kernel/head_40x.S > +++ b/arch/powerpc/kernel/head_40x.S > @@ -348,8 +348,7 @@ _ENTRY(saved_ksp_limit) > > /* 0x0C00 - System Call Exception */ > START_EXCEPTION(0x0C00, SystemCall) > - EXCEPTION_PROLOG > - EXC_XFER_SYS(0xc00, DoSyscall) > + SYSCALL_ENTRY 0xc00 > > EXCEPTION(0x0D00, Trap_0D, unknown_exception, EXC_XFER_STD) > EXCEPTION(0x0E00, Trap_0E, unknown_exception, EXC_XFER_STD) > diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S > index 336b9921c0da..362b2150a3a0 100644 > --- a/arch/powerpc/kernel/head_8xx.S > +++ b/arch/powerpc/kernel/head_8xx.S > @@ -185,8 +185,7 @@ Alignment: > /* System call */ > . = 0xc00 > SystemCall: > - EXCEPTION_PROLOG > - EXC_XFER_SYS(0xc00, DoSyscall) > + SYSCALL_ENTRY 0xc00 > > /* Single step - not used on 601 */ > EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD) > --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. https://www.avast.com/antivirus
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 1e11528d45ae..137bd2103051 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -335,6 +335,46 @@ 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: + /* + * The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1. + * If from user mode there is only one stack frame on the stack, and + * accessing CALLER_ADDR1 will cause oops. So we need create a dummy + * stack frame to make trace_hardirqs_on happy. + * + */ + stwu r1,-32(r1) + + /* + * 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 + + addi r1,r1,32 + + /* 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. */ @@ -346,9 +386,11 @@ _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 */ diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 3a1df9edf6da..7576e1374a69 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -368,8 +368,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE) . = 0xc00 DO_KVM 0xc00 SystemCall: - EXCEPTION_PROLOG - EXC_XFER_SYS(0xc00, DoSyscall) + SYSCALL_ENTRY 0xc00 /* Single step - not used on 601 */ EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD) diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index 14cb0af2f494..4a692553651f 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -73,6 +73,87 @@ SAVE_2GPRS(7, r11) .endm +.macro SYSCALL_ENTRY trapno + mfspr r12,SPRN_SPRG_THREAD + mfcr r10 + lwz r11,TASK_STACK-THREAD(r12) + mflr r9 + addi r11,r11,THREAD_SIZE - INT_FRAME_SIZE + rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */ + tophys(r11,r11) + stw r10,_CCR(r11) /* save registers */ + mfspr r10,SPRN_SRR0 + stw r9,_LINK(r11) + mfspr r9,SPRN_SRR1 + stw r1,GPR1(r11) + stw r1,0(r11) + tovirt(r1,r11) /* set new kernel sp */ + stw r10,_NIP(r11) +#ifdef CONFIG_40x + rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ +#else + LOAD_MSR_KERNEL(r10, MSR_KERNEL & ~(MSR_IR|MSR_DR)) /* can take exceptions */ + MTMSRD(r10) /* (except for mach check in rtas) */ +#endif + lis r10,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */ + stw r2,GPR2(r11) + addi r10,r10,STACK_FRAME_REGS_MARKER@l + stw r9,_MSR(r11) + li r2, \trapno + 1 + stw r10,8(r11) + stw r2,_TRAP(r11) + SAVE_GPR(0, r11) + SAVE_4GPRS(3, r11) + SAVE_2GPRS(7, r11) + addi r11,r1,STACK_FRAME_OVERHEAD + addi r2,r12,-THREAD + stw r11,PT_REGS(r12) +#if defined(CONFIG_40x) + /* Check to see if the dbcr0 register is set up to debug. Use the + internal debug mode bit to do this. */ + lwz r12,THREAD_DBCR0(r12) + andis. r12,r12,DBCR0_IDM@h +#endif + ACCOUNT_CPU_USER_ENTRY(r2, r11, r12) +#if defined(CONFIG_40x) + beq+ 3f + /* From user and task is ptraced - load up global dbcr0 */ + li r12,-1 /* clear all pending debug events */ + mtspr SPRN_DBSR,r12 + lis r11,global_dbcr0@ha + tophys(r11,r11) + addi r11,r11,global_dbcr0@l + lwz r12,0(r11) + mtspr SPRN_DBCR0,r12 + lwz r12,4(r11) + addi r12,r12,-1 + stw r12,4(r11) +#endif + +3: + tovirt(r2, r2) /* set r2 to current */ + lis r11, transfer_to_syscall@h + ori r11, r11, transfer_to_syscall@l +#ifdef CONFIG_TRACE_IRQFLAGS + /* + * If MSR is changing we need to keep interrupts disabled at this point + * otherwise we might risk taking an interrupt before we tell lockdep + * they are enabled. + */ + LOAD_MSR_KERNEL(r10, MSR_KERNEL) + rlwimi r10, r9, 0, MSR_EE +#else + LOAD_MSR_KERNEL(r10, MSR_KERNEL | MSR_EE) +#endif +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) + mtspr SPRN_NRI, r0 +#endif + mtspr SPRN_SRR1,r10 + mtspr SPRN_SRR0,r11 + SYNC + RFI /* jump to handler, enable MMU */ +.endm + /* * Note: code which follows this uses cr0.eq (set if from kernel), * r11, r12 (SRR0), and r9 (SRR1). @@ -119,8 +200,4 @@ EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \ ret_from_except) -#define EXC_XFER_SYS(n, hdlr) \ - EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL | MSR_EE, transfer_to_handler, \ - ret_from_except) - #endif /* __HEAD_32_H__ */ diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S index 1afab9190147..f5704488c4fc 100644 --- a/arch/powerpc/kernel/head_40x.S +++ b/arch/powerpc/kernel/head_40x.S @@ -348,8 +348,7 @@ _ENTRY(saved_ksp_limit) /* 0x0C00 - System Call Exception */ START_EXCEPTION(0x0C00, SystemCall) - EXCEPTION_PROLOG - EXC_XFER_SYS(0xc00, DoSyscall) + SYSCALL_ENTRY 0xc00 EXCEPTION(0x0D00, Trap_0D, unknown_exception, EXC_XFER_STD) EXCEPTION(0x0E00, Trap_0E, unknown_exception, EXC_XFER_STD) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 336b9921c0da..362b2150a3a0 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -185,8 +185,7 @@ Alignment: /* System call */ . = 0xc00 SystemCall: - EXCEPTION_PROLOG - EXC_XFER_SYS(0xc00, DoSyscall) + SYSCALL_ENTRY 0xc00 /* Single step - not used on 601 */ EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD)
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> --- arch/powerpc/kernel/entry_32.S | 42 +++++++++++++++++++++ arch/powerpc/kernel/head_32.S | 3 +- arch/powerpc/kernel/head_32.h | 85 ++++++++++++++++++++++++++++++++++++++++-- arch/powerpc/kernel/head_40x.S | 3 +- arch/powerpc/kernel/head_8xx.S | 3 +- 5 files changed, 126 insertions(+), 10 deletions(-)