[PATCH] SLB shadow buffer
Michael Neuling
mikey at neuling.org
Tue Aug 8 14:29:17 EST 2006
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 <mikey at neuling.org>
---
Updated with more comments from Milton
arch/powerpc/kernel/asm-offsets.c | 7 ++++
arch/powerpc/kernel/entry_64.S | 8 +++++
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
@@ -42,6 +42,7 @@
#include <asm/lppaca.h>
#include <asm/cache.h>
#include <asm/compat.h>
+#include <asm/mmu.h>
#endif
#define DEFINE(sym, val) \
@@ -135,11 +136,17 @@ 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_STACKVSID,
+ offsetof(struct slb_shadow, save_area[SLB_NUM_BOLTED - 1].vsid));
+ DEFINE(SLBSHADOW_STACKESID,
+ offsetof(struct slb_shadow, save_area[SLB_NUM_BOLTED - 1].esid));
#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
@@ -375,6 +375,14 @@ 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,SLBSHADOW_STACKESID(r9) /* Clear ESID */
+ std r7,SLBSHADOW_STACKVSID(r9) /* Save VSID */
+ std r0,SLBSHADOW_STACKESID(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 <asm/lppaca.h>
#include <asm/iseries/it_lp_reg_save.h>
#include <asm/paca.h>
+#include <asm/mmu.h>
/* 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 <asm/paca.h>
#include <asm/cputable.h>
#include <asm/cacheflush.h>
+#include <asm/smp.h>
+#include <linux/compiler.h>
#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 <linux/cache.h>
#include <asm/types.h>
+#include <asm/mmu.h>
/* 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]; /* Actual SLB Save buffer 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[];
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