powerpc/mm: Add addr_limit to mm_context and use it to derive max slice index

In the followup patch, we will increase the slice array size to handle
512TB range, but will limit the max addr to 128TB. Avoid doing
unnecessary computation and avoid doing slice mask related operation
above address limit.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index c93450bf306fed9340bc5b3f767d065ed39b49d9..5961b0d65a7924519ac1e052652c8c62c71ba55a 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -597,7 +597,8 @@ extern void slb_set_size(u16 size);
 #define USER_VSID_RANGE        (1UL << (ESID_BITS + SID_SHIFT))
 
 /* 4 bits per slice and we have one slice per 1TB */
-#define SLICE_ARRAY_SIZE  (H_PGTABLE_RANGE >> 41)
+#define SLICE_ARRAY_SIZE       (H_PGTABLE_RANGE >> 41)
+#define TASK_SLICE_ARRAY_SZ(x) ((x)->context.addr_limit >> 41)
 
 #ifndef __ASSEMBLY__
 

diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index cce434e7de068484a3f8dfc08a5d0be422f513ca..c4b865112d2484709bf8b17b4ba3c830fc25232a 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -82,6 +82,7 @@ typedef struct {
 #ifdef CONFIG_PPC_MM_SLICES
        u64 low_slices_psize;   /* SLB page size encodings */
        unsigned char high_slices_psize[SLICE_ARRAY_SIZE];
+       unsigned long addr_limit;
 #else
        u16 sllp;               /* SLB page size encoding */
 #endif

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index e2cf745a4b943b9874034316514b9f91f6ea24e6..a2c7a6456ee6471ffa9d452e0cc75bb38052fc8d 100644 (file)
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -253,9 +253,10 @@ void copy_mm_to_paca(struct mm_struct *mm)
 
        get_paca()->mm_ctx_id = context->id;
 #ifdef CONFIG_PPC_MM_SLICES
+       VM_BUG_ON(!mm->context.addr_limit);
        get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
        memcpy(&get_paca()->mm_ctx_high_slices_psize,
-              &context->high_slices_psize, SLICE_ARRAY_SIZE);
+              &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
 #else /* CONFIG_PPC_MM_SLICES */
        get_paca()->mm_ctx_user_psize = context->user_psize;
        get_paca()->mm_ctx_sllp = context->sllp;

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 4697da89513392ea0961b3d7d9cc001270911741..a79db6b6346655ecbb97d5b8c7fd8307e92dcbab 100644 (file)
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -920,6 +920,15 @@ void __init setup_arch(char **cmdline_p)
        init_mm.end_code = (unsigned long) _etext;
        init_mm.end_data = (unsigned long) _edata;
        init_mm.brk = klimit;
+
+#ifdef CONFIG_PPC_MM_SLICES
+#ifdef CONFIG_PPC64
+       init_mm.context.addr_limit = TASK_SIZE_USER64;
+#else
+#error "context.addr_limit not initialized."
+#endif
+#endif
+
 #ifdef CONFIG_PPC_64K_PAGES
        init_mm.context.pte_frag = NULL;
 #endif

diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index e5fde156e11dd8688255979b578126d2a7524955..fd0bc6db2dcde9457e0d878754e60a31532c4c50 100644 (file)
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -78,6 +78,13 @@ static int hash__init_new_context(struct mm_struct *mm)
        if (index < 0)
                return index;
 
+       /*
+        * We do switch_slb() early in fork, even before we setup the
+        * mm->context.addr_limit. Default to max task size so that we copy the
+        * default values to paca which will help us to handle slb miss early.
+        */
+       mm->context.addr_limit = TASK_SIZE_USER64;
+
        /*
         * The old code would re-promote on fork, we don't do that when using
         * slices as it could cause problem promoting slices that have been

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 95e5a20b1b6a072ea247f874e7c95ef526b75811..ded96edac8175e4144bfa5e5d5978ab5ab8909d8 100644 (file)
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -136,7 +136,7 @@ static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret)
        if (mm->task_size <= SLICE_LOW_TOP)
                return;
 
-       for (i = 0; i < SLICE_NUM_HIGH; i++)
+       for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++)
                if (!slice_high_has_vma(mm, i))
                        __set_bit(i, ret->high_slices);
 }
@@ -157,7 +157,7 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
                        ret->low_slices |= 1u << i;
 
        hpsizes = mm->context.high_slices_psize;
-       for (i = 0; i < SLICE_NUM_HIGH; i++) {
+       for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++) {
                mask_index = i & 0x1;
                index = i >> 1;
                if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
@@ -165,15 +165,17 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
        }
 }
 
-static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
+static int slice_check_fit(struct mm_struct *mm,
+                          struct slice_mask mask, struct slice_mask available)
 {
        DECLARE_BITMAP(result, SLICE_NUM_HIGH);
+       unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.addr_limit);
 
        bitmap_and(result, mask.high_slices,
-                  available.high_slices, SLICE_NUM_HIGH);
+                  available.high_slices, slice_count);
 
        return (mask.low_slices & available.low_slices) == mask.low_slices &&
-               bitmap_equal(result, mask.high_slices, SLICE_NUM_HIGH);
+               bitmap_equal(result, mask.high_slices, slice_count);
 }
 
 static void slice_flush_segments(void *parm)
@@ -217,7 +219,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
        mm->context.low_slices_psize = lpsizes;
 
        hpsizes = mm->context.high_slices_psize;
-       for (i = 0; i < SLICE_NUM_HIGH; i++) {
+       for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++) {
                mask_index = i & 0x1;
                index = i >> 1;
                if (test_bit(i, mask.high_slices))
@@ -484,7 +486,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
                /* Check if we fit in the good mask. If we do, we just return,
                 * nothing else to do
                 */
-               if (slice_check_fit(mask, good_mask)) {
+               if (slice_check_fit(mm, mask, good_mask)) {
                        slice_dbg(" fits good !\n");
                        return addr;
                }
@@ -509,7 +511,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
        slice_or_mask(&potential_mask, &good_mask);
        slice_print_mask(" potential", potential_mask);
 
-       if ((addr != 0 || fixed) && slice_check_fit(mask, potential_mask)) {
+       if ((addr != 0 || fixed) && slice_check_fit(mm, mask, potential_mask)) {
                slice_dbg(" fits potential !\n");
                goto convert;
        }
@@ -734,6 +736,6 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
        slice_print_mask(" mask", mask);
        slice_print_mask(" available", available);
 #endif
-       return !slice_check_fit(mask, available);
+       return !slice_check_fit(mm, mask, available);
 }
 #endif