Changes in kernel/arch/mips32/src/mm/tlb.c [1dbc43f:b2fa1204] in mainline

File:

• kernel/arch/mips32/src/mm/tlb.c (modified) (21 diffs)

kernel/arch/mips32/src/mm/tlb.c

@@ -43 +43 @@
 #include <synch/mutex.h>
 #include <print.h>
+#include <log.h>
 #include <debug.h>
 #include <align.h>
@@ -48 +49 @@
 #include <symtab.h>
 
-static pte_t *find_mapping_and_check(uintptr_t, int, istate_t *);
+#define PFN_SHIFT  12
+#define VPN_SHIFT  12
+
+#define ADDR2HI_VPN(a)   ((a) >> VPN_SHIFT)
+#define ADDR2HI_VPN2(a)  (ADDR2HI_VPN((a)) >> 1)
+
+#define HI_VPN2ADDR(vpn)    ((vpn) << VPN_SHIFT)
+#define HI_VPN22ADDR(vpn2)  (HI_VPN2ADDR(vpn2) << 1)
+
+#define LO_PFN2ADDR(pfn)  ((pfn) << PFN_SHIFT)
+
+#define BANK_SELECT_BIT(a)  (((a) >> PAGE_WIDTH) & 1)
 
 /** Initialize TLB.
@@ -84 +96 @@
 {
         entry_lo_t lo;
-        entry_hi_t hi;
-        asid_t asid;
         uintptr_t badvaddr;
         pte_t *pte;
         
         badvaddr = cp0_badvaddr_read();
-        asid = AS->asid;
-        
-        pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate);
-        if (pte) {
+
+        pte = page_mapping_find(AS, badvaddr, true);
+        if (pte && pte->p) {
                 /*
                  * Record access to PTE.
@@ -99 +108 @@
                 pte->a = 1;
 
-                tlb_prepare_entry_hi(&hi, asid, badvaddr);
                 tlb_prepare_entry_lo(&lo, pte->g, pte->p, pte->d,
                     pte->cacheable, pte->pfn);
@@ -106 +114 @@
                  * New entry is to be inserted into TLB
                  */
-                cp0_entry_hi_write(hi.value);
-                if ((badvaddr / PAGE_SIZE) % 2 == 0) {
+                if (BANK_SELECT_BIT(badvaddr) == 0) {
                         cp0_entry_lo0_write(lo.value);
                         cp0_entry_lo1_write(0);
@@ -116 +123 @@
                 cp0_pagemask_write(TLB_PAGE_MASK_16K);
                 tlbwr();
-        }
+                return;
+        }
+
+        (void) as_page_fault(badvaddr, PF_ACCESS_READ, istate);
 }
 
@@ -125 +135 @@
 void tlb_invalid(istate_t *istate)
 {
+        entry_lo_t lo;
         tlb_index_t index;
         uintptr_t badvaddr;
-        entry_lo_t lo;
-        entry_hi_t hi;
         pte_t *pte;
-
-        badvaddr = cp0_badvaddr_read();
 
         /*
          * Locate the faulting entry in TLB.
          */
-        hi.value = cp0_entry_hi_read();
-        tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
-        cp0_entry_hi_write(hi.value);
         tlbp();
         index.value = cp0_index_read();
 
+#if defined(PROCESSOR_4Kc)
+        /*
+         * This can happen on a 4Kc when Status.EXL is 1 and there is a TLB miss.
+         * EXL is 1 when interrupts are disabled. The combination of a TLB miss
+         * and disabled interrupts is possible in copy_to/from_uspace().
+         */
+        if (index.p) {
+                tlb_refill(istate);
+                return;
+        }
+#endif
+
         ASSERT(!index.p);
 
-        pte = find_mapping_and_check(badvaddr, PF_ACCESS_READ, istate);
-        if (pte) {
+        badvaddr = cp0_badvaddr_read();
+
+        pte = page_mapping_find(AS, badvaddr, true);
+        if (pte && pte->p) {
                 /*
                  * Read the faulting TLB entry.
@@ -162 +180 @@
                  * The entry is to be updated in TLB.
                  */
-                if ((badvaddr / PAGE_SIZE) % 2 == 0)
+                if (BANK_SELECT_BIT(badvaddr) == 0)
                         cp0_entry_lo0_write(lo.value);
                 else
                         cp0_entry_lo1_write(lo.value);
-                cp0_pagemask_write(TLB_PAGE_MASK_16K);
                 tlbwi();
-        }
+                return;
+        }
+
+        (void) as_page_fault(badvaddr, PF_ACCESS_READ, istate);
 }
 
@@ -177 +197 @@
 void tlb_modified(istate_t *istate)
 {
+        entry_lo_t lo;
         tlb_index_t index;
         uintptr_t badvaddr;
-        entry_lo_t lo;
-        entry_hi_t hi;
         pte_t *pte;
 
@@ -188 +207 @@
          * Locate the faulting entry in TLB.
          */
-        hi.value = cp0_entry_hi_read();
-        tlb_prepare_entry_hi(&hi, hi.asid, badvaddr);
-        cp0_entry_hi_write(hi.value);
         tlbp();
         index.value = cp0_index_read();
 
         /*
-         * Fail if the entry is not in TLB.
+         * Emit warning if the entry is not in TLB.
+         *
+         * We do not assert on this because this could be a manifestation of
+         * an emulator bug, such as QEMU Bug #1128935:
+         * https://bugs.launchpad.net/qemu/+bug/1128935  
          */
-        ASSERT(!index.p);
-
-        pte = find_mapping_and_check(badvaddr, PF_ACCESS_WRITE, istate);
-        if (pte) {
+        if (index.p) {
+                log(LF_ARCH, LVL_WARN, "%s: TLBP failed in exception handler (badvaddr=%#"
+                    PRIxn ", ASID=%d).\n", __func__, badvaddr,
+                    AS ? AS->asid : -1);
+                return;
+        }
+
+        pte = page_mapping_find(AS, badvaddr, true);
+        if (pte && pte->p && pte->w) {
                 /*
                  * Read the faulting TLB entry.
@@ -218 +243 @@
                  * The entry is to be updated in TLB.
                  */
-                if ((badvaddr / PAGE_SIZE) % 2 == 0)
+                if (BANK_SELECT_BIT(badvaddr) == 0)
                         cp0_entry_lo0_write(lo.value);
                 else
                         cp0_entry_lo1_write(lo.value);
-                cp0_pagemask_write(TLB_PAGE_MASK_16K);
                 tlbwi();
-        }
-}
-
-/** Try to find PTE for faulting address.
- *
- * @param badvaddr      Faulting virtual address.
- * @param access        Access mode that caused the fault.
- * @param istate        Pointer to interrupted state.
- *
- * @return              PTE on success, NULL otherwise.
- */
-pte_t *find_mapping_and_check(uintptr_t badvaddr, int access, istate_t *istate)
-{
-        entry_hi_t hi;
-        pte_t *pte;
-
-        hi.value = cp0_entry_hi_read();
-
-        ASSERT(hi.asid == AS->asid);
-
-        /*
-         * Check if the mapping exists in page tables.
-         */     
-        pte = page_mapping_find(AS, badvaddr, true);
-        if (pte && pte->p && (pte->w || access != PF_ACCESS_WRITE)) {
-                /*
-                 * Mapping found in page tables.
-                 * Immediately succeed.
-                 */
-                return pte;
-        }
-
-        /*
-         * Mapping not found in page tables.
-         * Resort to higher-level page fault handler.
-         */
-        if (as_page_fault(badvaddr, access, istate) == AS_PF_OK) {
-                pte = page_mapping_find(AS, badvaddr, true);
-                ASSERT(pte && pte->p);
-                ASSERT(pte->w || access != PF_ACCESS_WRITE);
-                return pte;
-        }
-
-        return NULL;
+                return;
+        }
+
+        (void) as_page_fault(badvaddr, PF_ACCESS_WRITE, istate);
 }
 
@@ -284 +268 @@
 void tlb_prepare_entry_hi(entry_hi_t *hi, asid_t asid, uintptr_t addr)
 {
-        hi->value = ALIGN_DOWN(addr, PAGE_SIZE * 2);
+        hi->value = 0;
+        hi->vpn2 = ADDR2HI_VPN2(ALIGN_DOWN(addr, PAGE_SIZE));
         hi->asid = asid;
 }
@@ -291 +276 @@
 void tlb_print(void)
 {
-        page_mask_t mask;
-        entry_lo_t lo0, lo1;
+        page_mask_t mask, mask_save;
+        entry_lo_t lo0, lo0_save, lo1, lo1_save;
         entry_hi_t hi, hi_save;
         unsigned int i;
 
         hi_save.value = cp0_entry_hi_read();
-        
-        printf("[nr] [asid] [vpn2] [mask] [gvdc] [pfn ]\n");
+        lo0_save.value = cp0_entry_lo0_read();
+        lo1_save.value = cp0_entry_lo1_read();
+        mask_save.value = cp0_pagemask_read();
+        
+        printf("[nr] [asid] [vpn2    ] [mask] [gvdc] [pfn     ]\n");
         
         for (i = 0; i < TLB_ENTRY_COUNT; i++) {
@@ -309 +297 @@
                 lo1.value = cp0_entry_lo1_read();
                 
-                printf("%-4u %-6u %#6x %#6x  %1u%1u%1u%1u  %#6x\n",
-                    i, hi.asid, hi.vpn2, mask.mask,
-                    lo0.g, lo0.v, lo0.d, lo0.c, lo0.pfn);
-                printf("                           %1u%1u%1u%1u  %#6x\n",
-                    lo1.g, lo1.v, lo1.d, lo1.c, lo1.pfn);
+                printf("%-4u %-6u %0#10x %-#6x  %1u%1u%1u%1u  %0#10x\n",
+                    i, hi.asid, HI_VPN22ADDR(hi.vpn2), mask.mask,
+                    lo0.g, lo0.v, lo0.d, lo0.c, LO_PFN2ADDR(lo0.pfn));
+                printf("                               %1u%1u%1u%1u  %0#10x\n",
+                    lo1.g, lo1.v, lo1.d, lo1.c, LO_PFN2ADDR(lo1.pfn));
         }
         
         cp0_entry_hi_write(hi_save.value);
+        cp0_entry_lo0_write(lo0_save.value);
+        cp0_entry_lo1_write(lo1_save.value);
+        cp0_pagemask_write(mask_save.value);
 }
 
@@ -322 +313 @@
 void tlb_invalidate_all(void)
 {
-        ipl_t ipl;
         entry_lo_t lo0, lo1;
         entry_hi_t hi_save;
         int i;
 
+        ASSERT(interrupts_disabled());
+
         hi_save.value = cp0_entry_hi_read();
-        ipl = interrupts_disable();
 
         for (i = TLB_WIRED; i < TLB_ENTRY_COUNT; i++) {
@@ -346 +337 @@
         }
         
-        interrupts_restore(ipl);
         cp0_entry_hi_write(hi_save.value);
 }
@@ -356 +346 @@
 void tlb_invalidate_asid(asid_t asid)
 {
-        ipl_t ipl;
         entry_lo_t lo0, lo1;
         entry_hi_t hi, hi_save;
         int i;
 
+        ASSERT(interrupts_disabled());
         ASSERT(asid != ASID_INVALID);
 
         hi_save.value = cp0_entry_hi_read();
-        ipl = interrupts_disable();
         
         for (i = 0; i < TLB_ENTRY_COUNT; i++) {
@@ -386 +375 @@
         }
         
-        interrupts_restore(ipl);
         cp0_entry_hi_write(hi_save.value);
 }
@@ -400 +388 @@
 {
         unsigned int i;
-        ipl_t ipl;
         entry_lo_t lo0, lo1;
         entry_hi_t hi, hi_save;
         tlb_index_t index;
+
+        ASSERT(interrupts_disabled());
         
         if (asid == ASID_INVALID)
@@ -409 +398 @@
 
         hi_save.value = cp0_entry_hi_read();
-        ipl = interrupts_disable();
 
         for (i = 0; i < cnt + 1; i += 2) {
-                hi.value = 0;
                 tlb_prepare_entry_hi(&hi, asid, page + i * PAGE_SIZE);
                 cp0_entry_hi_write(hi.value);
@@ -439 +426 @@
         }
         
-        interrupts_restore(ipl);
         cp0_entry_hi_write(hi_save.value);
 }