# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1654447791 -7200
# Node ID a34ea5ec49f32814c36c93368462fb38304204cc
# Parent  7ac27a50d236e0c47ae350c0a9c511bba34eba4d
Introduced some support for specifying receive window flexpages.

diff -r 7ac27a50d236 -r a34ea5ec49f3 libipc/include/ipc/message.h
--- a/libipc/include/ipc/message.h	Sun Jun 05 18:48:38 2022 +0200
+++ b/libipc/include/ipc/message.h	Sun Jun 05 18:49:51 2022 +0200
@@ -1,7 +1,7 @@
 /*
  * Interprocess communication message abstraction.
  *
- * Copyright (C) 2018, 2019, 2021 Paul Boddie <paul@boddie.org.uk>
+ * Copyright (C) 2018, 2019, 2021, 2022 Paul Boddie <paul@boddie.org.uk>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -46,6 +46,10 @@
   l4_msgtag_t tag;
   unsigned int expected_items;
 
+  /* Receive item counter. */
+
+  unsigned int receive_items;
+
   /* Output details. */
 
   unsigned int words;
@@ -109,6 +113,7 @@
 void ipc_message_add_item(ipc_message_t *msg, l4_cap_idx_t cap);
 void ipc_message_add_fpage(ipc_message_t *msg, l4_snd_fpage_t fpage);
 void ipc_message_add_page(ipc_message_t *msg, l4_umword_t hot_spot, l4_fpage_t fpage);
+void ipc_message_add_receive_fpage(ipc_message_t *msg, l4_snd_fpage_t fpage);
 void ipc_message_add_string(ipc_message_t *msg, const char *value);
 void ipc_message_add_word(ipc_message_t *msg, l4_umword_t value);
 void ipc_message_propagate_item(ipc_message_t *msg, l4_cap_idx_t cap);
@@ -136,6 +141,7 @@
 long ipc_message_import_dataspace(ipc_message_t *msg, int item, l4re_ds_t *mem, l4_addr_t *addr);
 long ipc_message_import_fpage(ipc_message_t *msg, int item, l4_snd_fpage_t *fpage);
 void ipc_message_propagate_capability(ipc_message_t *msg, int item, l4_cap_idx_t ref);
+void ipc_message_receive_fpage(ipc_message_t *msg, int item, l4_snd_fpage_t fpage);
 l4_msgtag_t ipc_message_reply_tag(ipc_message_t *msg);
 l4_msgtag_t ipc_message_request_tag(ipc_message_t *msg, int op);
 
diff -r 7ac27a50d236 -r a34ea5ec49f3 libipc/lib/src/message.c
--- a/libipc/lib/src/message.c	Sun Jun 05 18:48:38 2022 +0200
+++ b/libipc/lib/src/message.c	Sun Jun 05 18:49:51 2022 +0200
@@ -1,7 +1,7 @@
 /*
  * Interprocess communication message abstraction.
  *
- * Copyright (C) 2018, 2019, 2021 Paul Boddie <paul@boddie.org.uk>
+ * Copyright (C) 2018, 2019, 2021, 2022 Paul Boddie <paul@boddie.org.uk>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -71,6 +71,7 @@
   /* Set a default for expected items. */
 
   msg->expected_items = 0;
+  msg->receive_items = 0;
   ipc_message_reset(msg);
 }
 
@@ -97,8 +98,13 @@
 
   msg->bregs.bdr = bregs->bdr;
 
-  for (i = 0; i < msg->expected_items; i++)
-    msg->bregs.br[i] = bregs->br[i];
+  /* NOTE: Support a mixture of expected items and received flexpages. */
+
+  if ((msg->expected_items) || (msg->receive_items))
+  {
+    for (i = 0; (i < msg->expected_items) || (i < msg->receive_items * 2); i++)
+      msg->bregs.br[i] = bregs->br[i];
+  }
 }
 
 /* Preserve the message registers. */
@@ -142,8 +148,13 @@
 
   bregs->bdr = msg->bregs.bdr;
 
-  for (i = 0; i < msg->expected_items; i++)
-    bregs->br[i] = msg->bregs.br[i];
+  /* NOTE: Support a mixture of expected items and received flexpages. */
+
+  if ((msg->expected_items) || (msg->receive_items))
+  {
+    for (i = 0; (i < msg->expected_items) || (i < msg->receive_items * 2); i++)
+      bregs->br[i] = msg->bregs.br[i];
+  }
 }
 
 /* Restore message registers to communicate recorded data and items. */
@@ -246,6 +257,13 @@
   ipc_message_export_fpage(msg, msg->items++, fpage);
 }
 
+/* Add a receive window flexpage item to the message. */
+
+void ipc_message_add_receive_fpage(ipc_message_t *msg, l4_snd_fpage_t fpage)
+{
+  ipc_message_receive_fpage(msg, msg->receive_items++, fpage);
+}
+
 /* Add a flexpage to the message. */
 
 void ipc_message_add_page(ipc_message_t *msg, l4_umword_t hot_spot,
@@ -433,6 +451,16 @@
   msg->mregs.mr[msg->words + item * 2 + 1] = fpage.raw;
 }
 
+/* Specify a receive window flexpage item in the message. */
+
+void ipc_message_receive_fpage(ipc_message_t *msg, int item, l4_snd_fpage_t fpage)
+{
+  msg->bregs.br[item * 2] = l4_map_control(fpage.snd_base, 0, 0);
+  msg->bregs.br[item * 2 + 1] = fpage.fpage.raw;
+}
+
+
+
 /* Import from the message the capability at the given item position, updating
    the buffer registers for future capabilities. */
 
@@ -475,3 +503,6 @@
   ipc_message_export_capability(msg, item, ref);
   ipc_message_discard_capability(msg, ref);
 }
+
+/* vim: tabstop=2 expandtab shiftwidth=2
+*/
diff -r 7ac27a50d236 -r a34ea5ec49f3 libipc/lib/src/util_ipc.c
--- a/libipc/lib/src/util_ipc.c	Sun Jun 05 18:48:38 2022 +0200
+++ b/libipc/lib/src/util_ipc.c	Sun Jun 05 18:49:51 2022 +0200
@@ -30,7 +30,9 @@
 
 
 
-/* Declare expected capabilities. */
+/* Declare expected capabilities.
+   NOTE: This does not support the mixing of expected capabilities and other
+         items. */
 
 long _expect_capabilities(l4_buf_regs_t *bregs, int number)
 {
@@ -233,3 +235,6 @@
 {
   return l4_ipc_send(endpoint, l4_utcb(), tag, L4_IPC_NEVER);
 }
+
+/* vim: tabstop=2 expandtab shiftwidth=2
+*/