# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1664573101 -7200
# Node ID cf0f5adb98264920fbf7c84bb873b086baf5f19a
# Parent  672a5524af3a11bfd7e859ca40412999a98fb8b4
Introduced separate UTCB areas for the region mapper and the main program.

diff -r 672a5524af3a -r cf0f5adb9826 libexec/include/exec/process.h
--- a/libexec/include/exec/process.h	Thu Sep 29 18:15:39 2022 +0200
+++ b/libexec/include/exec/process.h	Fri Sep 30 23:25:01 2022 +0200
@@ -72,10 +72,7 @@
 {
 protected:
   l4_cap_idx_t _task = L4_INVALID_CAP;
-
-  /* UTCB details. */
-
-  l4_addr_t _utcb_start;
+  unsigned int _thread_number;
 
   /* Common and thread environment details. */
 
diff -r 672a5524af3a -r cf0f5adb9826 libexec/lib/src/process.cc
--- a/libexec/lib/src/process.cc	Thu Sep 29 18:15:39 2022 +0200
+++ b/libexec/lib/src/process.cc	Fri Sep 30 23:25:01 2022 +0200
@@ -31,18 +31,18 @@
 
 /* Obtain a flexpage defining the UTCB area location and size in a new task. */
 
-static l4_fpage_t get_utcb_fpage()
+static l4_fpage_t get_utcb_fpage(unsigned int page, unsigned int pages)
 {
   /* UTCB location and size. */
 
-  int utcb_log2size = page_order(Default_max_threads * L4_UTCB_OFFSET);
+  int utcb_log2size = page_order(pages * Default_max_threads * L4_UTCB_OFFSET);
 
   /* Round up to at least one page. */
 
   if (utcb_log2size < L4_PAGESHIFT)
     utcb_log2size = L4_PAGESHIFT;
 
-  return l4_fpage(Utcb_area_start, utcb_log2size, 0);
+  return l4_fpage(Utcb_area_start + page * (1UL << utcb_log2size), utcb_log2size, 0);
 }
 
 
@@ -52,11 +52,7 @@
 
 Process::Process(int reserved_threads)
 {
-  /* Obtain UTCB area details for the task. */
-
-  l4_fpage_t utcb_fpage = get_utcb_fpage();
-
-  _utcb_start = l4_fpage_memaddr(utcb_fpage);
+  _thread_number = 0;
 
   /* Populate the common initial environment for the threads. */
 
@@ -64,8 +60,6 @@
   _env.log              = L4_BASE_LOG_CAP;
   _env.scheduler        = L4_BASE_SCHEDULER_CAP;
   _env.mem_alloc        = L4_EXEC_MA_CAP;
-  _env.utcb_area        = utcb_fpage;
-  _env.first_free_utcb  = l4_fpage_memaddr(utcb_fpage) + reserved_threads * L4_UTCB_OFFSET;
 
   /* Capability details that are updated for each thread. */
 
@@ -96,7 +90,7 @@
   if (l4_is_invalid_cap(_task))
     return -L4_ENOMEM;
 
-  return l4_error(l4_factory_create_task(l4re_env()->factory, _task, _env.utcb_area));
+  return l4_error(l4_factory_create_task(l4re_env()->factory, _task, get_utcb_fpage(0, 2)));
 }
 
 long Process::create_thread(l4_cap_idx_t *thread)
@@ -188,12 +182,19 @@
   if (err)
     return err;
 
+  /* Obtain UTCB area details for the thread. */
+
+  l4_fpage_t utcb_fpage = get_utcb_fpage(_thread_number, 1);
+
+  _env.utcb_area       = utcb_fpage;
+  _env.first_free_utcb = l4_fpage_memaddr(utcb_fpage);
+
   /* Initialise the thread with pager, UTCB and task details. */
 
   l4_thread_control_start();
   l4_thread_control_pager(_env.rm);
   l4_thread_control_exc_handler(_env.rm);
-  l4_thread_control_bind((l4_utcb_t *) _utcb_start, _task);
+  l4_thread_control_bind((l4_utcb_t *) l4_fpage_memaddr(_env.utcb_area), _task);
 
   err = l4_error(l4_thread_control_commit(thread));
 
@@ -228,9 +229,9 @@
   if (err)
     return err;
 
-  /* Select a new address for the next thread. */
+  /* Select a new thread. */
 
-  _utcb_start += L4_UTCB_OFFSET;
+  _thread_number++;
 
   /* Start the thread. */