From 1a4b739bbb4f8857d1b4feb46d6b3ec72269c111 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 30 Apr 2019 12:39:03 +0000 Subject: [PATCH] powerpc/32: implement fast entry for syscalls on 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. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/entry_32.S | 7 -- arch/powerpc/kernel/head_44x.S | 3 +- arch/powerpc/kernel/head_booke.h | 103 +++++++++++++++++++++++++-- arch/powerpc/kernel/head_fsl_booke.S | 3 +- 4 files changed, 100 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 184cc1de2f37..dc58fec51ed6 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -342,7 +342,6 @@ 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: /* @@ -369,7 +368,6 @@ transfer_to_syscall: andi. r12,r9,MSR_EE beq- trace_syscall_entry_irq_off #endif /* CONFIG_TRACE_IRQFLAGS */ -#endif /* !CONFIG_BOOKE */ /* * Handle a system call. @@ -382,11 +380,6 @@ _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 diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S index 0381fdb294a6..f15fba58c744 100644 --- a/arch/powerpc/kernel/head_44x.S +++ b/arch/powerpc/kernel/head_44x.S @@ -285,8 +285,7 @@ interrupt_base: #endif /* System Call Interrupt */ START_EXCEPTION(SystemCall) - NORMAL_EXCEPTION_PROLOG(BOOKE_INTERRUPT_SYSCALL) - EXC_XFER_SYS(0x0c00, DoSyscall) + SYSCALL_ENTRY 0xc00 BOOKE_INTERRUPT_SYSCALL /* Auxiliary Processor Unavailable Interrupt */ EXCEPTION(0x2020, BOOKE_INTERRUPT_AP_UNAVAIL, \ diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h index 56dd1341eb3d..bfeb469e8106 100644 --- a/arch/powerpc/kernel/head_booke.h +++ b/arch/powerpc/kernel/head_booke.h @@ -6,6 +6,8 @@ #include #include +#ifdef __ASSEMBLY__ + /* * Macros used for common Book-e exception handling */ @@ -81,6 +83,101 @@ END_BTB_FLUSH_SECTION SAVE_4GPRS(3, r11); \ SAVE_2GPRS(7, r11) +.macro SYSCALL_ENTRY trapno intno + mfspr r10, SPRN_SPRG_THREAD +#ifdef CONFIG_KVM_BOOKE_HV +BEGIN_FTR_SECTION + mtspr SPRN_SPRG_WSCRATCH0, r10 + stw r11, THREAD_NORMSAVE(0)(r10) + stw r13, THREAD_NORMSAVE(2)(r10) + mfcr r13 /* save CR in r13 for now */ + mfspr r11, SPRN_SRR1 + mtocrf 0x80, r11 /* check MSR[GS] without clobbering reg */ + bf 3, 1975f + b kvmppc_handler_BOOKE_INTERRUPT_\intno\()_SPRN_SRR1 +1975: + mr r12, r13 + lwz r13, THREAD_NORMSAVE(2)(r10) +FTR_SECTION_ELSE +#endif + mfcr r12 +#ifdef CONFIG_KVM_BOOKE_HV +ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV) +#endif + BOOKE_CLEAR_BTB(r11) + lwz r11, TASK_STACK - THREAD(r10) + rlwinm r12,r12,0,4,2 /* Clear SO bit in CR */ + ALLOC_STACK_FRAME(r11, THREAD_SIZE - INT_FRAME_SIZE) + stw r12, _CCR(r11) /* save various registers */ + mflr r12 + stw r12,_LINK(r11) + mfspr r12,SPRN_SRR0 + stw r1, GPR1(r11) + mfspr r9,SPRN_SRR1 + stw r1, 0(r11) + mr r1, r11 + stw r12,_NIP(r11) + rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ + lis r12, STACK_FRAME_REGS_MARKER@ha /* exception frame marker */ + stw r2,GPR2(r11) + addi r12, r12, STACK_FRAME_REGS_MARKER@l + stw r9,_MSR(r11) + li r2, \trapno + 1 + stw r12, 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,r10,-THREAD + stw r11,PT_REGS(r10) + /* 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(r10) + andis. r12,r12,DBCR0_IDM@h + ACCOUNT_CPU_USER_ENTRY(r2, r11, r12) + 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 +#ifdef CONFIG_SMP + lwz r9,TASK_CPU(r2) + slwi r9,r9,3 + add r11,r11,r9 +#endif + lwz r12,0(r11) + mtspr SPRN_DBCR0,r12 + lwz r12,4(r11) + addi r12,r12,-1 + stw r12,4(r11) + +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. + */ + lis r10, MSR_KERNEL@h + ori r10, r10, MSR_KERNEL@l + rlwimi r10, r9, 0, MSR_EE +#else + lis r10, (MSR_KERNEL | MSR_EE)@h + ori r10, r10, (MSR_KERNEL | MSR_EE)@l +#endif + mtspr SPRN_SRR1,r10 + mtspr SPRN_SRR0,r11 + SYNC + RFI /* jump to handler, enable MMU */ +.endm + /* To handle the additional exception priority levels on 40x and Book-E * processors we allocate a stack per additional priority level. * @@ -245,10 +342,6 @@ label: 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) - /* Check for a single step debug exception while in an exception * handler before state has been saved. This is to catch the case * where an instruction that we are trying to single step causes @@ -418,7 +511,7 @@ label: 1: addi r3,r1,STACK_FRAME_OVERHEAD; \ EXC_XFER_STD(0x800, kernel_fp_unavailable_exception) -#ifndef __ASSEMBLY__ +#else /* __ASSEMBLY__ */ struct exception_regs { unsigned long mas0; unsigned long mas1; diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S index df980ad0f95f..6621f230cc37 100644 --- a/arch/powerpc/kernel/head_fsl_booke.S +++ b/arch/powerpc/kernel/head_fsl_booke.S @@ -413,8 +413,7 @@ interrupt_base: /* System Call Interrupt */ START_EXCEPTION(SystemCall) - NORMAL_EXCEPTION_PROLOG(SYSCALL) - EXC_XFER_SYS(0x0c00, DoSyscall) + SYSCALL_ENTRY 0xc00 SYSCALL /* Auxiliary Processor Unavailable Interrupt */ EXCEPTION(0x2900, AP_UNAVAIL, AuxillaryProcessorUnavailable, \ -- 2.30.2