diff mbox series

[v2] feat: add loongarch page table walker support for debugger memory access

Message ID 20241230071009.140412-1-haomiao23s@ict.ac.cn (mailing list archive)
State New
Headers show
Series [v2] feat: add loongarch page table walker support for debugger memory access | expand

Commit Message

Miao Hao Dec. 30, 2024, 7:10 a.m. UTC
Signed-off-by: Miao Hao <haomiao23s@ict.ac.cn>
---
  v1 -> v2:
    1. Addressed review comments.
    2. Fix the assignment of variable shift.

 target/loongarch/cpu_helper.c     | 106 ++++++++++++++++++++++++++++--
 target/loongarch/internals.h      |   4 +-
 target/loongarch/tcg/tlb_helper.c |   4 +-
 3 files changed, 106 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/target/loongarch/cpu_helper.c b/target/loongarch/cpu_helper.c
index 580362ac3e..9de7abfebf 100644
--- a/target/loongarch/cpu_helper.c
+++ b/target/loongarch/cpu_helper.c
@@ -141,9 +141,97 @@  bool loongarch_tlb_search(CPULoongArchState *env, target_ulong vaddr,
     return false;
 }
 
+static int loongarch_page_table_walker(CPULoongArchState *env, hwaddr *physical,
+                                 int *prot, target_ulong address)
+{
+    CPUState *cs = env_cpu(env);
+    target_ulong index, phys;
+    int shift;
+    uint64_t dir_base, dir_width;
+    uint64_t base;
+    int level;
+
+    /* 0:64bit, 1:128bit, 2:256bit, 3:512bit */
+    shift = FIELD_EX64(env->CSR_PWCL, CSR_PWCL, PTEWIDTH);
+    shift = shift + 3;
+
+    if ((address >> 63) & 0x1) {
+        base = env->CSR_PGDH;
+    } else {
+        base = env->CSR_PGDL;
+    }
+    base &= TARGET_PHYS_MASK;
+
+    for (level = 4; level > 0; level--) {
+        get_dir_base_width(env, &dir_base, &dir_width, level);
+
+        if (dir_width == 0) {
+            continue;
+        }
+
+        /* get next level page directory */
+        index = (address >> dir_base) & ((1 << dir_width) - 1);
+        phys = base | index << shift;
+        base = ldq_phys(cs->as, phys) & TARGET_PHYS_MASK;
+        if (!FIELD_EX64(base, TLBENTRY, HUGE)) {
+            /* mask off page dir permission bits */
+            base &= TARGET_PAGE_MASK;
+        } else {
+            /* base is a huge pte */
+            break;
+        }
+
+        if (base == 0) {
+            return TLBRET_NOMATCH;
+        }
+    }
+
+    /* pte */
+    if (FIELD_EX64(base, TLBENTRY, HUGE)) {
+        /* Huge Page. base is pte */
+        base = FIELD_DP64(base, TLBENTRY, LEVEL, 0);
+        base = FIELD_DP64(base, TLBENTRY, HUGE, 0);
+        if (FIELD_EX64(base, TLBENTRY, HGLOBAL)) {
+            base = FIELD_DP64(base, TLBENTRY, HGLOBAL, 0);
+            base = FIELD_DP64(base, TLBENTRY, G, 1);
+        }
+    } else {
+        /* Normal Page. base points to pte */
+        get_dir_base_width(env, &dir_base, &dir_width, 0);
+        index = (address >> dir_base) & ((1 << dir_width) - 1);
+        phys = base | index << shift;
+        base = ldq_phys(cs->as, phys);
+    }
+
+    /* TODO: check plv and other bits? */
+
+    /* base is pte, in normal pte format */
+    if (!FIELD_EX64(base, TLBENTRY, V)) {
+        return TLBRET_NOMATCH;
+    }
+
+    if (!FIELD_EX64(base, TLBENTRY, D)) {
+        *prot = PAGE_READ;
+    } else {
+        *prot = PAGE_READ | PAGE_WRITE;
+    }
+
+    /* get TARGET_PAGE_SIZE aligned physical address */
+    base += (address & TARGET_PHYS_MASK) & ((1 << dir_base) - 1);
+    /* mask RPLV, NX, NR bits */
+    base = FIELD_DP64(base, TLBENTRY_64, RPLV, 0);
+    base = FIELD_DP64(base, TLBENTRY_64, NX, 0);
+    base = FIELD_DP64(base, TLBENTRY_64, NR, 0);
+    /* mask other attribute bits */
+    *physical = base & TARGET_PAGE_MASK;
+
+    return 0;
+}
+
 static int loongarch_map_address(CPULoongArchState *env, hwaddr *physical,
                                  int *prot, target_ulong address,
-                                 MMUAccessType access_type, int mmu_idx)
+                                 MMUAccessType access_type, int mmu_idx,
+                                 int is_debug)
 {
     int index, match;
 
@@ -151,6 +239,13 @@  static int loongarch_map_address(CPULoongArchState *env, hwaddr *physical,
     if (match) {
         return loongarch_map_tlb_entry(env, physical, prot,
                                        address, access_type, index, mmu_idx);
+    } else if (is_debug) {
+        /*
+         * For debugger memory access, we want to do the map when there is a
+         * legal mapping, even if the mapping is not yet in TLB. return 0 if
+         * there is a valid map, else none zero.
+         */
+        return loongarch_page_table_walker(env, physical, prot, address);
     }
 
     return TLBRET_NOMATCH;
@@ -158,7 +253,8 @@  static int loongarch_map_address(CPULoongArchState *env, hwaddr *physical,
 #else
 static int loongarch_map_address(CPULoongArchState *env, hwaddr *physical,
                                  int *prot, target_ulong address,
-                                 MMUAccessType access_type, int mmu_idx)
+                                 MMUAccessType access_type, int mmu_idx,
+                                 int is_debug)
 {
     return TLBRET_NOMATCH;
 }
@@ -178,7 +274,7 @@  static hwaddr dmw_va2pa(CPULoongArchState *env, target_ulong va,
 
 int get_physical_address(CPULoongArchState *env, hwaddr *physical,
                          int *prot, target_ulong address,
-                         MMUAccessType access_type, int mmu_idx)
+                         MMUAccessType access_type, int mmu_idx, int is_debug)
 {
     int user_mode = mmu_idx == MMU_USER_IDX;
     int kernel_mode = mmu_idx == MMU_KERNEL_IDX;
@@ -222,7 +318,7 @@  int get_physical_address(CPULoongArchState *env, hwaddr *physical,
 
     /* Mapped address */
     return loongarch_map_address(env, physical, prot, address,
-                                 access_type, mmu_idx);
+                                 access_type, mmu_idx, is_debug);
 }
 
 hwaddr loongarch_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
@@ -232,7 +328,7 @@  hwaddr loongarch_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
     int prot;
 
     if (get_physical_address(env, &phys_addr, &prot, addr, MMU_DATA_LOAD,
-                             cpu_mmu_index(cs, false)) != 0) {
+                             cpu_mmu_index(cs, false), 1) != 0) {
         return -1;
     }
     return phys_addr;
diff --git a/target/loongarch/internals.h b/target/loongarch/internals.h
index 1a02427627..bc2ca30746 100644
--- a/target/loongarch/internals.h
+++ b/target/loongarch/internals.h
@@ -56,7 +56,9 @@  bool loongarch_tlb_search(CPULoongArchState *env, target_ulong vaddr,
                           int *index);
 int get_physical_address(CPULoongArchState *env, hwaddr *physical,
                          int *prot, target_ulong address,
-                         MMUAccessType access_type, int mmu_idx);
+                         MMUAccessType access_type, int mmu_idx, int is_debug);
+void get_dir_base_width(CPULoongArchState *env, uint64_t *dir_base,
+                               uint64_t *dir_width, target_ulong level);
 hwaddr loongarch_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 
 #ifdef CONFIG_TCG
diff --git a/target/loongarch/tcg/tlb_helper.c b/target/loongarch/tcg/tlb_helper.c
index 97f38fc391..564f336df9 100644
--- a/target/loongarch/tcg/tlb_helper.c
+++ b/target/loongarch/tcg/tlb_helper.c
@@ -18,7 +18,7 @@ 
 #include "exec/log.h"
 #include "cpu-csr.h"
 
-static void get_dir_base_width(CPULoongArchState *env, uint64_t *dir_base,
+void get_dir_base_width(CPULoongArchState *env, uint64_t *dir_base,
                                uint64_t *dir_width, target_ulong level)
 {
     switch (level) {
@@ -485,7 +485,7 @@  bool loongarch_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 
     /* Data access */
     ret = get_physical_address(env, &physical, &prot, address,
-                               access_type, mmu_idx);
+                               access_type, mmu_idx, 0);
 
     if (ret == TLBRET_MATCH) {
         tlb_set_page(cs, address & TARGET_PAGE_MASK,