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-rw-r--r--target-arm/cpu.c1
-rw-r--r--target-arm/helper.c7
-rw-r--r--target-arm/internals.h9
-rw-r--r--target-arm/op_helper.c188
4 files changed, 204 insertions, 1 deletions
diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 6c40ecdeed..7ea12bda1c 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -1065,6 +1065,7 @@ static void arm_cpu_class_init(ObjectClass *oc, void *data)
#endif
cc->gdb_num_core_regs = 26;
cc->gdb_core_xml_file = "arm-core.xml";
+ cc->debug_excp_handler = arm_debug_excp_handler;
}
static void cpu_register(const ARMCPUInfo *info)
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 5fd5497a35..b0d2424df3 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2399,14 +2399,18 @@ static void define_debug_regs(ARMCPU *cpu)
* These are just dummy implementations for now.
*/
int i;
- int wrps, brps;
+ int wrps, brps, ctx_cmps;
ARMCPRegInfo dbgdidr = {
.name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 0,
.access = PL0_R, .type = ARM_CP_CONST, .resetvalue = cpu->dbgdidr,
};
+ /* Note that all these register fields hold "number of Xs minus 1". */
brps = extract32(cpu->dbgdidr, 24, 4);
wrps = extract32(cpu->dbgdidr, 28, 4);
+ ctx_cmps = extract32(cpu->dbgdidr, 20, 4);
+
+ assert(ctx_cmps <= brps);
/* The DBGDIDR and ID_AA64DFR0_EL1 define various properties
* of the debug registers such as number of breakpoints;
@@ -2415,6 +2419,7 @@ static void define_debug_regs(ARMCPU *cpu)
if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
assert(extract32(cpu->id_aa64dfr0, 12, 4) == brps);
assert(extract32(cpu->id_aa64dfr0, 20, 4) == wrps);
+ assert(extract32(cpu->id_aa64dfr0, 28, 4) == ctx_cmps);
}
define_one_arm_cp_reg(cpu, &dbgdidr);
diff --git a/target-arm/internals.h b/target-arm/internals.h
index 1d788b0e94..64751a0798 100644
--- a/target-arm/internals.h
+++ b/target-arm/internals.h
@@ -307,6 +307,12 @@ static inline uint32_t syn_swstep(int same_el, int isv, int ex)
| (isv << 24) | (ex << 6) | 0x22;
}
+static inline uint32_t syn_watchpoint(int same_el, int cm, int wnr)
+{
+ return (EC_WATCHPOINT << ARM_EL_EC_SHIFT) | (same_el << ARM_EL_EC_SHIFT)
+ | (cm << 8) | (wnr << 6) | 0x22;
+}
+
/* Update a QEMU watchpoint based on the information the guest has set in the
* DBGWCR<n>_EL1 and DBGWVR<n>_EL1 registers.
*/
@@ -317,4 +323,7 @@ void hw_watchpoint_update(ARMCPU *cpu, int n);
*/
void hw_watchpoint_update_all(ARMCPU *cpu);
+/* Callback function for when a watchpoint or breakpoint triggers. */
+void arm_debug_excp_handler(CPUState *cs);
+
#endif
diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index fe40358c96..b956216c4b 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -456,6 +456,194 @@ illegal_return:
}
}
+/* Return true if the linked breakpoint entry lbn passes its checks */
+static bool linked_bp_matches(ARMCPU *cpu, int lbn)
+{
+ CPUARMState *env = &cpu->env;
+ uint64_t bcr = env->cp15.dbgbcr[lbn];
+ int brps = extract32(cpu->dbgdidr, 24, 4);
+ int ctx_cmps = extract32(cpu->dbgdidr, 20, 4);
+ int bt;
+ uint32_t contextidr;
+
+ /* Links to unimplemented or non-context aware breakpoints are
+ * CONSTRAINED UNPREDICTABLE: either behave as if disabled, or
+ * as if linked to an UNKNOWN context-aware breakpoint (in which
+ * case DBGWCR<n>_EL1.LBN must indicate that breakpoint).
+ * We choose the former.
+ */
+ if (lbn > brps || lbn < (brps - ctx_cmps)) {
+ return false;
+ }
+
+ bcr = env->cp15.dbgbcr[lbn];
+
+ if (extract64(bcr, 0, 1) == 0) {
+ /* Linked breakpoint disabled : generate no events */
+ return false;
+ }
+
+ bt = extract64(bcr, 20, 4);
+
+ /* We match the whole register even if this is AArch32 using the
+ * short descriptor format (in which case it holds both PROCID and ASID),
+ * since we don't implement the optional v7 context ID masking.
+ */
+ contextidr = extract64(env->cp15.contextidr_el1, 0, 32);
+
+ switch (bt) {
+ case 3: /* linked context ID match */
+ if (arm_current_pl(env) > 1) {
+ /* Context matches never fire in EL2 or (AArch64) EL3 */
+ return false;
+ }
+ return (contextidr == extract64(env->cp15.dbgbvr[lbn], 0, 32));
+ case 5: /* linked address mismatch (reserved in AArch64) */
+ case 9: /* linked VMID match (reserved if no EL2) */
+ case 11: /* linked context ID and VMID match (reserved if no EL2) */
+ default:
+ /* Links to Unlinked context breakpoints must generate no
+ * events; we choose to do the same for reserved values too.
+ */
+ return false;
+ }
+
+ return false;
+}
+
+static bool wp_matches(ARMCPU *cpu, int n)
+{
+ CPUARMState *env = &cpu->env;
+ uint64_t wcr = env->cp15.dbgwcr[n];
+ int pac, hmc, ssc, wt, lbn;
+ /* TODO: check against CPU security state when we implement TrustZone */
+ bool is_secure = false;
+
+ if (!env->cpu_watchpoint[n]
+ || !(env->cpu_watchpoint[n]->flags & BP_WATCHPOINT_HIT)) {
+ return false;
+ }
+
+ /* The WATCHPOINT_HIT flag guarantees us that the watchpoint is
+ * enabled and that the address and access type match; check the
+ * remaining fields, including linked breakpoints.
+ * Note that some combinations of {PAC, HMC SSC} are reserved and
+ * must act either like some valid combination or as if the watchpoint
+ * were disabled. We choose the former, and use this together with
+ * the fact that EL3 must always be Secure and EL2 must always be
+ * Non-Secure to simplify the code slightly compared to the full
+ * table in the ARM ARM.
+ */
+ pac = extract64(wcr, 1, 2);
+ hmc = extract64(wcr, 13, 1);
+ ssc = extract64(wcr, 14, 2);
+
+ switch (ssc) {
+ case 0:
+ break;
+ case 1:
+ case 3:
+ if (is_secure) {
+ return false;
+ }
+ break;
+ case 2:
+ if (!is_secure) {
+ return false;
+ }
+ break;
+ }
+
+ /* TODO: this is not strictly correct because the LDRT/STRT/LDT/STT
+ * "unprivileged access" instructions should match watchpoints as if
+ * they were accesses done at EL0, even if the CPU is at EL1 or higher.
+ * Implementing this would require reworking the core watchpoint code
+ * to plumb the mmu_idx through to this point. Luckily Linux does not
+ * rely on this behaviour currently.
+ */
+ switch (arm_current_pl(env)) {
+ case 3:
+ case 2:
+ if (!hmc) {
+ return false;
+ }
+ break;
+ case 1:
+ if (extract32(pac, 0, 1) == 0) {
+ return false;
+ }
+ break;
+ case 0:
+ if (extract32(pac, 1, 1) == 0) {
+ return false;
+ }
+ break;
+ default:
+ g_assert_not_reached();
+ }
+
+ wt = extract64(wcr, 20, 1);
+ lbn = extract64(wcr, 16, 4);
+
+ if (wt && !linked_bp_matches(cpu, lbn)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool check_watchpoints(ARMCPU *cpu)
+{
+ CPUARMState *env = &cpu->env;
+ int n;
+
+ /* If watchpoints are disabled globally or we can't take debug
+ * exceptions here then watchpoint firings are ignored.
+ */
+ if (extract32(env->cp15.mdscr_el1, 15, 1) == 0
+ || !arm_generate_debug_exceptions(env)) {
+ return false;
+ }
+
+ for (n = 0; n < ARRAY_SIZE(env->cpu_watchpoint); n++) {
+ if (wp_matches(cpu, n)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+void arm_debug_excp_handler(CPUState *cs)
+{
+ /* Called by core code when a watchpoint or breakpoint fires;
+ * need to check which one and raise the appropriate exception.
+ */
+ ARMCPU *cpu = ARM_CPU(cs);
+ CPUARMState *env = &cpu->env;
+ CPUWatchpoint *wp_hit = cs->watchpoint_hit;
+
+ if (wp_hit) {
+ if (wp_hit->flags & BP_CPU) {
+ cs->watchpoint_hit = NULL;
+ if (check_watchpoints(cpu)) {
+ bool wnr = (wp_hit->flags & BP_WATCHPOINT_HIT_WRITE) != 0;
+ bool same_el = arm_debug_target_el(env) == arm_current_pl(env);
+
+ env->exception.syndrome = syn_watchpoint(same_el, 0, wnr);
+ if (extended_addresses_enabled(env)) {
+ env->exception.fsr = (1 << 9) | 0x22;
+ } else {
+ env->exception.fsr = 0x2;
+ }
+ env->exception.vaddress = wp_hit->hitaddr;
+ raise_exception(env, EXCP_DATA_ABORT);
+ } else {
+ cpu_resume_from_signal(cs, NULL);
+ }
+ }
+ }
+}
+
/* ??? Flag setting arithmetic is awkward because we need to do comparisons.
The only way to do that in TCG is a conditional branch, which clobbers
all our temporaries. For now implement these as helper functions. */
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-17 23:08:32 +0000