From 028474876f472c3b6eee633aed528a1206609657 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Sat, 21 Dec 2019 08:32:27 +0000 Subject: [PATCH] powerpc/32: prepare for CONFIG_VMAP_STACK To support CONFIG_VMAP_STACK, the kernel has to activate Data MMU Translation for accessing the stack. Before doing that it must save SRR0, SRR1 and also DAR and DSISR when relevant, in order to not loose them in case there is a Data TLB Miss once the translation is reactivated. This patch adds fields in thread struct for saving those registers. It prepares entry_32.S to handle exception entry with Data MMU Translation enabled and alters EXCEPTION_PROLOG macros to save SRR0, SRR1, DAR and DSISR then reenables Data MMU. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/a775a1fea60f190e0f63503463fb775310a2009b.1576916812.git.christophe.leroy@c-s.fr --- arch/powerpc/include/asm/processor.h | 6 ++ arch/powerpc/include/asm/thread_info.h | 5 ++ arch/powerpc/kernel/asm-offsets.c | 6 ++ arch/powerpc/kernel/entry_32.S | 4 +- arch/powerpc/kernel/head_32.h | 128 +++++++++++++++++++++++++++++---- 5 files changed, 133 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index e114eb3..8387698 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -163,6 +163,12 @@ struct thread_struct { #if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP) unsigned long kuap; /* opened segments for user access */ #endif +#ifdef CONFIG_VMAP_STACK + unsigned long srr0; + unsigned long srr1; + unsigned long dar; + unsigned long dsisr; +#endif /* Debug Registers */ struct debug_reg debug; struct thread_fp_state fp_state; diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index 8e1d019..488d5c4 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -10,10 +10,15 @@ #define _ASM_POWERPC_THREAD_INFO_H #include +#include #ifdef __KERNEL__ +#if defined(CONFIG_VMAP_STACK) && CONFIG_THREAD_SHIFT < PAGE_SHIFT +#define THREAD_SHIFT PAGE_SHIFT +#else #define THREAD_SHIFT CONFIG_THREAD_SHIFT +#endif #define THREAD_SIZE (1 << THREAD_SHIFT) diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 90e53d4..c25e562 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -127,6 +127,12 @@ int main(void) OFFSET(KSP_VSID, thread_struct, ksp_vsid); #else /* CONFIG_PPC64 */ OFFSET(PGDIR, thread_struct, pgdir); +#ifdef CONFIG_VMAP_STACK + OFFSET(SRR0, thread_struct, srr0); + OFFSET(SRR1, thread_struct, srr1); + OFFSET(DAR, thread_struct, dar); + OFFSET(DSISR, thread_struct, dsisr); +#endif #ifdef CONFIG_SPE OFFSET(THREAD_EVR0, thread_struct, evr[0]); OFFSET(THREAD_ACC, thread_struct, acc); diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 317ad9d..8f6617c 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -140,6 +140,7 @@ transfer_to_handler: stw r12,_CTR(r11) stw r2,_XER(r11) mfspr r12,SPRN_SPRG_THREAD + tovirt_vmstack r12, r12 beq 2f /* if from user, fix up THREAD.regs */ addi r2, r12, -THREAD addi r11,r1,STACK_FRAME_OVERHEAD @@ -195,7 +196,8 @@ transfer_to_handler: transfer_to_handler_cont: 3: mflr r9 - tovirt(r2, r2) /* set r2 to current */ + tovirt_novmstack r2, r2 /* set r2 to current */ + tovirt_vmstack r9, r9 lwz r11,0(r9) /* virtual address of handler */ lwz r9,4(r9) /* where to go when done */ #if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index f19a1ab..e36987a 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -10,31 +10,54 @@ * We assume sprg3 has the physical address of the current * task's thread_struct. */ -.macro EXCEPTION_PROLOG - EXCEPTION_PROLOG_0 +.macro EXCEPTION_PROLOG handle_dar_dsisr=0 + EXCEPTION_PROLOG_0 handle_dar_dsisr=\handle_dar_dsisr EXCEPTION_PROLOG_1 - EXCEPTION_PROLOG_2 + EXCEPTION_PROLOG_2 handle_dar_dsisr=\handle_dar_dsisr .endm -.macro EXCEPTION_PROLOG_0 +.macro EXCEPTION_PROLOG_0 handle_dar_dsisr=0 mtspr SPRN_SPRG_SCRATCH0,r10 mtspr SPRN_SPRG_SCRATCH1,r11 +#ifdef CONFIG_VMAP_STACK + mfspr r10, SPRN_SPRG_THREAD + .if \handle_dar_dsisr + mfspr r11, SPRN_DAR + stw r11, DAR(r10) + mfspr r11, SPRN_DSISR + stw r11, DSISR(r10) + .endif + mfspr r11, SPRN_SRR0 + stw r11, SRR0(r10) +#endif mfspr r11, SPRN_SRR1 /* check whether user or kernel */ +#ifdef CONFIG_VMAP_STACK + stw r11, SRR1(r10) +#endif mfcr r10 andi. r11, r11, MSR_PR .endm .macro EXCEPTION_PROLOG_1 +#ifdef CONFIG_VMAP_STACK + li r11, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */ + mtmsr r11 + isync + subi r11, r1, INT_FRAME_SIZE /* use r1 if kernel */ +#else tophys(r11,r1) /* use tophys(r1) if kernel */ + subi r11, r11, INT_FRAME_SIZE /* alloc exc. frame */ +#endif beq 1f mfspr r11,SPRN_SPRG_THREAD + tovirt_vmstack r11, r11 lwz r11,TASK_STACK-THREAD(r11) - addi r11,r11,THREAD_SIZE - tophys(r11,r11) -1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */ + addi r11, r11, THREAD_SIZE - INT_FRAME_SIZE + tophys_novmstack r11, r11 +1: .endm -.macro EXCEPTION_PROLOG_2 +.macro EXCEPTION_PROLOG_2 handle_dar_dsisr=0 stw r10,_CCR(r11) /* save registers */ stw r12,GPR12(r11) stw r9,GPR9(r11) @@ -44,15 +67,32 @@ stw r12,GPR11(r11) mflr r10 stw r10,_LINK(r11) +#ifdef CONFIG_VMAP_STACK + mfspr r12, SPRN_SPRG_THREAD + tovirt(r12, r12) + .if \handle_dar_dsisr + lwz r10, DAR(r12) + stw r10, _DAR(r11) + lwz r10, DSISR(r12) + stw r10, _DSISR(r11) + .endif + lwz r9, SRR1(r12) + lwz r12, SRR0(r12) +#else mfspr r12,SPRN_SRR0 mfspr r9,SPRN_SRR1 +#endif stw r1,GPR1(r11) stw r1,0(r11) - tovirt(r1,r11) /* set new kernel sp */ + tovirt_novmstack r1, r11 /* set new kernel sp */ #ifdef CONFIG_40x rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ #else +#ifdef CONFIG_VMAP_STACK + li r10, MSR_KERNEL & ~MSR_IR /* can take exceptions */ +#else li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR) /* can take exceptions */ +#endif mtmsr r10 /* (except for mach check in rtas) */ #endif stw r0,GPR0(r11) @@ -65,24 +105,45 @@ .macro SYSCALL_ENTRY trapno mfspr r12,SPRN_SPRG_THREAD +#ifdef CONFIG_VMAP_STACK + mfspr r9, SPRN_SRR0 + mfspr r11, SPRN_SRR1 + stw r9, SRR0(r12) + stw r11, SRR1(r12) +#endif 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) + addi r11, r11, THREAD_SIZE - INT_FRAME_SIZE +#ifdef CONFIG_VMAP_STACK + li r9, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */ + mtmsr r9 + isync +#endif + tovirt_vmstack r12, r12 + tophys_novmstack r11, r11 + mflr r9 stw r10,_CCR(r11) /* save registers */ + stw r9, _LINK(r11) +#ifdef CONFIG_VMAP_STACK + lwz r10, SRR0(r12) + lwz r9, SRR1(r12) +#else mfspr r10,SPRN_SRR0 - stw r9,_LINK(r11) mfspr r9,SPRN_SRR1 +#endif stw r1,GPR1(r11) stw r1,0(r11) - tovirt(r1,r11) /* set new kernel sp */ + tovirt_novmstack r1, r11 /* set new kernel sp */ stw r10,_NIP(r11) #ifdef CONFIG_40x rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ #else +#ifdef CONFIG_VMAP_STACK + LOAD_REG_IMMEDIATE(r10, MSR_KERNEL & ~MSR_IR) /* can take exceptions */ +#else LOAD_REG_IMMEDIATE(r10, MSR_KERNEL & ~(MSR_IR|MSR_DR)) /* can take exceptions */ +#endif mtmsr r10 /* (except for mach check in rtas) */ #endif lis r10,STACK_FRAME_REGS_MARKER@ha /* exception frame marker */ @@ -121,7 +182,7 @@ #endif 3: - tovirt(r2, r2) /* set r2 to current */ + tovirt_novmstack r2, r2 /* set r2 to current */ lis r11, transfer_to_syscall@h ori r11, r11, transfer_to_syscall@l #ifdef CONFIG_TRACE_IRQFLAGS @@ -145,14 +206,51 @@ .endm .macro save_dar_dsisr_on_stack reg1, reg2, sp +#ifndef CONFIG_VMAP_STACK mfspr \reg1, SPRN_DAR mfspr \reg2, SPRN_DSISR stw \reg1, _DAR(\sp) stw \reg2, _DSISR(\sp) +#endif .endm .macro get_and_save_dar_dsisr_on_stack reg1, reg2, sp +#ifdef CONFIG_VMAP_STACK + lwz \reg1, _DAR(\sp) + lwz \reg2, _DSISR(\sp) +#else save_dar_dsisr_on_stack \reg1, \reg2, \sp +#endif +.endm + +.macro tovirt_vmstack dst, src +#ifdef CONFIG_VMAP_STACK + tovirt(\dst, \src) +#else + .ifnc \dst, \src + mr \dst, \src + .endif +#endif +.endm + +.macro tovirt_novmstack dst, src +#ifndef CONFIG_VMAP_STACK + tovirt(\dst, \src) +#else + .ifnc \dst, \src + mr \dst, \src + .endif +#endif +.endm + +.macro tophys_novmstack dst, src +#ifndef CONFIG_VMAP_STACK + tophys(\dst, \src) +#else + .ifnc \dst, \src + mr \dst, \src + .endif +#endif .endm /* -- 2.7.4