semihosting: Initialize heap once per process

While semihosting isn't really thread aware, the current
implementation allocates space for the heap per-thread.

Remove the heap_base and heap_limit fields from TaskState.
Replace with static variables within do_common_semihosting.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 9 insertions, 13 deletions

diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index bc04b02eba..bcd13cd6df 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -666,7 +666,7 @@ void do_common_semihosting(CPUState *cs)
             int i;
 #ifdef CONFIG_USER_ONLY
             TaskState *ts = get_task_state(cs);
-            target_ulong limit;
+            static abi_ulong heapbase, heaplimit;
 #else
             LayoutInfo info = common_semi_find_bases(cs);
 #endif
@@ -678,24 +678,20 @@ void do_common_semihosting(CPUState *cs)
              * Some C libraries assume the heap immediately follows .bss, so
              * allocate it using sbrk.
              */
-            if (!ts->heap_limit) {
-                abi_ulong ret;
-
-                ts->heap_base = do_brk(0);
-                limit = ts->heap_base + COMMON_SEMI_HEAP_SIZE;
+            if (!heaplimit) {
+                heapbase = do_brk(0);
                 /* Try a big heap, and reduce the size if that fails.  */
-                for (;;) {
-                    ret = do_brk(limit);
+                for (abi_ulong size = COMMON_SEMI_HEAP_SIZE; ; size >>= 1) {
+                    abi_ulong limit = heapbase + size;
+                    abi_ulong ret = do_brk(limit);
                     if (ret >= limit) {
+                        heaplimit = limit;
                         break;
                     }
-                    limit = (ts->heap_base >> 1) + (limit >> 1);
                 }
-                ts->heap_limit = limit;
             }
-
-            retvals[0] = ts->heap_base;
-            retvals[1] = ts->heap_limit;
+            retvals[0] = heapbase;
+            retvals[1] = heaplimit;
             /*
              * Note that semihosting is *not* thread aware.
              * Always return the stack base of the main thread.