target/arm: Convert arm_mmu_idx_to_el from switch to table

In an effort to keep all ARMMMUIdx data in one place, begin construction
of an info table describing all of the properties of the mmu_idx.  Begin
with the access EL.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20251008215613.300150-18-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/helper.c

@@ -9653,33 +9653,6 @@ int fp_exception_el(CPUARMState *env, int cur_el)
     return 0;
 }
 
-/* Return the exception level we're running at if this is our mmu_idx */
-int arm_mmu_idx_to_el(ARMMMUIdx mmu_idx)
-{
-    if (mmu_idx & ARM_MMU_IDX_M) {
-        return mmu_idx & ARM_MMU_IDX_M_PRIV;
-    }
-
-    switch (mmu_idx) {
-    case ARMMMUIdx_E10_0:
-    case ARMMMUIdx_E20_0:
-    case ARMMMUIdx_E30_0:
-        return 0;
-    case ARMMMUIdx_E10_1:
-    case ARMMMUIdx_E10_1_PAN:
-        return 1;
-    case ARMMMUIdx_E2:
-    case ARMMMUIdx_E20_2:
-    case ARMMMUIdx_E20_2_PAN:
-        return 2;
-    case ARMMMUIdx_E3:
-    case ARMMMUIdx_E30_3_PAN:
-        return 3;
-    default:
-        g_assert_not_reached();
-    }
-}
-
 #ifndef CONFIG_TCG
 ARMMMUIdx arm_v7m_mmu_idx_for_secstate(CPUARMState *env, bool secstate)
 {

target/arm/internals.h

@@ -34,6 +34,7 @@
 #include "system/memory.h"
 #include "syndrome.h"
 #include "cpu-features.h"
+#include "mmuidx-internal.h"
 
 /* register banks for CPU modes */
 #define BANK_USRSYS 0
@@ -984,8 +985,6 @@ static inline ARMMMUIdx core_to_aa64_mmu_idx(int mmu_idx)
     return mmu_idx | ARM_MMU_IDX_A;
 }
 
-int arm_mmu_idx_to_el(ARMMMUIdx mmu_idx);
-
 /* Return the MMU index for a v7M CPU in the specified security state */
 ARMMMUIdx arm_v7m_mmu_idx_for_secstate(CPUARMState *env, bool secstate);
 

target/arm/meson.build

@@ -6,7 +6,12 @@ arm_ss.add(files(
 
 arm_ss.add(when: 'TARGET_AARCH64', if_true: files(
   'cpu64.c',
-  'gdbstub64.c'))
+  'gdbstub64.c'
+))
+
+arm_common_ss.add(files(
+  'mmuidx.c',
+))
 
 arm_system_ss = ss.source_set()
 arm_common_system_ss = ss.source_set()

target/arm/mmuidx-internal.h

@@ -0,0 +1,29 @@
+/*
+ * QEMU Arm software mmu index internal definitions
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef TARGET_ARM_MMUIDX_INTERNAL_H
+#define TARGET_ARM_MMUIDX_INTERNAL_H
+
+#include "mmuidx.h"
+#include "tcg/debug-assert.h"
+#include "hw/registerfields.h"
+
+
+FIELD(MMUIDXINFO, EL, 0, 2)
+FIELD(MMUIDXINFO, ELVALID, 2, 1)
+
+extern const uint32_t arm_mmuidx_table[ARM_MMU_IDX_M + 8];
+
+#define arm_mmuidx_is_valid(x)  ((unsigned)(x) < ARRAY_SIZE(arm_mmuidx_table))
+
+/* Return the exception level associated with this mmu index. */
+static inline int arm_mmu_idx_to_el(ARMMMUIdx idx)
+{
+    tcg_debug_assert(arm_mmuidx_is_valid(idx));
+    tcg_debug_assert(FIELD_EX32(arm_mmuidx_table[idx], MMUIDXINFO, ELVALID));
+    return FIELD_EX32(arm_mmuidx_table[idx], MMUIDXINFO, EL);
+}
+
+#endif /* TARGET_ARM_MMUIDX_INTERNAL_H */

target/arm/mmuidx.c

@@ -0,0 +1,41 @@
+/*
+ * QEMU Arm software mmu index definitions
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "mmuidx-internal.h"
+
+
+#define EL(X)  ((X << R_MMUIDXINFO_EL_SHIFT) | R_MMUIDXINFO_ELVALID_MASK)
+
+const uint32_t arm_mmuidx_table[ARM_MMU_IDX_M + 8] = {
+    /*
+     * A-profile.
+     */
+    [ARMMMUIdx_E10_0]           = EL(0),
+    [ARMMMUIdx_E10_1]           = EL(1),
+    [ARMMMUIdx_E10_1_PAN]       = EL(1),
+
+    [ARMMMUIdx_E20_0]           = EL(0),
+    [ARMMMUIdx_E20_2]           = EL(2),
+    [ARMMMUIdx_E20_2_PAN]       = EL(2),
+
+    [ARMMMUIdx_E2]              = EL(2),
+
+    [ARMMMUIdx_E3]              = EL(3),
+    [ARMMMUIdx_E30_0]           = EL(0),
+    [ARMMMUIdx_E30_3_PAN]       = EL(3),
+
+    /*
+     * M-profile.
+     */
+    [ARMMMUIdx_MUser]           = EL(0),
+    [ARMMMUIdx_MPriv]           = EL(1),
+    [ARMMMUIdx_MUserNegPri]     = EL(0),
+    [ARMMMUIdx_MPrivNegPri]     = EL(1),
+    [ARMMMUIdx_MSUser]          = EL(0),
+    [ARMMMUIdx_MSPriv]          = EL(1),
+    [ARMMMUIdx_MSUserNegPri]    = EL(0),
+    [ARMMMUIdx_MSPrivNegPri]    = EL(1),
+};