linux-user: Add code for PR_GET/SET_UNALIGN

This requires extra work for each target, but adds the
common syscall code, and the necessary flag in CPUState.

Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211227150127.2659293-4-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

1 files changed, 15 insertions, 5 deletions

diff --git a/cpu.c b/cpu.c
index 945dd3dded..016bf06a1a 100644
--- a/cpu.c
+++ b/cpu.c
@@ -174,13 +174,23 @@ void cpu_exec_unrealizefn(CPUState *cpu)
     cpu_list_remove(cpu);
 }
 
+/*
+ * This can't go in hw/core/cpu.c because that file is compiled only
+ * once for both user-mode and system builds.
+ */
 static Property cpu_common_props[] = {
-#ifndef CONFIG_USER_ONLY
+#ifdef CONFIG_USER_ONLY
+    /*
+     * Create a property for the user-only object, so users can
+     * adjust prctl(PR_SET_UNALIGN) from the command-line.
+     * Has no effect if the target does not support the feature.
+     */
+    DEFINE_PROP_BOOL("prctl-unalign-sigbus", CPUState,
+                     prctl_unalign_sigbus, false),
+#else
     /*
-     * Create a memory property for softmmu CPU object,
-     * so users can wire up its memory. (This can't go in hw/core/cpu.c
-     * because that file is compiled only once for both user-mode
-     * and system builds.) The default if no link is set up is to use
+     * Create a memory property for softmmu CPU object, so users can
+     * wire up its memory.  The default if no link is set up is to use
      * the system address space.
      */
     DEFINE_PROP_LINK("memory", CPUState, memory, TYPE_MEMORY_REGION,