libmicrokit: add func to get mr count from msginfo

Signed-off-by: Krishnan Winter <[email protected]>
seL4 · Apr 26, 2024 · 744e2ca · 744e2ca
1 parent c2cfd9a
commit 744e2ca
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diff --git a/docs/manual.md b/docs/manual.md
@@ -353,6 +353,7 @@ Additionally, if the protection domain provides a protected procedure it must al
     void microkit_notify(microkit_channel ch);
     microkit_msginfo microkit_msginfo_new(uint64_t label, uint16_t count);
     uint64_t microkit_msginfo_get_label(microkit_msginfo msginfo);
+    uint64_t microkit_msginfo_get_count(microkit_msginfo msginfo);
     void microkit_irq_ack(microkit_channel ch);
     void microkit_mr_set(uint8_t mr, uint64_t value);
     uint64_t microkit_mr_get(uint8_t mr);
@@ -421,6 +422,10 @@ The message can be passed to `microkit_ppcall` or returned from `protected`.
 
 Returns the label from a message.
 
+## `uint64_t microkit_msginfo_get_count(microkit_msginfo msginfo)`
+
+Returns the count of message registers in the message.
+
 ## `uint64_t microkit_mr_get(uint8_t mr)`
 
 Get a message register.

diff --git a/libmicrokit/include/microkit.h b/libmicrokit/include/microkit.h
@@ -75,6 +75,12 @@ microkit_msginfo_get_label(microkit_msginfo msginfo)
     return seL4_MessageInfo_get_label(msginfo);
 }
 
+static inline uint64_t
+microkit_msginfo_get_count(microkit_msginfo msginfo)
+{
+    return seL4_MessageInfo_get_length(msginfo);
+}
+
 static void
 microkit_mr_set(uint8_t mr, uint64_t value)
 {