diff mbox series

[PULL,76/89] target/riscv: Move leaf pte processing out of level loop

Message ID 20230505010241.21812-77-alistair.francis@wdc.com
State New
Headers show
Series None | expand

Commit Message

Alistair Francis May 5, 2023, 1:02 a.m. UTC 
From: Richard Henderson <richard.henderson@linaro.org>

Move the code that never loops outside of the loop.
Unchain the if-return-else statements.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Tested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230325105429.1142530-21-richard.henderson@linaro.org>
Message-Id: <20230412114333.118895-21-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu_helper.c | 234 ++++++++++++++++++++------------------
 1 file changed, 123 insertions(+), 111 deletions(-)
diff mbox series

Patch

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 7c9f89d4d3..c2d083f029 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -865,6 +865,8 @@  static int get_physical_address(CPURISCVState *env, hwaddr *physical,
     }
 
     int ptshift = (levels - 1) * ptidxbits;
+    target_ulong pte;
+    hwaddr pte_addr;
     int i;
 
 #if !TCG_OVERSIZED_GUEST
@@ -881,7 +883,6 @@  restart:
         }
 
         /* check that physical address of PTE is legal */
-        hwaddr pte_addr;
 
         if (two_stage && first_stage) {
             int vbase_prot;
@@ -913,7 +914,6 @@  restart:
             return TRANSLATE_PMP_FAIL;
         }
 
-        target_ulong pte;
         if (riscv_cpu_mxl(env) == MXL_RV32) {
             pte = address_space_ldl(cs->as, pte_addr, attrs, &res);
         } else {
@@ -938,128 +938,140 @@  restart:
         if (!(pte & PTE_V)) {
             /* Invalid PTE */
             return TRANSLATE_FAIL;
-        } else if (!pbmte && (pte & PTE_PBMT)) {
-            return TRANSLATE_FAIL;
-        } else if (!(pte & (PTE_R | PTE_W | PTE_X))) {
-            /* Inner PTE, continue walking */
-            if (pte & (PTE_D | PTE_A | PTE_U | PTE_ATTR)) {
-                return TRANSLATE_FAIL;
-            }
-            base = ppn << PGSHIFT;
-        } else if ((pte & (PTE_R | PTE_W | PTE_X)) == PTE_W) {
-            /* Reserved leaf PTE flags: PTE_W */
-            return TRANSLATE_FAIL;
-        } else if ((pte & (PTE_R | PTE_W | PTE_X)) == (PTE_W | PTE_X)) {
-            /* Reserved leaf PTE flags: PTE_W + PTE_X */
-            return TRANSLATE_FAIL;
-        } else if ((pte & PTE_U) && ((mode != PRV_U) &&
-                   (!sum || access_type == MMU_INST_FETCH))) {
-            /* User PTE flags when not U mode and mstatus.SUM is not set,
-               or the access type is an instruction fetch */
-            return TRANSLATE_FAIL;
-        } else if (!(pte & PTE_U) && (mode != PRV_S)) {
-            /* Supervisor PTE flags when not S mode */
-            return TRANSLATE_FAIL;
-        } else if (ppn & ((1ULL << ptshift) - 1)) {
-            /* Misaligned PPN */
-            return TRANSLATE_FAIL;
-        } else if (access_type == MMU_DATA_LOAD && !((pte & PTE_R) ||
-                   ((pte & PTE_X) && mxr))) {
-            /* Read access check failed */
-            return TRANSLATE_FAIL;
-        } else if (access_type == MMU_DATA_STORE && !(pte & PTE_W)) {
-            /* Write access check failed */
-            return TRANSLATE_FAIL;
-        } else if (access_type == MMU_INST_FETCH && !(pte & PTE_X)) {
-            /* Fetch access check failed */
+        }
+        if (pte & (PTE_R | PTE_W | PTE_X)) {
+            goto leaf;
+        }
+
+        /* Inner PTE, continue walking */
+        if (pte & (PTE_D | PTE_A | PTE_U | PTE_ATTR)) {
             return TRANSLATE_FAIL;
-        } else {
-            /* if necessary, set accessed and dirty bits. */
-            target_ulong updated_pte = pte | PTE_A |
+        }
+        base = ppn << PGSHIFT;
+    }
+
+    /* No leaf pte at any translation level. */
+    return TRANSLATE_FAIL;
+
+ leaf:
+    if (ppn & ((1ULL << ptshift) - 1)) {
+        /* Misaligned PPN */
+        return TRANSLATE_FAIL;
+    }
+    if (!pbmte && (pte & PTE_PBMT)) {
+        /* Reserved without Svpbmt. */
+        return TRANSLATE_FAIL;
+    }
+    if ((pte & (PTE_R | PTE_W | PTE_X)) == PTE_W) {
+        /* Reserved leaf PTE flags: PTE_W */
+        return TRANSLATE_FAIL;
+    }
+    if ((pte & (PTE_R | PTE_W | PTE_X)) == (PTE_W | PTE_X)) {
+        /* Reserved leaf PTE flags: PTE_W + PTE_X */
+        return TRANSLATE_FAIL;
+    }
+    if ((pte & PTE_U) &&
+        ((mode != PRV_U) && (!sum || access_type == MMU_INST_FETCH))) {
+        /*
+         * User PTE flags when not U mode and mstatus.SUM is not set,
+         * or the access type is an instruction fetch.
+         */
+        return TRANSLATE_FAIL;
+    }
+    if (!(pte & PTE_U) && (mode != PRV_S)) {
+        /* Supervisor PTE flags when not S mode */
+        return TRANSLATE_FAIL;
+    }
+    if (access_type == MMU_DATA_LOAD &&
+        !((pte & PTE_R) || ((pte & PTE_X) && mxr))) {
+        /* Read access check failed */
+        return TRANSLATE_FAIL;
+    }
+    if (access_type == MMU_DATA_STORE && !(pte & PTE_W)) {
+        /* Write access check failed */
+        return TRANSLATE_FAIL;
+    }
+    if (access_type == MMU_INST_FETCH && !(pte & PTE_X)) {
+        /* Fetch access check failed */
+        return TRANSLATE_FAIL;
+    }
+
+    /* If necessary, set accessed and dirty bits. */
+    target_ulong updated_pte = pte | PTE_A |
                 (access_type == MMU_DATA_STORE ? PTE_D : 0);
 
-            /* Page table updates need to be atomic with MTTCG enabled */
-            if (updated_pte != pte) {
-                if (!hade) {
-                    return TRANSLATE_FAIL;
-                }
+    /* Page table updates need to be atomic with MTTCG enabled */
+    if (updated_pte != pte) {
+        if (!hade) {
+            return TRANSLATE_FAIL;
+        }
 
-                /*
-                 * - if accessed or dirty bits need updating, and the PTE is
-                 *   in RAM, then we do so atomically with a compare and swap.
-                 * - if the PTE is in IO space or ROM, then it can't be updated
-                 *   and we return TRANSLATE_FAIL.
-                 * - if the PTE changed by the time we went to update it, then
-                 *   it is no longer valid and we must re-walk the page table.
-                 */
-                MemoryRegion *mr;
-                hwaddr l = sizeof(target_ulong), addr1;
-                mr = address_space_translate(cs->as, pte_addr, &addr1, &l,
-                                             false, MEMTXATTRS_UNSPECIFIED);
-                if (memory_region_is_ram(mr)) {
-                    target_ulong *pte_pa =
-                        qemu_map_ram_ptr(mr->ram_block, addr1);
+        /*
+         * - if accessed or dirty bits need updating, and the PTE is
+         *   in RAM, then we do so atomically with a compare and swap.
+         * - if the PTE is in IO space or ROM, then it can't be updated
+         *   and we return TRANSLATE_FAIL.
+         * - if the PTE changed by the time we went to update it, then
+         *   it is no longer valid and we must re-walk the page table.
+         */
+        MemoryRegion *mr;
+        hwaddr l = sizeof(target_ulong), addr1;
+        mr = address_space_translate(cs->as, pte_addr, &addr1, &l,
+                                     false, MEMTXATTRS_UNSPECIFIED);
+        if (memory_region_is_ram(mr)) {
+            target_ulong *pte_pa = qemu_map_ram_ptr(mr->ram_block, addr1);
 #if TCG_OVERSIZED_GUEST
-                    /*
-                     * MTTCG is not enabled on oversized TCG guests so
-                     * page table updates do not need to be atomic
-                     */
-                    *pte_pa = pte = updated_pte;
+            /*
+             * MTTCG is not enabled on oversized TCG guests so
+             * page table updates do not need to be atomic
+             */
+            *pte_pa = pte = updated_pte;
 #else
-                    target_ulong old_pte =
-                        qatomic_cmpxchg(pte_pa, pte, updated_pte);
-                    if (old_pte != pte) {
-                        goto restart;
-                    } else {
-                        pte = updated_pte;
-                    }
-#endif
-                } else {
-                    /*
-                     * misconfigured PTE in ROM (AD bits are not preset) or
-                     * PTE is in IO space and can't be updated atomically
-                     */
-                    return TRANSLATE_FAIL;
-                }
+            target_ulong old_pte = qatomic_cmpxchg(pte_pa, pte, updated_pte);
+            if (old_pte != pte) {
+                goto restart;
             }
-
+            pte = updated_pte;
+#endif
+        } else {
             /*
-             * for superpage mappings, make a fake leaf PTE for the TLB's
-             * benefit.
+             * Misconfigured PTE in ROM (AD bits are not preset) or
+             * PTE is in IO space and can't be updated atomically.
              */
-            target_ulong vpn = addr >> PGSHIFT;
-
-            if (riscv_cpu_cfg(env)->ext_svnapot && (pte & PTE_N)) {
-                napot_bits = ctzl(ppn) + 1;
-                if ((i != (levels - 1)) || (napot_bits != 4)) {
-                    return TRANSLATE_FAIL;
-                }
-            }
+            return TRANSLATE_FAIL;
+        }
+    }
 
-            napot_mask = (1 << napot_bits) - 1;
-            *physical = (((ppn & ~napot_mask) | (vpn & napot_mask) |
-                          (vpn & (((target_ulong)1 << ptshift) - 1))
-                         ) << PGSHIFT) | (addr & ~TARGET_PAGE_MASK);
+    /* For superpage mappings, make a fake leaf PTE for the TLB's benefit. */
+    target_ulong vpn = addr >> PGSHIFT;
 
-            /* set permissions on the TLB entry */
-            if ((pte & PTE_R) || ((pte & PTE_X) && mxr)) {
-                *prot |= PAGE_READ;
-            }
-            if (pte & PTE_X) {
-                *prot |= PAGE_EXEC;
-            }
-            /*
-             * add write permission on stores or if the page is already dirty,
-             * so that we TLB miss on later writes to update the dirty bit
-             */
-            if ((pte & PTE_W) &&
-                (access_type == MMU_DATA_STORE || (pte & PTE_D))) {
-                *prot |= PAGE_WRITE;
-            }
-            return TRANSLATE_SUCCESS;
+    if (riscv_cpu_cfg(env)->ext_svnapot && (pte & PTE_N)) {
+        napot_bits = ctzl(ppn) + 1;
+        if ((i != (levels - 1)) || (napot_bits != 4)) {
+            return TRANSLATE_FAIL;
         }
     }
-    return TRANSLATE_FAIL;
+
+    napot_mask = (1 << napot_bits) - 1;
+    *physical = (((ppn & ~napot_mask) | (vpn & napot_mask) |
+                  (vpn & (((target_ulong)1 << ptshift) - 1))
+                 ) << PGSHIFT) | (addr & ~TARGET_PAGE_MASK);
+
+    /* set permissions on the TLB entry */
+    if ((pte & PTE_R) || ((pte & PTE_X) && mxr)) {
+        *prot |= PAGE_READ;
+    }
+    if (pte & PTE_X) {
+        *prot |= PAGE_EXEC;
+    }
+    /*
+     * Add write permission on stores or if the page is already dirty,
+     * so that we TLB miss on later writes to update the dirty bit.
+     */
+    if ((pte & PTE_W) && (access_type == MMU_DATA_STORE || (pte & PTE_D))) {
+        *prot |= PAGE_WRITE;
+    }
+    return TRANSLATE_SUCCESS;
 }
 
 static void raise_mmu_exception(CPURISCVState *env, target_ulong address,