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>
diff --git a/cpu.c b/cpu.c
index 945dd3d..016bf06 100644
--- a/cpu.c
+++ b/cpu.c
@@ -174,13 +174,23 @@
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 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 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. The default if no link is set up is to use
* the system address space.
*/
DEFINE_PROP_LINK("memory", CPUState, memory, TYPE_MEMORY_REGION,
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index e948e81..76ab3b8 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -413,6 +413,9 @@
bool ignore_memory_transaction_failures;
+ /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */
+ bool prctl_unalign_sigbus;
+
struct hax_vcpu_state *hax_vcpu;
struct hvf_vcpu_state *hvf;
diff --git a/linux-user/generic/target_prctl_unalign.h b/linux-user/generic/target_prctl_unalign.h
new file mode 100644
index 0000000..bc3b83a
--- /dev/null
+++ b/linux-user/generic/target_prctl_unalign.h
@@ -0,0 +1,27 @@
+/*
+ * Generic prctl unalign functions for linux-user
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef GENERIC_TARGET_PRCTL_UNALIGN_H
+#define GENERIC_TARGET_PRCTL_UNALIGN_H
+
+static abi_long do_prctl_get_unalign(CPUArchState *env, target_long arg2)
+{
+ CPUState *cs = env_cpu(env);
+ uint32_t res = PR_UNALIGN_NOPRINT;
+ if (cs->prctl_unalign_sigbus) {
+ res |= PR_UNALIGN_SIGBUS;
+ }
+ return put_user_u32(res, arg2);
+}
+#define do_prctl_get_unalign do_prctl_get_unalign
+
+static abi_long do_prctl_set_unalign(CPUArchState *env, target_long arg2)
+{
+ env_cpu(env)->prctl_unalign_sigbus = arg2 & PR_UNALIGN_SIGBUS;
+ return 0;
+}
+#define do_prctl_set_unalign do_prctl_set_unalign
+
+#endif /* GENERIC_TARGET_PRCTL_UNALIGN_H */
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d868ef2..b511289 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6378,6 +6378,12 @@
#ifndef do_prctl_get_tagged_addr_ctrl
#define do_prctl_get_tagged_addr_ctrl do_prctl_inval0
#endif
+#ifndef do_prctl_get_unalign
+#define do_prctl_get_unalign do_prctl_inval1
+#endif
+#ifndef do_prctl_set_unalign
+#define do_prctl_set_unalign do_prctl_inval1
+#endif
static abi_long do_prctl(CPUArchState *env, abi_long option, abi_long arg2,
abi_long arg3, abi_long arg4, abi_long arg5)
@@ -6441,6 +6447,11 @@
}
return do_prctl_get_tagged_addr_ctrl(env);
+ case PR_GET_UNALIGN:
+ return do_prctl_get_unalign(env, arg2);
+ case PR_SET_UNALIGN:
+ return do_prctl_set_unalign(env, arg2);
+
case PR_GET_DUMPABLE:
case PR_SET_DUMPABLE:
case PR_GET_KEEPCAPS:
@@ -6483,8 +6494,6 @@
case PR_SET_THP_DISABLE:
case PR_GET_TSC:
case PR_SET_TSC:
- case PR_GET_UNALIGN:
- case PR_SET_UNALIGN:
/* Disable to prevent the target disabling stuff we need. */
return -TARGET_EINVAL;
