target/arm: Correctly implement Feat_DoubleLock
The architecture defines the OS DoubleLock as a register which
(similarly to the OS Lock) suppresses debug events for use in CPU
powerdown sequences. This functionality is required in Arm v7 and
v8.0; from v8.2 it becomes optional and in v9 it must not be
implemented.
Currently in QEMU we implement the OSDLR_EL1 register as a NOP. This
is wrong both for the "feature implemented" and the "feature not
implemented" cases: if the feature is implemented then the DLK bit
should read as written and cause suppression of debug exceptions, and
if it is not implemented then the bit must be RAZ/WI.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index c533ad0..1f4f3e0 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -500,6 +500,7 @@
uint64_t dbgwcr[16]; /* watchpoint control registers */
uint64_t mdscr_el1;
uint64_t oslsr_el1; /* OS Lock Status */
+ uint64_t osdlr_el1; /* OS DoubleLock status */
uint64_t mdcr_el2;
uint64_t mdcr_el3;
/* Stores the architectural value of the counter *the last time it was
@@ -2253,6 +2254,15 @@
FIELD(DBGDIDR, BRPS, 24, 4)
FIELD(DBGDIDR, WRPS, 28, 4)
+FIELD(DBGDEVID, PCSAMPLE, 0, 4)
+FIELD(DBGDEVID, WPADDRMASK, 4, 4)
+FIELD(DBGDEVID, BPADDRMASK, 8, 4)
+FIELD(DBGDEVID, VECTORCATCH, 12, 4)
+FIELD(DBGDEVID, VIRTEXTNS, 16, 4)
+FIELD(DBGDEVID, DOUBLELOCK, 20, 4)
+FIELD(DBGDEVID, AUXREGS, 24, 4)
+FIELD(DBGDEVID, CIDMASK, 28, 4)
+
FIELD(MVFR0, SIMDREG, 0, 4)
FIELD(MVFR0, FPSP, 4, 4)
FIELD(MVFR0, FPDP, 8, 4)
@@ -3731,6 +3741,11 @@
return FIELD_EX32(id->id_dfr0, ID_DFR0, COPDBG) >= 8;
}
+static inline bool isar_feature_aa32_doublelock(const ARMISARegisters *id)
+{
+ return FIELD_EX32(id->dbgdevid, DBGDEVID, DOUBLELOCK) > 0;
+}
+
/*
* 64-bit feature tests via id registers.
*/
@@ -4155,6 +4170,11 @@
return FIELD_EX64(id->id_aa64smfr0, ID_AA64SMFR0, FA64);
}
+static inline bool isar_feature_aa64_doublelock(const ARMISARegisters *id)
+{
+ return FIELD_SEX64(id->id_aa64dfr0, ID_AA64DFR0, DOUBLELOCK) >= 0;
+}
+
/*
* Feature tests for "does this exist in either 32-bit or 64-bit?"
*/
diff --git a/target/arm/debug_helper.c b/target/arm/debug_helper.c
index e96a4ff..d09fccb 100644
--- a/target/arm/debug_helper.c
+++ b/target/arm/debug_helper.c
@@ -142,7 +142,7 @@
*/
bool arm_generate_debug_exceptions(CPUARMState *env)
{
- if (env->cp15.oslsr_el1 & 1) {
+ if ((env->cp15.oslsr_el1 & 1) || (env->cp15.osdlr_el1 & 1)) {
return false;
}
if (is_a64(env)) {
@@ -614,6 +614,21 @@
env->cp15.oslsr_el1 = deposit32(env->cp15.oslsr_el1, 1, 1, oslock);
}
+static void osdlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
+ uint64_t value)
+{
+ ARMCPU *cpu = env_archcpu(env);
+ /*
+ * Only defined bit is bit 0 (DLK); if Feat_DoubleLock is not
+ * implemented this is RAZ/WI.
+ */
+ if(arm_feature(env, ARM_FEATURE_AARCH64)
+ ? cpu_isar_feature(aa64_doublelock, cpu)
+ : cpu_isar_feature(aa32_doublelock, cpu)) {
+ env->cp15.osdlr_el1 = value & 1;
+ }
+}
+
static const ARMCPRegInfo debug_cp_reginfo[] = {
/*
* DBGDRAR, DBGDSAR: always RAZ since we don't implement memory mapped
@@ -670,7 +685,8 @@
{ .name = "OSDLR_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 3, .opc2 = 4,
.access = PL1_RW, .accessfn = access_tdosa,
- .type = ARM_CP_NOP },
+ .writefn = osdlr_write,
+ .fieldoffset = offsetof(CPUARMState, cp15.osdlr_el1) },
/*
* Dummy DBGVCR: Linux wants to clear this on startup, but we don't
* implement vector catch debug events yet.
