Patchwork [PULL,06/24] configure: Don't allow user-only targets for unknown CPU architectures

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Date June 24, 2016, 9:53 a.m.
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Permalink /patch/39701/
State New
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Comments - June 24, 2016, 9:53 a.m.
From: Peter Maydell <>

For the user-only targets, we need to know something about the host CPU
architecture even if we are using the TCI interpreter rather than TCG.
(In particular user-exec.c has code for handling signals that needs
to know about that host's context structures.)

Specifically forbid building the user-only targets on unknown CPU
architectures, rather than allowing them to configure but then fail
when building user-exec.c.

This change drops supports for two configurations which were theoretically
possible before:
 * linux-user targets on M68K hosts using TCI
 * linux-user targets on HPPA hosts using TCI

We don't think anybody is actually trying to use these in practice, though:
 * interpreted TCG on a slow host CPU would be unusably slow
 * the m68k user-exec.c support is missing is_write detection so guest
   code which writes to the same page it is executing from was broken
   (will include any guest program using signals)
 * HPPA TCG backend support was dropped two and a half years ago
   with no complaints

Signed-off-by: Peter Maydell <>
Reviewed-by: Laurent Vivier <>
Reviewed-by: Richard Henderson <>
Signed-off-by: Riku Voipio <>
 configure | 7 +++++++
 1 file changed, 7 insertions(+)


diff --git a/configure b/configure
index 6696316..dce20f0 100755
--- a/configure
+++ b/configure
@@ -1216,6 +1216,13 @@  esac
+# For user-mode emulation the host arch has to be one we explicitly
+# support, even if we're using TCI.
+if [ "$ARCH" = "unknown" ]; then
+  bsd_user="no"
+  linux_user="no"