[Qemu-devel] [PULL 02/19] target-arm: Collect up the debug cp register definitions

[Peter Maydell <peter.maydell@linaro.org>]

At the moment we have a mixed set of mostly dummy register
definitions for various debug related registers which have
been added piecemeal in order to get Linux kernels to boot.
In preparation for actually implementing debug support,
bring them all together into one place.

This commit doesn't change behaviour: we still expose
exactly the same registers and behaviour to the guest
in all configurations.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
---
 target-arm/helper.c | 85 +++++++++++++++++++++++++++++++++--------------------
 1 file changed, 53 insertions(+), 32 deletions(-)

diff --git a/target-arm/helper.c b/target-arm/helper.c
index f630d96..a9be7ba 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -389,12 +389,6 @@ static void tlbimvaa_write(CPUARMState *env, const ARMCPRegInfo *ri,
 }
 
 static const ARMCPRegInfo cp_reginfo[] = {
-    /* DBGDIDR: just RAZ. In particular this means the "debug architecture
-     * version" bits will read as a reserved value, which should cause
-     * Linux to not try to use the debug hardware.
-     */
-    { .name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 0,
-      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
     { .name = "FCSEIDR", .cp = 15, .crn = 13, .crm = 0, .opc1 = 0, .opc2 = 0,
       .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.c13_fcse),
       .resetvalue = 0, .writefn = fcse_write, .raw_writefn = raw_write, },
@@ -471,6 +465,13 @@ static const ARMCPRegInfo not_v7_cp_reginfo[] = {
     { .name = "DUMMY", .cp = 15, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = CP_ANY,
       .access = PL1_R, .type = ARM_CP_CONST | ARM_CP_NO_MIGRATE,
       .resetvalue = 0 },
+    /* We don't implement pre-v7 debug but most CPUs had at least a DBGDIDR;
+     * implementing it as RAZ means the "debug architecture version" bits
+     * will read as a reserved value, which should cause Linux to not try
+     * to use the debug hardware.
+     */
+    { .name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 0,
+      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
     REGINFO_SENTINEL
 };
 
@@ -712,13 +713,6 @@ static uint64_t isr_read(CPUARMState *env, const ARMCPRegInfo *ri)
 }
 
 static const ARMCPRegInfo v7_cp_reginfo[] = {
-    /* DBGDRAR, DBGDSAR: always RAZ since we don't implement memory mapped
-     * debug components
-     */
-    { .name = "DBGDRAR", .cp = 14, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
-      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
-    { .name = "DBGDSAR", .cp = 14, .crn = 2, .crm = 0, .opc1 = 0, .opc2 = 0,
-      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
     /* the old v6 WFI, UNPREDICTABLE in v7 but we choose to NOP */
     { .name = "NOP", .cp = 15, .crn = 7, .crm = 0, .opc1 = 0, .opc2 = 4,
       .access = PL1_W, .type = ARM_CP_NOP },
@@ -1734,11 +1728,6 @@ static const ARMCPRegInfo lpae_cp_reginfo[] = {
     { .name = "AMAIR1", .cp = 15, .crn = 10, .crm = 3, .opc1 = 0, .opc2 = 1,
       .access = PL1_RW, .type = ARM_CP_CONST | ARM_CP_OVERRIDE,
       .resetvalue = 0 },
-    /* 64 bit access versions of the (dummy) debug registers */
-    { .name = "DBGDRAR", .cp = 14, .crm = 1, .opc1 = 0,
-      .access = PL0_R, .type = ARM_CP_CONST|ARM_CP_64BIT, .resetvalue = 0 },
-    { .name = "DBGDSAR", .cp = 14, .crm = 2, .opc1 = 0,
-      .access = PL0_R, .type = ARM_CP_CONST|ARM_CP_64BIT, .resetvalue = 0 },
     { .name = "PAR", .cp = 15, .crm = 7, .opc1 = 0,
       .access = PL1_RW, .type = ARM_CP_64BIT,
       .fieldoffset = offsetof(CPUARMState, cp15.par_el1), .resetvalue = 0 },
@@ -2083,16 +2072,6 @@ static const ARMCPRegInfo v8_cp_reginfo[] = {
       .opc1 = 0, .crn = 3, .crm = 0, .opc2 = 0,
       .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.c3),
       .resetvalue = 0, .writefn = dacr_write, .raw_writefn = raw_write, },
-    /* Dummy implementation of monitor debug system control register:
-     * we don't support debug.
-     */
-    { .name = "MDSCR_EL1", .state = ARM_CP_STATE_AA64,
-      .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
-      .access = PL1_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
-    /* We define a dummy WI OSLAR_EL1, because Linux writes to it. */
-    { .name = "OSLAR_EL1", .state = ARM_CP_STATE_AA64,
-      .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
-      .access = PL1_W, .type = ARM_CP_NOP },
     { .name = "ELR_EL1", .state = ARM_CP_STATE_AA64,
       .type = ARM_CP_NO_MIGRATE,
       .opc0 = 3, .opc1 = 0, .crn = 4, .crm = 0, .opc2 = 1,
@@ -2206,13 +2185,55 @@ static CPAccessResult ctr_el0_access(CPUARMState *env, const ARMCPRegInfo *ri)
     return CP_ACCESS_OK;
 }
 
-static void define_aarch64_debug_regs(ARMCPU *cpu)
+static const ARMCPRegInfo debug_cp_reginfo[] = {
+    /* DBGDIDR: just RAZ. In particular this means the "debug architecture
+     * version" bits will read as a reserved value, which should cause
+     * Linux to not try to use the debug hardware.
+     */
+    { .name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 0,
+      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+    /* DBGDRAR, DBGDSAR: always RAZ since we don't implement memory mapped
+     * debug components
+     */
+    { .name = "DBGDRAR", .cp = 14, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
+      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+    { .name = "DBGDSAR", .cp = 14, .crn = 2, .crm = 0, .opc1 = 0, .opc2 = 0,
+      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+    /* Dummy implementation of monitor debug system control register:
+     * we don't support debug.
+     */
+    { .name = "MDSCR_EL1", .state = ARM_CP_STATE_AA64,
+      .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
+      .access = PL1_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
+    /* We define a dummy WI OSLAR_EL1, because Linux writes to it. */
+    { .name = "OSLAR_EL1", .state = ARM_CP_STATE_AA64,
+      .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
+      .access = PL1_W, .type = ARM_CP_NOP },
+    REGINFO_SENTINEL
+};
+
+static const ARMCPRegInfo debug_lpae_cp_reginfo[] = {
+    /* 64 bit access versions of the (dummy) debug registers */
+    { .name = "DBGDRAR", .cp = 14, .crm = 1, .opc1 = 0,
+      .access = PL0_R, .type = ARM_CP_CONST|ARM_CP_64BIT, .resetvalue = 0 },
+    { .name = "DBGDSAR", .cp = 14, .crm = 2, .opc1 = 0,
+      .access = PL0_R, .type = ARM_CP_CONST|ARM_CP_64BIT, .resetvalue = 0 },
+    REGINFO_SENTINEL
+};
+
+static void define_debug_regs(ARMCPU *cpu)
 {
-    /* Define breakpoint and watchpoint registers. These do nothing
-     * but read as written, for now.
+    /* Define v7 and v8 architectural debug registers.
+     * These are just dummy implementations for now.
      */
     int i;
 
+    define_arm_cp_regs(cpu, debug_cp_reginfo);
+
+    if (arm_feature(&cpu->env, ARM_FEATURE_LPAE)) {
+        define_arm_cp_regs(cpu, debug_lpae_cp_reginfo);
+    }
+
     for (i = 0; i < 16; i++) {
         ARMCPRegInfo dbgregs[] = {
             { .name = "DBGBVR", .state = ARM_CP_STATE_AA64,
@@ -2353,6 +2374,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         };
         define_one_arm_cp_reg(cpu, &clidr);
         define_arm_cp_regs(cpu, v7_cp_reginfo);
+        define_debug_regs(cpu);
     } else {
         define_arm_cp_regs(cpu, not_v7_cp_reginfo);
     }
@@ -2426,7 +2448,6 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         define_one_arm_cp_reg(cpu, &rvbar);
         define_arm_cp_regs(cpu, v8_idregs);
         define_arm_cp_regs(cpu, v8_cp_reginfo);
-        define_aarch64_debug_regs(cpu);
     }
     if (arm_feature(env, ARM_FEATURE_EL2)) {
         define_arm_cp_regs(cpu, v8_el2_cp_reginfo);
-- 
1.9.1