[Qemu-devel] [PATCH v4 21/22] target/arm: Add allocation tag storage for system mode

[Richard Henderson <richard.henderson@linaro.org>]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/mte_helper.c | 56 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 6d0f82eb99..6657f57ca6 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -28,8 +28,64 @@
 static uint8_t *allocation_tag_mem(CPUARMState *env, uint64_t ptr,
                                    bool write, uintptr_t ra)
 {
+#ifdef CONFIG_USER_ONLY
     /* Tag storage not implemented.  */
     return NULL;
+#else
+    ARMCPU *cpu = arm_env_get_cpu(env);
+    CPUState *cs = CPU(cpu);
+    uintptr_t index;
+    int mmu_idx;
+    CPUTLBEntry *te;
+    CPUIOTLBEntry *iotlbentry;
+    MemoryRegionSection *section;
+    hwaddr physaddr, tag_physaddr;
+
+    /*
+     * Find the TLB entry for this access.
+     * As a side effect, this also raises an exception for invalid access.
+     */
+    mmu_idx = cpu_mmu_index(env, false);
+    index = tlb_index(env, mmu_idx, ptr);
+    te = tlb_entry(env, mmu_idx, ptr);
+    if (!tlb_hit(write ? tlb_addr_write(te) : te->addr_read, ptr)) {
+        /* ??? Expose VICTIM_TLB_HIT from accel/tcg/cputlb.c.  */
+        tlb_fill(cs, ptr, 16, write ? MMU_DATA_STORE : MMU_DATA_LOAD,
+                 mmu_idx, ra);
+        index = tlb_index(env, mmu_idx, ptr);
+        te = tlb_entry(env, mmu_idx, ptr);
+    }
+
+    /* If the virtual page MemAttr != Tagged, nothing to do.  */
+    iotlbentry = &env->iotlb[mmu_idx][index];
+    if (!iotlbentry->attrs.target_tlb_bit1) {
+        return NULL;
+    }
+
+    /* If the board did not allocate tag memory, nothing to do.  */
+    if (!cpu_get_address_space(cs, ARMASIdx_TAG)) {
+        return NULL;
+    }
+
+    /* Find the physical address for the virtual access.  */
+    section = iotlb_to_section(cs, iotlbentry->addr, iotlbentry->attrs);
+    physaddr = ((iotlbentry->addr & TARGET_PAGE_MASK) + ptr
+                + section->offset_within_address_space
+                - section->offset_within_region);
+    tag_physaddr = physaddr >> (LOG2_TAG_GRANULE + 1);
+
+    /* Find the memory backing the tag address in tag address space.  */
+    mmu_idx = arm_to_core_mmu_idx(ARMMMUIdx_TagNS);
+    te = tlb_entry(env, mmu_idx, tag_physaddr);
+    if (!tlb_hit(write ? tlb_addr_write(te) : te->addr_read, tag_physaddr)) {
+        /* ??? Expose VICTIM_TLB_HIT from accel/tcg/cputlb.c.  */
+        tlb_fill(cs, tag_physaddr, 1, write ? MMU_DATA_STORE : MMU_DATA_LOAD,
+                 mmu_idx, ra);
+        te = tlb_entry(env, mmu_idx, tag_physaddr);
+    }
+
+    return (void *)(tag_physaddr + te->addend);
+#endif
 }
 
 static int get_allocation_tag(CPUARMState *env, uint64_t ptr, uintptr_t ra)
-- 
2.17.2