[PATCH v2 4/4] lib: sbi: Clear lock only for local events

[Clément Léger]

Upon hart reset, only the local events state should be reset. While this
implicitely worked since fwft_get_feature() return NULL for global
events this is a bit fragile to do so. Additionally, the loop on feature
list plus the call to fwft_get_feature was unneeded since we already have
a direct access to the fwft hart state and thus can directly reset lock
flags for each config. Lastly, we can only clear the lock when the fwft
hart state was already allocated, in the other case, it is allocated with
a zalloc which guarantees us that the feature flags are clear at boot.

Signed-off-by: Clément Léger <cleger at rivosinc.com>
---
 lib/sbi/sbi_fwft.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c
index 85f8a638..d946e9db 100644
--- a/lib/sbi/sbi_fwft.c
+++ b/lib/sbi/sbi_fwft.c
@@ -271,12 +271,17 @@ static int fwft_get_pmlen(struct fwft_config *conf, unsigned long *value)
 }
 #endif
 
+static bool fwft_feature_is_global(enum sbi_fwft_feature_t feature)
+{
+	return feature & SBI_FWFT_GLOBAL_FEATURE_BIT;
+}
+
 static struct fwft_config* get_feature_config(enum sbi_fwft_feature_t feature)
 {
 	int i;
 	struct fwft_hart_state *fhs = fwft_thishart_state_ptr();
 
-	if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT)
+	if (fwft_feature_is_global(feature))
 		return NULL;
 
 	for (i = 0; i < fhs->config_count; i++){
@@ -315,16 +320,18 @@ static int fwft_get_feature(unsigned long feature,
 	return SBI_SUCCESS;
 }
 
-static void fwft_clear_config_lock(enum sbi_fwft_feature_t feature)
+static void fwft_clear_local_lock(struct fwft_hart_state *fhs)
 {
-	int ret;
+	int i;
 	struct fwft_config *conf;
 
-	ret = fwft_get_feature(feature, &conf);
-	if (ret)
-		return;
+	for (i = 0; i < fhs->config_count; i++) {
+		conf = &fhs->configs[i];
+		if (fwft_feature_is_global(conf->feature->id))
+			continue;
 
-	conf->flags &= ~SBI_FWFT_SET_FLAG_LOCK;
+		conf->flags &= ~SBI_FWFT_SET_FLAG_LOCK;
+	}
 }
 
 int sbi_fwft_set(unsigned long feature, unsigned long value,
@@ -428,10 +435,9 @@ int sbi_fwft_init(struct sbi_scratch *scratch, bool cold_boot)
 			fhs->configs[i].feature = &features[i];
 
 		fwft_set_hart_state_ptr(scratch, fhs);
+	} else {
+		fwft_clear_local_lock(fhs);
 	}
 
-	for (i = 0; i < array_size(features); i++)
-		fwft_clear_config_lock(features[i].id);
-
 	return 0;
 }
-- 
2.47.1