From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: To: linuxppc-dev@ozlabs.org Subject: [PATCH] SLB shadow buffer From: Michael Neuling Date: Mon, 07 Aug 2006 16:19:19 +1000 Sender: mikey@ozlabs.org Message-Id: <20060807061920.3E2B7679E9@ozlabs.org> Cc: paulus@samba.org, anton@samba.org, miltonm@bga.com Reply-To: Michael Neuling List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This adds a shadow buffer for the SLBs and regsiters it with PHYP. Only the bolted SLB entries (top 3) are shadowed. Signed-off-by: Michael Neuling --- Updated with comments from Milton. arch/powerpc/kernel/asm-offsets.c | 2 + arch/powerpc/kernel/entry_64.S | 13 ++++++++ arch/powerpc/kernel/paca.c | 15 +++++++++ arch/powerpc/mm/slb.c | 37 +++++++++++++++++++++--- arch/powerpc/platforms/pseries/lpar.c | 24 ++++++++++++--- arch/powerpc/platforms/pseries/plpar_wrappers.h | 10 ++++++ arch/powerpc/platforms/pseries/setup.c | 12 ++++++- include/asm-powerpc/lppaca.h | 19 ++++++++++++ include/asm-powerpc/paca.h | 3 + 9 files changed, 124 insertions(+), 11 deletions(-) Index: linux-2.6-ozlabs/arch/powerpc/kernel/asm-offsets.c =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/kernel/asm-offsets.c +++ linux-2.6-ozlabs/arch/powerpc/kernel/asm-offsets.c @@ -135,11 +135,13 @@ int main(void) DEFINE(PACA_STARTPURR, offsetof(struct paca_struct, startpurr)); DEFINE(PACA_USER_TIME, offsetof(struct paca_struct, user_time)); DEFINE(PACA_SYSTEM_TIME, offsetof(struct paca_struct, system_time)); + DEFINE(PACA_SLBSHADOWPTR, offsetof(struct paca_struct, slb_shadow_ptr)); DEFINE(LPPACASRR0, offsetof(struct lppaca, saved_srr0)); DEFINE(LPPACASRR1, offsetof(struct lppaca, saved_srr1)); DEFINE(LPPACAANYINT, offsetof(struct lppaca, int_dword.any_int)); DEFINE(LPPACADECRINT, offsetof(struct lppaca, int_dword.fields.decr_int)); + DEFINE(SLBSHADOW_SAVEAREA, offsetof(struct slb_shadow, save_area)); #endif /* CONFIG_PPC64 */ /* RTAS */ Index: linux-2.6-ozlabs/arch/powerpc/kernel/entry_64.S =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/kernel/entry_64.S +++ linux-2.6-ozlabs/arch/powerpc/kernel/entry_64.S @@ -323,6 +323,11 @@ _GLOBAL(ret_from_fork) * The code which creates the new task context is in 'copy_thread' * in arch/powerpc/kernel/process.c */ +#define SHADOW_SLB_BOLTED_STACK_ESID \ + (SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1)) +#define SHADOW_SLB_BOLTED_STACK_VSID \ + (SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1) + 8) + .align 7 _GLOBAL(_switch) mflr r0 @@ -375,6 +380,14 @@ BEGIN_FTR_SECTION ld r7,KSP_VSID(r4) /* Get new stack's VSID */ oris r0,r6,(SLB_ESID_V)@h ori r0,r0,(SLB_NUM_BOLTED-1)@l + + /* Update the last bolted SLB */ + ld r9,PACA_SLBSHADOWPTR(r13) + li r12,0 + std r12,SHADOW_SLB_BOLTED_STACK_ESID(r9) /* Clear ESID */ + std r7,SHADOW_SLB_BOLTED_STACK_VSID(r9) /* Save VSID */ + std r0,SHADOW_SLB_BOLTED_STACK_ESID(r9) /* Save ESID */ + slbie r6 slbie r6 /* Workaround POWER5 < DD2.1 issue */ slbmte r7,r0 Index: linux-2.6-ozlabs/arch/powerpc/kernel/paca.c =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/kernel/paca.c +++ linux-2.6-ozlabs/arch/powerpc/kernel/paca.c @@ -17,6 +17,7 @@ #include #include #include +#include /* This symbol is provided by the linker - let it fill in the paca @@ -45,6 +46,17 @@ struct lppaca lppaca[] = { }, }; +/* + * 3 persistent SLBs are registered here. The buffer will be zero + * initially, hence will all be invaild until we actually write them. + */ +struct slb_shadow slb_shadow[] __cacheline_aligned = { + [0 ... (NR_CPUS-1)] = { + .persistent = SLB_NUM_BOLTED, + .buffer_length = sizeof(struct slb_shadow), + }, +}; + /* The Paca is an array with one entry per processor. Each contains an * lppaca, which contains the information shared between the * hypervisor and Linux. @@ -59,7 +71,8 @@ struct lppaca lppaca[] = { .lock_token = 0x8000, \ .paca_index = (number), /* Paca Index */ \ .kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL, \ - .hw_cpu_id = 0xffff, + .hw_cpu_id = 0xffff, \ + .slb_shadow_ptr = &slb_shadow[number], #ifdef CONFIG_PPC_ISERIES #define PACA_INIT_ISERIES(number) \ Index: linux-2.6-ozlabs/arch/powerpc/mm/slb.c =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/mm/slb.c +++ linux-2.6-ozlabs/arch/powerpc/mm/slb.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #ifdef DEBUG #define DBG(fmt...) udbg_printf(fmt) @@ -50,9 +52,32 @@ static inline unsigned long mk_vsid_data return (get_kernel_vsid(ea) << SLB_VSID_SHIFT) | flags; } -static inline void create_slbe(unsigned long ea, unsigned long flags, - unsigned long entry) +static inline void slb_shadow_update(unsigned long esid, unsigned long vsid, + unsigned long entry) { + /* + * Clear the ESID first so the entry is not valid while we are + * updating it. + */ + get_slb_shadow()->save_area[entry].esid = 0; + barrier(); + get_slb_shadow()->save_area[entry].vsid = vsid; + barrier(); + get_slb_shadow()->save_area[entry].esid = esid; + +} + +static inline void create_shadowed_slbe(unsigned long ea, unsigned long flags, + unsigned long entry) +{ + /* + * Updating the shadow buffer before writing the SLB ensures + * we don't get a stale entry here if we get preempted by PHYP + * between these two statements. + */ + slb_shadow_update(mk_esid_data(ea, entry), mk_vsid_data(ea, flags), + entry); + asm volatile("slbmte %0,%1" : : "r" (mk_vsid_data(ea, flags)), "r" (mk_esid_data(ea, entry)) @@ -77,6 +102,10 @@ void slb_flush_and_rebolt(void) if ((ksp_esid_data & ESID_MASK) == PAGE_OFFSET) ksp_esid_data &= ~SLB_ESID_V; + /* Only third entry (stack) may change here so only resave that */ + slb_shadow_update(ksp_esid_data, + mk_vsid_data(ksp_esid_data, lflags), 2); + /* We need to do this all in asm, so we're sure we don't touch * the stack between the slbia and rebolting it. */ asm volatile("isync\n" @@ -209,9 +238,9 @@ void slb_initialize(void) asm volatile("isync":::"memory"); asm volatile("slbmte %0,%0"::"r" (0) : "memory"); asm volatile("isync; slbia; isync":::"memory"); - create_slbe(PAGE_OFFSET, lflags, 0); + create_shadowed_slbe(PAGE_OFFSET, lflags, 0); - create_slbe(VMALLOC_START, vflags, 1); + create_shadowed_slbe(VMALLOC_START, vflags, 1); /* We don't bolt the stack for the time being - we're in boot, * so the stack is in the bolted segment. By the time it goes Index: linux-2.6-ozlabs/arch/powerpc/platforms/pseries/lpar.c =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/platforms/pseries/lpar.c +++ linux-2.6-ozlabs/arch/powerpc/platforms/pseries/lpar.c @@ -254,18 +254,34 @@ out: void vpa_init(int cpu) { int hwcpu = get_hard_smp_processor_id(cpu); - unsigned long vpa = __pa(&lppaca[cpu]); + unsigned long addr; long ret; if (cpu_has_feature(CPU_FTR_ALTIVEC)) lppaca[cpu].vmxregs_in_use = 1; - ret = register_vpa(hwcpu, vpa); + addr = __pa(&lppaca[cpu]); + ret = register_vpa(hwcpu, addr); - if (ret) + if (ret) { printk(KERN_ERR "WARNING: vpa_init: VPA registration for " "cpu %d (hw %d) of area %lx returns %ld\n", - cpu, hwcpu, vpa, ret); + cpu, hwcpu, addr, ret); + return; + } + /* + * PAPR says this feature is SLB-Buffer but firmware never + * reports that. All SPLPAR support SLB shadow buffer. + */ + addr = __pa(&slb_shadow[cpu]); + if (firmware_has_feature(FW_FEATURE_SPLPAR)) { + ret = register_slb_shadow(hwcpu, addr); + if (ret) + printk(KERN_ERR + "WARNING: vpa_init: SLB shadow buffer " + "registration for cpu %d (hw %d) of area %lx " + "returns %ld\n", cpu, hwcpu, addr, ret); + } } long pSeries_lpar_hpte_insert(unsigned long hpte_group, Index: linux-2.6-ozlabs/arch/powerpc/platforms/pseries/plpar_wrappers.h =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/platforms/pseries/plpar_wrappers.h +++ linux-2.6-ozlabs/arch/powerpc/platforms/pseries/plpar_wrappers.h @@ -40,6 +40,16 @@ static inline long register_vpa(unsigned return vpa_call(0x1, cpu, vpa); } +static inline long unregister_slb_shadow(unsigned long cpu, unsigned long vpa) +{ + return vpa_call(0x7, cpu, vpa); +} + +static inline long register_slb_shadow(unsigned long cpu, unsigned long vpa) +{ + return vpa_call(0x3, cpu, vpa); +} + extern void vpa_init(int cpu); static inline long plpar_pte_remove(unsigned long flags, unsigned long ptex, Index: linux-2.6-ozlabs/arch/powerpc/platforms/pseries/setup.c =================================================================== --- linux-2.6-ozlabs.orig/arch/powerpc/platforms/pseries/setup.c +++ linux-2.6-ozlabs/arch/powerpc/platforms/pseries/setup.c @@ -234,9 +234,17 @@ static void pseries_kexec_cpu_down_xics( { /* Don't risk a hypervisor call if we're crashing */ if (firmware_has_feature(FW_FEATURE_SPLPAR) && !crash_shutdown) { - unsigned long vpa = __pa(get_lppaca()); + unsigned long addr; - if (unregister_vpa(hard_smp_processor_id(), vpa)) { + addr = __pa(get_slb_shadow()); + if (unregister_slb_shadow(hard_smp_processor_id(), addr)) + printk("SLB shadow buffer deregistration of " + "cpu %u (hw_cpu_id %d) failed\n", + smp_processor_id(), + hard_smp_processor_id()); + + addr = __pa(get_lppaca()); + if (unregister_vpa(hard_smp_processor_id(), addr)) { printk("VPA deregistration of cpu %u (hw_cpu_id %d) " "failed\n", smp_processor_id(), hard_smp_processor_id()); Index: linux-2.6-ozlabs/include/asm-powerpc/lppaca.h =================================================================== --- linux-2.6-ozlabs.orig/include/asm-powerpc/lppaca.h +++ linux-2.6-ozlabs/include/asm-powerpc/lppaca.h @@ -27,7 +27,9 @@ // // //---------------------------------------------------------------------------- +#include #include +#include /* The Hypervisor barfs if the lppaca crosses a page boundary. A 1k * alignment is sufficient to prevent this */ @@ -133,5 +135,22 @@ struct lppaca { extern struct lppaca lppaca[]; +/* + * SLB shadow buffer structure as defined in the PAPR. The save_area + * contains adjacent ESID and VSID pairs for each shadowed SLB. The + * ESID is stored in the lower 64bits, then the VSID. + */ +struct slb_shadow { + u32 persistent; // Number of persistent SLBs x00-x03 + u32 buffer_length; // Total shadow buffer length x04-x07 + u64 reserved; // Alignment x08-x0f + struct { + u64 esid; + u64 vsid; + } save_area[SLB_NUM_BOLTED]; // x10-x40 +} ____cacheline_aligned; + +extern struct slb_shadow slb_shadow[]; + #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_LPPACA_H */ Index: linux-2.6-ozlabs/include/asm-powerpc/paca.h =================================================================== --- linux-2.6-ozlabs.orig/include/asm-powerpc/paca.h +++ linux-2.6-ozlabs/include/asm-powerpc/paca.h @@ -23,6 +23,7 @@ register struct paca_struct *local_paca asm("r13"); #define get_paca() local_paca #define get_lppaca() (get_paca()->lppaca_ptr) +#define get_slb_shadow() (get_paca()->slb_shadow_ptr) struct task_struct; @@ -98,6 +99,8 @@ struct paca_struct { u64 user_time; /* accumulated usermode TB ticks */ u64 system_time; /* accumulated system TB ticks */ u64 startpurr; /* PURR/TB value snapshot */ + + struct slb_shadow *slb_shadow_ptr; }; extern struct paca_struct paca[];