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target/riscv: Mismatch napot when mcontrol.maskmax is not expected #1127

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Oct 4, 2024
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target/riscv: Mismatch napot when mcontrol.maskmax is not expected #1127

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111 changes: 68 additions & 43 deletions src/target/riscv/riscv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -621,8 +621,17 @@ static int find_first_trigger_by_id(struct target *target, int unique_id)
return -1;
}

static int set_trigger(struct target *target, unsigned int idx, riscv_reg_t tdata1, riscv_reg_t tdata2,
riscv_reg_t tdata1_ignore_mask)
static unsigned int count_trailing_ones(riscv_reg_t reg)
{
assert(sizeof(riscv_reg_t) * 8 == 64);
for (unsigned int i = 0; i < 64; i++) {
Comment on lines +626 to +627
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Suggested change
assert(sizeof(riscv_reg_t) * 8 == 64);
for (unsigned int i = 0; i < 64; i++) {
const unsigned int riscv_reg_bits = sizeof(riscv_reg_t) * CHAR_BIT;
for (unsigned int i = 0; i < riscv_reg_bits; i++) {

if ((1 & (reg >> i)) == 0)
return i;
}
return 64;
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Suggested change
return 64;
return riscv_reg_bits;

}

static int set_trigger(struct target *target, unsigned int idx, riscv_reg_t tdata1, riscv_reg_t tdata2)
{
RISCV_INFO(r);
assert(r->reserved_triggers);
Expand Down Expand Up @@ -655,20 +664,51 @@ static int set_trigger(struct target *target, unsigned int idx, riscv_reg_t tdat
return ERROR_FAIL;
if (riscv_reg_get(target, &tdata2_rb, GDB_REGNO_TDATA2) != ERROR_OK)
return ERROR_FAIL;
bool tdata1_config_denied = (tdata1 & ~tdata1_ignore_mask) != (tdata1_rb & ~tdata1_ignore_mask);
bool tdata2_config_denied = tdata2 != tdata2_rb;
if (tdata1_config_denied || tdata2_config_denied) {

const uint32_t type = get_field(tdata1, CSR_TDATA1_TYPE(riscv_xlen(target)));
const bool is_mcontrol = type == CSR_TDATA1_TYPE_MCONTROL;

/* Determine if tdata1 supports what we need.
* For mcontrol triggers, we don't care about
* the value in the read-only "maskmax" field.
*/
const riscv_reg_t tdata1_ignore_mask = is_mcontrol ? CSR_MCONTROL_MASKMAX(riscv_xlen(target)) : 0;
const bool tdata1_config_denied = (tdata1 & ~tdata1_ignore_mask) != (tdata1_rb & ~tdata1_ignore_mask);

/* Determine if tdata1.maxmask is sufficient
* (only relevant for mcontrol triggers and NAPOT match type)
*/
bool unsupported_napot_range = false;
riscv_reg_t maskmax_value = 0;
if (!tdata1_config_denied) {
const bool is_napot_match = get_field(tdata1_rb, CSR_MCONTROL_MATCH) == CSR_MCONTROL_MATCH_NAPOT;
if (is_mcontrol && is_napot_match) {
maskmax_value = get_field(tdata1_rb, CSR_MCONTROL_MASKMAX(riscv_xlen(target)));
const unsigned int napot_size = count_trailing_ones(tdata2) + 1;
if (maskmax_value < napot_size)
unsupported_napot_range = true;
}
}

const bool tdata2_config_denied = tdata2 != tdata2_rb;
if (tdata1_config_denied || tdata2_config_denied || unsupported_napot_range) {
LOG_TARGET_DEBUG(target, "Trigger %u doesn't support what we need.", idx);

if (tdata1_config_denied)
LOG_TARGET_DEBUG(target,
"After writing 0x%" PRIx64 " to tdata1 it contains 0x%" PRIx64 "; tdata1_ignore_mask=0x%" PRIx64,
tdata1, tdata1_rb, tdata1_ignore_mask);
"After writing 0x%" PRIx64 " to tdata1 it contains 0x%" PRIx64,
tdata1, tdata1_rb);

if (tdata2_config_denied)
LOG_TARGET_DEBUG(target,
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"wrote 0x%" PRIx64 " to tdata2 but read back 0x%" PRIx64,
"After writing 0x%" PRIx64 " to tdata2 it contains 0x%" PRIx64,
tdata2, tdata2_rb);

if (unsupported_napot_range)
LOG_TARGET_DEBUG(target,
"The requested NAPOT match range (tdata2=0x%" PRIx64 ") exceeds maskmax_value=0x%" PRIx64,
tdata2, maskmax_value);

if (riscv_reg_set(target, GDB_REGNO_TDATA1, 0) != ERROR_OK)
return ERROR_FAIL;
return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
Expand Down Expand Up @@ -717,7 +757,7 @@ static int maybe_add_trigger_t1(struct target *target, struct trigger *trigger)
tdata1 = set_field(tdata1, bpcontrol_bpaction, 0); /* cause bp exception */
tdata1 = set_field(tdata1, bpcontrol_bpmatch, 0); /* exact match */
tdata2 = trigger->address;
ret = set_trigger(target, idx, tdata1, tdata2, 0);
ret = set_trigger(target, idx, tdata1, tdata2);
if (ret != ERROR_OK)
return ret;
r->trigger_unique_id[idx] = trigger->unique_id;
Expand All @@ -727,13 +767,11 @@ static int maybe_add_trigger_t1(struct target *target, struct trigger *trigger)
struct trigger_request_info {
riscv_reg_t tdata1;
riscv_reg_t tdata2;
riscv_reg_t tdata1_ignore_mask;
};

static void log_trigger_request_info(struct trigger_request_info trig_info)
{
LOG_DEBUG("tdata1=%" PRIx64 ", tdata2=%" PRIx64 ", tdata1_ignore_mask=%" PRIx64,
trig_info.tdata1, trig_info.tdata2, trig_info.tdata1_ignore_mask);
LOG_DEBUG("tdata1=%" PRIx64 ", tdata2=%" PRIx64, trig_info.tdata1, trig_info.tdata2);
};

static struct tdata1_cache *tdata1_cache_alloc(struct list_head *tdata1_cache_head, riscv_reg_t tdata1)
Expand Down Expand Up @@ -816,12 +854,12 @@ static bool wp_triggers_cache_search(struct target *target, unsigned int idx,
}

static int try_use_trigger_and_cache_result(struct target *target, unsigned int idx, riscv_reg_t tdata1,
riscv_reg_t tdata2, riscv_reg_t tdata1_ignore_mask)
riscv_reg_t tdata2)
{
if (wp_triggers_cache_search(target, idx, tdata1, tdata2))
return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;

int ret = set_trigger(target, idx, tdata1, tdata2, tdata1_ignore_mask);
int ret = set_trigger(target, idx, tdata1, tdata2);

/* Add these values to the cache to remember that they are not supported. */
if (ret == ERROR_TARGET_RESOURCE_NOT_AVAILABLE)
Expand All @@ -844,8 +882,7 @@ static int try_setup_single_match_trigger(struct target *target,
for (unsigned int idx = 0;
find_next_free_trigger(target, trigger_type, false, &idx) == ERROR_OK;
++idx) {
ret = try_use_trigger_and_cache_result(target, idx, trig_info.tdata1, trig_info.tdata2,
trig_info.tdata1_ignore_mask);
ret = try_use_trigger_and_cache_result(target, idx, trig_info.tdata1, trig_info.tdata2);

if (ret == ERROR_OK) {
r->trigger_unique_id[idx] = trigger->unique_id;
Expand Down Expand Up @@ -873,24 +910,22 @@ static int try_setup_chained_match_triggers(struct target *target,
for (unsigned int idx = 0;
find_next_free_trigger(target, trigger_type, true, &idx) == ERROR_OK;
++idx) {
ret = try_use_trigger_and_cache_result(target, idx, t1.tdata1, t1.tdata2,
t1.tdata1_ignore_mask);
ret = try_use_trigger_and_cache_result(target, idx, t1.tdata1, t1.tdata2);

if (ret == ERROR_TARGET_RESOURCE_NOT_AVAILABLE)
continue;
else if (ret != ERROR_OK)
return ret;

ret = try_use_trigger_and_cache_result(target, idx + 1, t2.tdata1, t2.tdata2,
t2.tdata1_ignore_mask);
ret = try_use_trigger_and_cache_result(target, idx + 1, t2.tdata1, t2.tdata2);

if (ret == ERROR_OK) {
r->trigger_unique_id[idx] = trigger->unique_id;
r->trigger_unique_id[idx + 1] = trigger->unique_id;
return ERROR_OK;
}
/* Undo the setting of the previous trigger */
int ret_undo = set_trigger(target, idx, 0, 0, 0);
int ret_undo = set_trigger(target, idx, 0, 0);
if (ret_undo != ERROR_OK)
return ret_undo;

Expand Down Expand Up @@ -918,7 +953,6 @@ struct match_triggers_tdata1_fields {
riscv_reg_t ge;
riscv_reg_t eq;
} match;
riscv_reg_t tdata1_ignore_mask;
};

static struct match_triggers_tdata1_fields fill_match_triggers_tdata1_fields_t2(struct target *target,
Expand Down Expand Up @@ -951,8 +985,7 @@ static struct match_triggers_tdata1_fields fill_match_triggers_tdata1_fields_t2(
.lt = field_value(CSR_MCONTROL_MATCH, CSR_MCONTROL_MATCH_LT),
.ge = field_value(CSR_MCONTROL_MATCH, CSR_MCONTROL_MATCH_GE),
.eq = field_value(CSR_MCONTROL_MATCH, CSR_MCONTROL_MATCH_EQUAL)
},
.tdata1_ignore_mask = CSR_MCONTROL_MASKMAX(riscv_xlen(target))
}
};
return result;
}
Expand Down Expand Up @@ -989,8 +1022,7 @@ static struct match_triggers_tdata1_fields fill_match_triggers_tdata1_fields_t6(
.lt = field_value(CSR_MCONTROL6_MATCH, CSR_MCONTROL6_MATCH_LT),
.ge = field_value(CSR_MCONTROL6_MATCH, CSR_MCONTROL6_MATCH_GE),
.eq = field_value(CSR_MCONTROL6_MATCH, CSR_MCONTROL6_MATCH_EQUAL)
},
.tdata1_ignore_mask = 0
}
};
return result;
}
Expand All @@ -1009,8 +1041,7 @@ static int maybe_add_trigger_t2_t6_for_wp(struct target *target,
struct trigger_request_info napot = {
.tdata1 = fields.common | fields.size.any |
fields.chain.disable | fields.match.napot,
.tdata2 = trigger->address | ((trigger->length - 1) >> 1),
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address | ((trigger->length - 1) >> 1)
};
ret = try_setup_single_match_trigger(target, trigger, napot);
if (ret != ERROR_TARGET_RESOURCE_NOT_AVAILABLE)
Expand All @@ -1026,14 +1057,12 @@ static int maybe_add_trigger_t2_t6_for_wp(struct target *target,
struct trigger_request_info ge_1 = {
.tdata1 = fields.common | fields.size.any | fields.chain.enable |
fields.match.ge,
.tdata2 = trigger->address,
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address
};
struct trigger_request_info lt_2 = {
.tdata1 = fields.common | fields.size.any | fields.chain.disable |
fields.match.lt,
.tdata2 = trigger->address + trigger->length,
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address + trigger->length
};
ret = try_setup_chained_match_triggers(target, trigger, ge_1, lt_2);
if (ret != ERROR_TARGET_RESOURCE_NOT_AVAILABLE)
Expand All @@ -1043,14 +1072,12 @@ static int maybe_add_trigger_t2_t6_for_wp(struct target *target,
struct trigger_request_info lt_1 = {
.tdata1 = fields.common | fields.size.any | fields.chain.enable |
fields.match.lt,
.tdata2 = trigger->address + trigger->length,
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address + trigger->length
};
struct trigger_request_info ge_2 = {
.tdata1 = fields.common | fields.size.any | fields.chain.disable |
fields.match.ge,
.tdata2 = trigger->address,
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address
};
ret = try_setup_chained_match_triggers(target, trigger, lt_1, ge_2);
if (ret != ERROR_TARGET_RESOURCE_NOT_AVAILABLE)
Expand All @@ -1066,8 +1093,7 @@ static int maybe_add_trigger_t2_t6_for_wp(struct target *target,
struct trigger_request_info eq = {
.tdata1 = fields.common | fields.size.any | fields.chain.disable |
fields.match.eq,
.tdata2 = trigger->address,
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address
};
ret = try_setup_single_match_trigger(target, trigger, eq);
if (ret != ERROR_OK)
Expand Down Expand Up @@ -1104,8 +1130,7 @@ static int maybe_add_trigger_t2_t6_for_bp(struct target *target,
struct trigger_request_info eq = {
.tdata1 = fields.common | fields.size.any | fields.chain.disable |
fields.match.eq,
.tdata2 = trigger->address,
.tdata1_ignore_mask = fields.tdata1_ignore_mask
.tdata2 = trigger->address
};

return try_setup_single_match_trigger(target, trigger, eq);
Expand Down Expand Up @@ -1148,7 +1173,7 @@ static int maybe_add_trigger_t3(struct target *target, bool vs, bool vu,
ret = find_next_free_trigger(target, CSR_TDATA1_TYPE_ICOUNT, false, &idx);
if (ret != ERROR_OK)
return ret;
ret = set_trigger(target, idx, tdata1, 0, 0);
ret = set_trigger(target, idx, tdata1, 0);
if (ret != ERROR_OK)
return ret;
r->trigger_unique_id[idx] = unique_id;
Expand Down Expand Up @@ -1181,7 +1206,7 @@ static int maybe_add_trigger_t4(struct target *target, bool vs, bool vu,
ret = find_next_free_trigger(target, CSR_TDATA1_TYPE_ITRIGGER, false, &idx);
if (ret != ERROR_OK)
return ret;
ret = set_trigger(target, idx, tdata1, tdata2, 0);
ret = set_trigger(target, idx, tdata1, tdata2);
if (ret != ERROR_OK)
return ret;
r->trigger_unique_id[idx] = unique_id;
Expand Down Expand Up @@ -1213,7 +1238,7 @@ static int maybe_add_trigger_t5(struct target *target, bool vs, bool vu,
ret = find_next_free_trigger(target, CSR_TDATA1_TYPE_ETRIGGER, false, &idx);
if (ret != ERROR_OK)
return ret;
ret = set_trigger(target, idx, tdata1, tdata2, 0);
ret = set_trigger(target, idx, tdata1, tdata2);
if (ret != ERROR_OK)
return ret;
r->trigger_unique_id[idx] = unique_id;
Expand Down