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-rw-r--r--arch/powerpc/mm/slb.c784
1 files changed, 555 insertions, 229 deletions
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index 9f574e59d178..c3fdf2969d9f 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -14,6 +14,7 @@
* 2 of the License, or (at your option) any later version.
*/
+#include <asm/asm-prototypes.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
@@ -30,11 +31,10 @@
enum slb_index {
LINEAR_INDEX = 0, /* Kernel linear map (0xc000000000000000) */
- VMALLOC_INDEX = 1, /* Kernel virtual map (0xd000000000000000) */
- KSTACK_INDEX = 2, /* Kernel stack map */
+ KSTACK_INDEX = 1, /* Kernel stack map */
};
-extern void slb_allocate(unsigned long ea);
+static long slb_allocate_user(struct mm_struct *mm, unsigned long ea);
#define slb_esid_mask(ssize) \
(((ssize) == MMU_SEGSIZE_256M)? ESID_MASK: ESID_MASK_1T)
@@ -45,13 +45,43 @@ static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | index;
}
-static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
+static inline unsigned long __mk_vsid_data(unsigned long vsid, int ssize,
unsigned long flags)
{
- return (get_kernel_vsid(ea, ssize) << slb_vsid_shift(ssize)) | flags |
+ return (vsid << slb_vsid_shift(ssize)) | flags |
((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
}
+static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
+ unsigned long flags)
+{
+ return __mk_vsid_data(get_kernel_vsid(ea, ssize), ssize, flags);
+}
+
+static void assert_slb_exists(unsigned long ea)
+{
+#ifdef CONFIG_DEBUG_VM
+ unsigned long tmp;
+
+ WARN_ON_ONCE(mfmsr() & MSR_EE);
+
+ asm volatile("slbfee. %0, %1" : "=r"(tmp) : "r"(ea) : "cr0");
+ WARN_ON(tmp == 0);
+#endif
+}
+
+static void assert_slb_notexists(unsigned long ea)
+{
+#ifdef CONFIG_DEBUG_VM
+ unsigned long tmp;
+
+ WARN_ON_ONCE(mfmsr() & MSR_EE);
+
+ asm volatile("slbfee. %0, %1" : "=r"(tmp) : "r"(ea) : "cr0");
+ WARN_ON(tmp != 0);
+#endif
+}
+
static inline void slb_shadow_update(unsigned long ea, int ssize,
unsigned long flags,
enum slb_index index)
@@ -84,6 +114,7 @@ static inline void create_shadowed_slbe(unsigned long ea, int ssize,
*/
slb_shadow_update(ea, ssize, flags, index);
+ assert_slb_notexists(ea);
asm volatile("slbmte %0,%1" :
: "r" (mk_vsid_data(ea, ssize, flags)),
"r" (mk_esid_data(ea, ssize, index))
@@ -105,17 +136,20 @@ void __slb_restore_bolted_realmode(void)
: "r" (be64_to_cpu(p->save_area[index].vsid)),
"r" (be64_to_cpu(p->save_area[index].esid)));
}
+
+ assert_slb_exists(local_paca->kstack);
}
/*
* Insert the bolted entries into an empty SLB.
- * This is not the same as rebolt because the bolted segments are not
- * changed, just loaded from the shadow area.
*/
void slb_restore_bolted_realmode(void)
{
__slb_restore_bolted_realmode();
get_paca()->slb_cache_ptr = 0;
+
+ get_paca()->slb_kern_bitmap = (1U << SLB_NUM_BOLTED) - 1;
+ get_paca()->slb_used_bitmap = get_paca()->slb_kern_bitmap;
}
/*
@@ -123,113 +157,262 @@ void slb_restore_bolted_realmode(void)
*/
void slb_flush_all_realmode(void)
{
- /*
- * This flushes all SLB entries including 0, so it must be realmode.
- */
asm volatile("slbmte %0,%0; slbia" : : "r" (0));
}
-static void __slb_flush_and_rebolt(void)
+/*
+ * This flushes non-bolted entries, it can be run in virtual mode. Must
+ * be called with interrupts disabled.
+ */
+void slb_flush_and_restore_bolted(void)
{
- /* If you change this make sure you change SLB_NUM_BOLTED
- * and PR KVM appropriately too. */
- unsigned long linear_llp, vmalloc_llp, lflags, vflags;
- unsigned long ksp_esid_data, ksp_vsid_data;
+ struct slb_shadow *p = get_slb_shadow();
- linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
- vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp;
- lflags = SLB_VSID_KERNEL | linear_llp;
- vflags = SLB_VSID_KERNEL | vmalloc_llp;
+ BUILD_BUG_ON(SLB_NUM_BOLTED != 2);
- ksp_esid_data = mk_esid_data(get_paca()->kstack, mmu_kernel_ssize, KSTACK_INDEX);
- if ((ksp_esid_data & ~0xfffffffUL) <= PAGE_OFFSET) {
- ksp_esid_data &= ~SLB_ESID_V;
- ksp_vsid_data = 0;
- slb_shadow_clear(KSTACK_INDEX);
- } else {
- /* Update stack entry; others don't change */
- slb_shadow_update(get_paca()->kstack, mmu_kernel_ssize, lflags, KSTACK_INDEX);
- ksp_vsid_data =
- be64_to_cpu(get_slb_shadow()->save_area[KSTACK_INDEX].vsid);
- }
+ WARN_ON(!irqs_disabled());
+
+ /*
+ * We can't take a PMU exception in the following code, so hard
+ * disable interrupts.
+ */
+ hard_irq_disable();
- /* 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"
"slbia\n"
- /* Slot 1 - first VMALLOC segment */
- "slbmte %0,%1\n"
- /* Slot 2 - kernel stack */
- "slbmte %2,%3\n"
- "isync"
- :: "r"(mk_vsid_data(VMALLOC_START, mmu_kernel_ssize, vflags)),
- "r"(mk_esid_data(VMALLOC_START, mmu_kernel_ssize, VMALLOC_INDEX)),
- "r"(ksp_vsid_data),
- "r"(ksp_esid_data)
+ "slbmte %0, %1\n"
+ "isync\n"
+ :: "r" (be64_to_cpu(p->save_area[KSTACK_INDEX].vsid)),
+ "r" (be64_to_cpu(p->save_area[KSTACK_INDEX].esid))
: "memory");
+ assert_slb_exists(get_paca()->kstack);
+
+ get_paca()->slb_cache_ptr = 0;
+
+ get_paca()->slb_kern_bitmap = (1U << SLB_NUM_BOLTED) - 1;
+ get_paca()->slb_used_bitmap = get_paca()->slb_kern_bitmap;
}
-void slb_flush_and_rebolt(void)
+void slb_save_contents(struct slb_entry *slb_ptr)
{
+ int i;
+ unsigned long e, v;
- WARN_ON(!irqs_disabled());
+ /* Save slb_cache_ptr value. */
+ get_paca()->slb_save_cache_ptr = get_paca()->slb_cache_ptr;
+
+ if (!slb_ptr)
+ return;
+
+ for (i = 0; i < mmu_slb_size; i++) {
+ asm volatile("slbmfee %0,%1" : "=r" (e) : "r" (i));
+ asm volatile("slbmfev %0,%1" : "=r" (v) : "r" (i));
+ slb_ptr->esid = e;
+ slb_ptr->vsid = v;
+ slb_ptr++;
+ }
+}
+
+void slb_dump_contents(struct slb_entry *slb_ptr)
+{
+ int i, n;
+ unsigned long e, v;
+ unsigned long llp;
+
+ if (!slb_ptr)
+ return;
+
+ pr_err("SLB contents of cpu 0x%x\n", smp_processor_id());
+ pr_err("Last SLB entry inserted at slot %d\n", get_paca()->stab_rr);
+
+ for (i = 0; i < mmu_slb_size; i++) {
+ e = slb_ptr->esid;
+ v = slb_ptr->vsid;
+ slb_ptr++;
+
+ if (!e && !v)
+ continue;
+
+ pr_err("%02d %016lx %016lx\n", i, e, v);
+
+ if (!(e & SLB_ESID_V)) {
+ pr_err("\n");
+ continue;
+ }
+ llp = v & SLB_VSID_LLP;
+ if (v & SLB_VSID_B_1T) {
+ pr_err(" 1T ESID=%9lx VSID=%13lx LLP:%3lx\n",
+ GET_ESID_1T(e),
+ (v & ~SLB_VSID_B) >> SLB_VSID_SHIFT_1T, llp);
+ } else {
+ pr_err(" 256M ESID=%9lx VSID=%13lx LLP:%3lx\n",
+ GET_ESID(e),
+ (v & ~SLB_VSID_B) >> SLB_VSID_SHIFT, llp);
+ }
+ }
+ pr_err("----------------------------------\n");
+
+ /* Dump slb cache entires as well. */
+ pr_err("SLB cache ptr value = %d\n", get_paca()->slb_save_cache_ptr);
+ pr_err("Valid SLB cache entries:\n");
+ n = min_t(int, get_paca()->slb_save_cache_ptr, SLB_CACHE_ENTRIES);
+ for (i = 0; i < n; i++)
+ pr_err("%02d EA[0-35]=%9x\n", i, get_paca()->slb_cache[i]);
+ pr_err("Rest of SLB cache entries:\n");
+ for (i = n; i < SLB_CACHE_ENTRIES; i++)
+ pr_err("%02d EA[0-35]=%9x\n", i, get_paca()->slb_cache[i]);
+}
+void slb_vmalloc_update(void)
+{
/*
- * We can't take a PMU exception in the following code, so hard
- * disable interrupts.
+ * vmalloc is not bolted, so just have to flush non-bolted.
*/
- hard_irq_disable();
+ slb_flush_and_restore_bolted();
+}
- __slb_flush_and_rebolt();
- get_paca()->slb_cache_ptr = 0;
+static bool preload_hit(struct thread_info *ti, unsigned long esid)
+{
+ unsigned char i;
+
+ for (i = 0; i < ti->slb_preload_nr; i++) {
+ unsigned char idx;
+
+ idx = (ti->slb_preload_tail + i) % SLB_PRELOAD_NR;
+ if (esid == ti->slb_preload_esid[idx])
+ return true;
+ }
+ return false;
}
-void slb_vmalloc_update(void)
+static bool preload_add(struct thread_info *ti, unsigned long ea)
{
- unsigned long vflags;
+ unsigned char idx;
+ unsigned long esid;
+
+ if (mmu_has_feature(MMU_FTR_1T_SEGMENT)) {
+ /* EAs are stored >> 28 so 256MB segments don't need clearing */
+ if (ea & ESID_MASK_1T)
+ ea &= ESID_MASK_1T;
+ }
+
+ esid = ea >> SID_SHIFT;
- vflags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmalloc_psize].sllp;
- slb_shadow_update(VMALLOC_START, mmu_kernel_ssize, vflags, VMALLOC_INDEX);
- slb_flush_and_rebolt();
+ if (preload_hit(ti, esid))
+ return false;
+
+ idx = (ti->slb_preload_tail + ti->slb_preload_nr) % SLB_PRELOAD_NR;
+ ti->slb_preload_esid[idx] = esid;
+ if (ti->slb_preload_nr == SLB_PRELOAD_NR)
+ ti->slb_preload_tail = (ti->slb_preload_tail + 1) % SLB_PRELOAD_NR;
+ else
+ ti->slb_preload_nr++;
+
+ return true;
}
-/* Helper function to compare esids. There are four cases to handle.
- * 1. The system is not 1T segment size capable. Use the GET_ESID compare.
- * 2. The system is 1T capable, both addresses are < 1T, use the GET_ESID compare.
- * 3. The system is 1T capable, only one of the two addresses is > 1T. This is not a match.
- * 4. The system is 1T capable, both addresses are > 1T, use the GET_ESID_1T macro to compare.
- */
-static inline int esids_match(unsigned long addr1, unsigned long addr2)
+static void preload_age(struct thread_info *ti)
{
- int esid_1t_count;
+ if (!ti->slb_preload_nr)
+ return;
+ ti->slb_preload_nr--;
+ ti->slb_preload_tail = (ti->slb_preload_tail + 1) % SLB_PRELOAD_NR;
+}
- /* System is not 1T segment size capable. */
- if (!mmu_has_feature(MMU_FTR_1T_SEGMENT))
- return (GET_ESID(addr1) == GET_ESID(addr2));
+void slb_setup_new_exec(void)
+{
+ struct thread_info *ti = current_thread_info();
+ struct mm_struct *mm = current->mm;
+ unsigned long exec = 0x10000000;
- esid_1t_count = (((addr1 >> SID_SHIFT_1T) != 0) +
- ((addr2 >> SID_SHIFT_1T) != 0));
+ WARN_ON(irqs_disabled());
- /* both addresses are < 1T */
- if (esid_1t_count == 0)
- return (GET_ESID(addr1) == GET_ESID(addr2));
+ /*
+ * preload cache can only be used to determine whether a SLB
+ * entry exists if it does not start to overflow.
+ */
+ if (ti->slb_preload_nr + 2 > SLB_PRELOAD_NR)
+ return;
- /* One address < 1T, the other > 1T. Not a match */
- if (esid_1t_count == 1)
- return 0;
+ hard_irq_disable();
- /* Both addresses are > 1T. */
- return (GET_ESID_1T(addr1) == GET_ESID_1T(addr2));
+ /*
+ * We have no good place to clear the slb preload cache on exec,
+ * flush_thread is about the earliest arch hook but that happens
+ * after we switch to the mm and have aleady preloaded the SLBEs.
+ *
+ * For the most part that's probably okay to use entries from the
+ * previous exec, they will age out if unused. It may turn out to
+ * be an advantage to clear the cache before switching to it,
+ * however.
+ */
+
+ /*
+ * preload some userspace segments into the SLB.
+ * Almost all 32 and 64bit PowerPC executables are linked at
+ * 0x10000000 so it makes sense to preload this segment.
+ */
+ if (!is_kernel_addr(exec)) {
+ if (preload_add(ti, exec))
+ slb_allocate_user(mm, exec);
+ }
+
+ /* Libraries and mmaps. */
+ if (!is_kernel_addr(mm->mmap_base)) {
+ if (preload_add(ti, mm->mmap_base))
+ slb_allocate_user(mm, mm->mmap_base);
+ }
+
+ /* see switch_slb */
+ asm volatile("isync" : : : "memory");
+
+ local_irq_enable();
}
+void preload_new_slb_context(unsigned long start, unsigned long sp)
+{
+ struct thread_info *ti = current_thread_info();
+ struct mm_struct *mm = current->mm;
+ unsigned long heap = mm->start_brk;
+
+ WARN_ON(irqs_disabled());
+
+ /* see above */
+ if (ti->slb_preload_nr + 3 > SLB_PRELOAD_NR)
+ return;
+
+ hard_irq_disable();
+
+ /* Userspace entry address. */
+ if (!is_kernel_addr(start)) {
+ if (preload_add(ti, start))
+ slb_allocate_user(mm, start);
+ }
+
+ /* Top of stack, grows down. */
+ if (!is_kernel_addr(sp)) {
+ if (preload_add(ti, sp))
+ slb_allocate_user(mm, sp);
+ }
+
+ /* Bottom of heap, grows up. */
+ if (heap && !is_kernel_addr(heap)) {
+ if (preload_add(ti, heap))
+ slb_allocate_user(mm, heap);
+ }
+
+ /* see switch_slb */
+ asm volatile("isync" : : : "memory");
+
+ local_irq_enable();
+}
+
+
/* Flush all user entries from the segment table of the current processor. */
void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
{
- unsigned long offset;
- unsigned long slbie_data = 0;
- unsigned long pc = KSTK_EIP(tsk);
- unsigned long stack = KSTK_ESP(tsk);
- unsigned long exec_base;
+ struct thread_info *ti = task_thread_info(tsk);
+ unsigned char i;
/*
* We need interrupts hard-disabled here, not just soft-disabled,
@@ -238,91 +421,107 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
* which would update the slb_cache/slb_cache_ptr fields in the PACA.
*/
hard_irq_disable();
- offset = get_paca()->slb_cache_ptr;
- if (!mmu_has_feature(MMU_FTR_NO_SLBIE_B) &&
- offset <= SLB_CACHE_ENTRIES) {
- int i;
- asm volatile("isync" : : : "memory");
- for (i = 0; i < offset; i++) {
- slbie_data = (unsigned long)get_paca()->slb_cache[i]
- << SID_SHIFT; /* EA */
- slbie_data |= user_segment_size(slbie_data)
- << SLBIE_SSIZE_SHIFT;
- slbie_data |= SLBIE_C; /* C set for user addresses */
- asm volatile("slbie %0" : : "r" (slbie_data));
- }
- asm volatile("isync" : : : "memory");
+ asm volatile("isync" : : : "memory");
+ if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+ /*
+ * SLBIA IH=3 invalidates all Class=1 SLBEs and their
+ * associated lookaside structures, which matches what
+ * switch_slb wants. So ARCH_300 does not use the slb
+ * cache.
+ */
+ asm volatile(PPC_SLBIA(3));
} else {
- __slb_flush_and_rebolt();
- }
+ unsigned long offset = get_paca()->slb_cache_ptr;
+
+ if (!mmu_has_feature(MMU_FTR_NO_SLBIE_B) &&
+ offset <= SLB_CACHE_ENTRIES) {
+ unsigned long slbie_data = 0;
+
+ for (i = 0; i < offset; i++) {
+ unsigned long ea;
+
+ ea = (unsigned long)
+ get_paca()->slb_cache[i] << SID_SHIFT;
+ /*
+ * Could assert_slb_exists here, but hypervisor
+ * or machine check could have come in and
+ * removed the entry at this point.
+ */
+
+ slbie_data = ea;
+ slbie_data |= user_segment_size(slbie_data)
+ << SLBIE_SSIZE_SHIFT;
+ slbie_data |= SLBIE_C; /* user slbs have C=1 */
+ asm volatile("slbie %0" : : "r" (slbie_data));
+ }
+
+ /* Workaround POWER5 < DD2.1 issue */
+ if (!cpu_has_feature(CPU_FTR_ARCH_207S) && offset == 1)
+ asm volatile("slbie %0" : : "r" (slbie_data));
+
+ } else {
+ struct slb_shadow *p = get_slb_shadow();
+ unsigned long ksp_esid_data =
+ be64_to_cpu(p->save_area[KSTACK_INDEX].esid);
+ unsigned long ksp_vsid_data =
+ be64_to_cpu(p->save_area[KSTACK_INDEX].vsid);
+
+ asm volatile(PPC_SLBIA(1) "\n"
+ "slbmte %0,%1\n"
+ "isync"
+ :: "r"(ksp_vsid_data),
+ "r"(ksp_esid_data));
+
+ get_paca()->slb_kern_bitmap = (1U << SLB_NUM_BOLTED) - 1;
+ }
- /* Workaround POWER5 < DD2.1 issue */
- if (offset == 1 || offset > SLB_CACHE_ENTRIES)
- asm volatile("slbie %0" : : "r" (slbie_data));
+ get_paca()->slb_cache_ptr = 0;
+ }
+ get_paca()->slb_used_bitmap = get_paca()->slb_kern_bitmap;
- get_paca()->slb_cache_ptr = 0;
copy_mm_to_paca(mm);
/*
- * preload some userspace segments into the SLB.
- * Almost all 32 and 64bit PowerPC executables are linked at
- * 0x10000000 so it makes sense to preload this segment.
+ * We gradually age out SLBs after a number of context switches to
+ * reduce reload overhead of unused entries (like we do with FP/VEC
+ * reload). Each time we wrap 256 switches, take an entry out of the
+ * SLB preload cache.
*/
- exec_base = 0x10000000;
-
- if (is_kernel_addr(pc) || is_kernel_addr(stack) ||
- is_kernel_addr(exec_base))
- return;
+ tsk->thread.load_slb++;
+ if (!tsk->thread.load_slb) {
+ unsigned long pc = KSTK_EIP(tsk);
- slb_allocate(pc);
+ preload_age(ti);
+ preload_add(ti, pc);
+ }
- if (!esids_match(pc, stack))
- slb_allocate(stack);
+ for (i = 0; i < ti->slb_preload_nr; i++) {
+ unsigned char idx;
+ unsigned long ea;
- if (!esids_match(pc, exec_base) &&
- !esids_match(stack, exec_base))
- slb_allocate(exec_base);
-}
+ idx = (ti->slb_preload_tail + i) % SLB_PRELOAD_NR;
+ ea = (unsigned long)ti->slb_preload_esid[idx] << SID_SHIFT;
-static inline void patch_slb_encoding(unsigned int *insn_addr,
- unsigned int immed)
-{
+ slb_allocate_user(mm, ea);
+ }
/*
- * This function patches either an li or a cmpldi instruction with
- * a new immediate value. This relies on the fact that both li
- * (which is actually addi) and cmpldi both take a 16-bit immediate
- * value, and it is situated in the same location in the instruction,
- * ie. bits 16-31 (Big endian bit order) or the lower 16 bits.
- * The signedness of the immediate operand differs between the two
- * instructions however this code is only ever patching a small value,
- * much less than 1 << 15, so we can get away with it.
- * To patch the value we read the existing instruction, clear the
- * immediate value, and or in our new value, then write the instruction
- * back.
+ * Synchronize slbmte preloads with possible subsequent user memory
+ * address accesses by the kernel (user mode won't happen until
+ * rfid, which is safe).
*/
- unsigned int insn = (*insn_addr & 0xffff0000) | immed;
- patch_instruction(insn_addr, insn);
+ asm volatile("isync" : : : "memory");
}
-extern u32 slb_miss_kernel_load_linear[];
-extern u32 slb_miss_kernel_load_io[];
-extern u32 slb_compare_rr_to_size[];
-extern u32 slb_miss_kernel_load_vmemmap[];
-
void slb_set_size(u16 size)
{
- if (mmu_slb_size == size)
- return;
-
mmu_slb_size = size;
- patch_slb_encoding(slb_compare_rr_to_size, mmu_slb_size);
}
void slb_initialize(void)
{
unsigned long linear_llp, vmalloc_llp, io_llp;
- unsigned long lflags, vflags;
+ unsigned long lflags;
static int slb_encoding_inited;
#ifdef CONFIG_SPARSEMEM_VMEMMAP
unsigned long vmemmap_llp;
@@ -338,34 +537,24 @@ void slb_initialize(void)
#endif
if (!slb_encoding_inited) {
slb_encoding_inited = 1;
- patch_slb_encoding(slb_miss_kernel_load_linear,
- SLB_VSID_KERNEL | linear_llp);
- patch_slb_encoding(slb_miss_kernel_load_io,
- SLB_VSID_KERNEL | io_llp);
- patch_slb_encoding(slb_compare_rr_to_size,
- mmu_slb_size);
-
pr_devel("SLB: linear LLP = %04lx\n", linear_llp);
pr_devel("SLB: io LLP = %04lx\n", io_llp);
-
#ifdef CONFIG_SPARSEMEM_VMEMMAP
- patch_slb_encoding(slb_miss_kernel_load_vmemmap,
- SLB_VSID_KERNEL | vmemmap_llp);
pr_devel("SLB: vmemmap LLP = %04lx\n", vmemmap_llp);
#endif
}
- get_paca()->stab_rr = SLB_NUM_BOLTED;
+ get_paca()->stab_rr = SLB_NUM_BOLTED - 1;
+ get_paca()->slb_kern_bitmap = (1U << SLB_NUM_BOLTED) - 1;
+ get_paca()->slb_used_bitmap = get_paca()->slb_kern_bitmap;
lflags = SLB_VSID_KERNEL | linear_llp;
- vflags = SLB_VSID_KERNEL | vmalloc_llp;
/* Invalidate the entire SLB (even entry 0) & all the ERATS */
asm volatile("isync":::"memory");
asm volatile("slbmte %0,%0"::"r" (0) : "memory");
asm volatile("isync; slbia; isync":::"memory");
create_shadowed_slbe(PAGE_OFFSET, mmu_kernel_ssize, lflags, LINEAR_INDEX);
- create_shadowed_slbe(VMALLOC_START, mmu_kernel_ssize, vflags, VMALLOC_INDEX);
/* For the boot cpu, we're running on the stack in init_thread_union,
* which is in the first segment of the linear mapping, and also
@@ -381,122 +570,259 @@ void slb_initialize(void)
asm volatile("isync":::"memory");
}
-static void insert_slb_entry(unsigned long vsid, unsigned long ea,
- int bpsize, int ssize)
+static void slb_cache_update(unsigned long esid_data)
{
- unsigned long flags, vsid_data, esid_data;
- enum slb_index index;
int slb_cache_index;
- /*
- * We are irq disabled, hence should be safe to access PACA.
- */
- VM_WARN_ON(!irqs_disabled());
-
- /*
- * We can't take a PMU exception in the following code, so hard
- * disable interrupts.
- */
- hard_irq_disable();
-
- index = get_paca()->stab_rr;
-
- /*
- * simple round-robin replacement of slb starting at SLB_NUM_BOLTED.
- */
- if (index < (mmu_slb_size - 1))
- index++;
- else
- index = SLB_NUM_BOLTED;
-
- get_paca()->stab_rr = index;
-
- flags = SLB_VSID_USER | mmu_psize_defs[bpsize].sllp;
- vsid_data = (vsid << slb_vsid_shift(ssize)) | flags |
- ((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
- esid_data = mk_esid_data(ea, ssize, index);
-
- /*
- * No need for an isync before or after this slbmte. The exception
- * we enter with and the rfid we exit with are context synchronizing.
- * Also we only handle user segments here.
- */
- asm volatile("slbmte %0, %1" : : "r" (vsid_data), "r" (esid_data)
- : "memory");
+ if (cpu_has_feature(CPU_FTR_ARCH_300))
+ return; /* ISAv3.0B and later does not use slb_cache */
/*
* Now update slb cache entries
*/
- slb_cache_index = get_paca()->slb_cache_ptr;
+ slb_cache_index = local_paca->slb_cache_ptr;
if (slb_cache_index < SLB_CACHE_ENTRIES) {
/*
* We have space in slb cache for optimized switch_slb().
* Top 36 bits from esid_data as per ISA
*/
- get_paca()->slb_cache[slb_cache_index++] = esid_data >> 28;
- get_paca()->slb_cache_ptr++;
+ local_paca->slb_cache[slb_cache_index++] = esid_data >> 28;
+ local_paca->slb_cache_ptr++;
} else {
/*
* Our cache is full and the current cache content strictly
* doesn't indicate the active SLB conents. Bump the ptr
* so that switch_slb() will ignore the cache.
*/
- get_paca()->slb_cache_ptr = SLB_CACHE_ENTRIES + 1;
+ local_paca->slb_cache_ptr = SLB_CACHE_ENTRIES + 1;
}
}
-static void handle_multi_context_slb_miss(int context_id, unsigned long ea)
+static enum slb_index alloc_slb_index(bool kernel)
{
- struct mm_struct *mm = current->mm;
- unsigned long vsid;
- int bpsize;
+ enum slb_index index;
/*
- * We are always above 1TB, hence use high user segment size.
+ * The allocation bitmaps can become out of synch with the SLB
+ * when the _switch code does slbie when bolting a new stack
+ * segment and it must not be anywhere else in the SLB. This leaves
+ * a kernel allocated entry that is unused in the SLB. With very
+ * large systems or small segment sizes, the bitmaps could slowly
+ * fill with these entries. They will eventually be cleared out
+ * by the round robin allocator in that case, so it's probably not
+ * worth accounting for.
*/
- vsid = get_vsid(context_id, ea, mmu_highuser_ssize);
- bpsize = get_slice_psize(mm, ea);
- insert_slb_entry(vsid, ea, bpsize, mmu_highuser_ssize);
+
+ /*
+ * SLBs beyond 32 entries are allocated with stab_rr only
+ * POWER7/8/9 have 32 SLB entries, this could be expanded if a
+ * future CPU has more.
+ */
+ if (local_paca->slb_used_bitmap != U32_MAX) {
+ index = ffz(local_paca->slb_used_bitmap);
+ local_paca->slb_used_bitmap |= 1U << index;
+ if (kernel)
+ local_paca->slb_kern_bitmap |= 1U << index;
+ } else {
+ /* round-robin replacement of slb starting at SLB_NUM_BOLTED. */
+ index = local_paca->stab_rr;
+ if (index < (mmu_slb_size - 1))
+ index++;
+ else
+ index = SLB_NUM_BOLTED;
+ local_paca->stab_rr = index;
+ if (index < 32) {
+ if (kernel)
+ local_paca->slb_kern_bitmap |= 1U << index;
+ else
+ local_paca->slb_kern_bitmap &= ~(1U << index);
+ }
+ }
+ BUG_ON(index < SLB_NUM_BOLTED);
+
+ return index;
}
-void slb_miss_large_addr(struct pt_regs *regs)
+static long slb_insert_entry(unsigned long ea, unsigned long context,
+ unsigned long flags, int ssize, bool kernel)
{
- enum ctx_state prev_state = exception_enter();
- unsigned long ea = regs->dar;
- int context;
+ unsigned long vsid;
+ unsigned long vsid_data, esid_data;
+ enum slb_index index;
- if (REGION_ID(ea) != USER_REGION_ID)
- goto slb_bad_addr;
+ vsid = get_vsid(context, ea, ssize);
+ if (!vsid)
+ return -EFAULT;
/*
- * Are we beyound what the page table layout supports ?
+ * There must not be a kernel SLB fault in alloc_slb_index or before
+ * slbmte here or the allocation bitmaps could get out of whack with
+ * the SLB.
+ *
+ * User SLB faults or preloads take this path which might get inlined
+ * into the caller, so add compiler barriers here to ensure unsafe
+ * memory accesses do not come between.
*/
- if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
- goto slb_bad_addr;
+ barrier();
- /* Lower address should have been handled by asm code */
- if (ea < (1UL << MAX_EA_BITS_PER_CONTEXT))
- goto slb_bad_addr;
+ index = alloc_slb_index(kernel);
+
+ vsid_data = __mk_vsid_data(vsid, ssize, flags);
+ esid_data = mk_esid_data(ea, ssize, index);
+
+ /*
+ * No need for an isync before or after this slbmte. The exception
+ * we enter with and the rfid we exit with are context synchronizing.
+ * User preloads should add isync afterwards in case the kernel
+ * accesses user memory before it returns to userspace with rfid.
+ */
+ assert_slb_notexists(ea);
+ asm volatile("slbmte %0, %1" : : "r" (vsid_data), "r" (esid_data));
+
+ barrier();
+
+ if (!kernel)
+ slb_cache_update(esid_data);
+
+ return 0;
+}
+
+static long slb_allocate_kernel(unsigned long ea, unsigned long id)
+{
+ unsigned long context;
+ unsigned long flags;
+ int ssize;
+
+ if (id == KERNEL_REGION_ID) {
+
+ /* We only support upto MAX_PHYSMEM_BITS */
+ if ((ea & ~REGION_MASK) > (1UL << MAX_PHYSMEM_BITS))
+ return -EFAULT;
+
+ flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp;
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+ } else if (id == VMEMMAP_REGION_ID) {
+
+ if ((ea & ~REGION_MASK) >= (1ULL << MAX_EA_BITS_PER_CONTEXT))
+ return -EFAULT;
+
+ flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmemmap_psize].sllp;
+#endif
+ } else if (id == VMALLOC_REGION_ID) {
+
+ if ((ea & ~REGION_MASK) >= (1ULL << MAX_EA_BITS_PER_CONTEXT))
+ return -EFAULT;
+
+ if (ea < H_VMALLOC_END)
+ flags = get_paca()->vmalloc_sllp;
+ else
+ flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_io_psize].sllp;
+ } else {
+ return -EFAULT;
+ }
+
+ ssize = MMU_SEGSIZE_1T;
+ if (!mmu_has_feature(MMU_FTR_1T_SEGMENT))
+ ssize = MMU_SEGSIZE_256M;
+
+ context = get_kernel_context(ea);
+ return slb_insert_entry(ea, context, flags, ssize, true);
+}
+
+static long slb_allocate_user(struct mm_struct *mm, unsigned long ea)
+{
+ unsigned long context;
+ unsigned long flags;
+ int bpsize;
+ int ssize;
/*
* consider this as bad access if we take a SLB miss
* on an address above addr limit.
*/
- if (ea >= current->mm->context.slb_addr_limit)
- goto slb_bad_addr;
+ if (ea >= mm->context.slb_addr_limit)
+ return -EFAULT;
- context = get_ea_context(&current->mm->context, ea);
+ context = get_user_context(&mm->context, ea);
if (!context)
- goto slb_bad_addr;
+ return -EFAULT;
+
+ if (unlikely(ea >= H_PGTABLE_RANGE)) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
- handle_multi_context_slb_miss(context, ea);
- exception_exit(prev_state);
- return;
+ ssize = user_segment_size(ea);
-slb_bad_addr:
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_BNDERR, ea);
- else
- bad_page_fault(regs, ea, SIGSEGV);
- exception_exit(prev_state);
+ bpsize = get_slice_psize(mm, ea);
+ flags = SLB_VSID_USER | mmu_psize_defs[bpsize].sllp;
+
+ return slb_insert_entry(ea, context, flags, ssize, false);
+}
+
+long do_slb_fault(struct pt_regs *regs, unsigned long ea)
+{
+ unsigned long id = REGION_ID(ea);
+
+ /* IRQs are not reconciled here, so can't check irqs_disabled */
+ VM_WARN_ON(mfmsr() & MSR_EE);
+
+ if (unlikely(!(regs->msr & MSR_RI)))
+ return -EINVAL;
+
+ /*
+ * SLB kernel faults must be very careful not to touch anything
+ * that is not bolted. E.g., PACA and global variables are okay,
+ * mm->context stuff is not.
+ *
+ * SLB user faults can access all of kernel memory, but must be
+ * careful not to touch things like IRQ state because it is not
+ * "reconciled" here. The difficulty is that we must use
+ * fast_exception_return to return from kernel SLB faults without
+ * looking at possible non-bolted memory. We could test user vs
+ * kernel faults in the interrupt handler asm and do a full fault,
+ * reconcile, ret_from_except for user faults which would make them
+ * first class kernel code. But for performance it's probably nicer
+ * if they go via fast_exception_return too.
+ */
+ if (id >= KERNEL_REGION_ID) {
+ long err;
+#ifdef CONFIG_DEBUG_VM
+ /* Catch recursive kernel SLB faults. */
+ BUG_ON(local_paca->in_kernel_slb_handler);
+ local_paca->in_kernel_slb_handler = 1;
+#endif
+ err = slb_allocate_kernel(ea, id);
+#ifdef CONFIG_DEBUG_VM
+ local_paca->in_kernel_slb_handler = 0;
+#endif
+ return err;
+ } else {
+ struct mm_struct *mm = current->mm;
+ long err;
+
+ if (unlikely(!mm))
+ return -EFAULT;
+
+ err = slb_allocate_user(mm, ea);
+ if (!err)
+ preload_add(current_thread_info(), ea);
+
+ return err;
+ }
+}
+
+void do_bad_slb_fault(struct pt_regs *regs, unsigned long ea, long err)
+{
+ if (err == -EFAULT) {
+ if (user_mode(regs))
+ _exception(SIGSEGV, regs, SEGV_BNDERR, ea);
+ else
+ bad_page_fault(regs, ea, SIGSEGV);
+ } else if (err == -EINVAL) {
+ unrecoverable_exception(regs);
+ } else {
+ BUG();
+ }
}