At the same time, split out set_robust_list and get_robust_list.
Put them together, along with their block comment, at the top
of syscall_table.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
linux-user/syscall.c | 87 +++++++++++++++++++++++++++++++++-----------
1 file changed, 66 insertions(+), 21 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 46f123ee13..8678e749ee 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7947,6 +7947,17 @@ static int host_to_target_cpu_mask(const unsigned long
*host_mask,
return 0;
}
+typedef abi_long impl_fn(void *cpu_env, unsigned num, abi_long arg1,
+ abi_long arg2, abi_long arg3, abi_long arg4,
+ abi_long arg5, abi_long arg6, abi_long arg7,
+ abi_long arg8);
+
+#define IMPL(NAME) \
+static abi_long impl_##NAME(void *cpu_env, unsigned num, abi_long arg1, \
+ abi_long arg2, abi_long arg3, abi_long arg4, \
+ abi_long arg5, abi_long arg6, abi_long arg7, \
+ abi_long arg8)
+
/* This is an internal helper for do_syscall so that it is easier
* to have a single return point, so that actions, such as logging
* of syscall results, can be performed.
@@ -11740,23 +11751,6 @@ static abi_long do_syscall1(void *cpu_env, unsigned
num, abi_long arg1,
return get_errno(safe_tgkill((int)arg1, (int)arg2,
target_to_host_signal(arg3)));
-#ifdef TARGET_NR_set_robust_list
- case TARGET_NR_set_robust_list:
- case TARGET_NR_get_robust_list:
- /* The ABI for supporting robust futexes has userspace pass
- * the kernel a pointer to a linked list which is updated by
- * userspace after the syscall; the list is walked by the kernel
- * when the thread exits. Since the linked list in QEMU guest
- * memory isn't a valid linked list for the host and we have
- * no way to reliably intercept the thread-death event, we can't
- * support these. Silently return ENOSYS so that guest userspace
- * falls back to a non-robust futex implementation (which should
- * be OK except in the corner case of the guest crashing while
- * holding a mutex that is shared with another process via
- * shared memory).
- */
- return -TARGET_ENOSYS;
-#endif
#if defined(TARGET_NR_utimensat)
case TARGET_NR_utimensat:
@@ -12412,6 +12406,54 @@ static abi_long do_syscall1(void *cpu_env, unsigned
num, abi_long arg1,
return ret;
}
+/* The default action for a syscall not listed in syscall_table is to
+ * log the missing syscall. If a syscall is intentionally emulated as
+ * not present, then list it with impl_enosys as the implementation,
+ * which will avoid the logging.
+ */
+IMPL(enosys)
+{
+ return -TARGET_ENOSYS;
+}
+
+/* For a given syscall number, return a function implementing it.
+ * Do this via switch statement instead of table because some targets
+ * do not begin at 0 and others have a large split in the middle of
+ * the numbers. The compiler should be able to produce a dense table.
+ */
+static impl_fn *syscall_table(unsigned num)
+{
+#define SYSCALL_WITH(X, Y) case TARGET_NR_##X: return impl_##Y
+#define SYSCALL(X) SYSCALL_WITH(X, X)
+
+ switch (num) {
+ /* The ABI for supporting robust futexes has userspace pass
+ * the kernel a pointer to a linked list which is updated by
+ * userspace after the syscall; the list is walked by the kernel
+ * when the thread exits. Since the linked list in QEMU guest
+ * memory isn't a valid linked list for the host and we have
+ * no way to reliably intercept the thread-death event, we can't
+ * support these. Silently return ENOSYS so that guest userspace
+ * falls back to a non-robust futex implementation (which should
+ * be OK except in the corner case of the guest crashing while
+ * holding a mutex that is shared with another process via
+ * shared memory).
+ */
+ SYSCALL_WITH(get_robust_list, enosys);
+ SYSCALL_WITH(set_robust_list, enosys);
+
+ /*
+ * Other syscalls listed in collation order, with '_' ignored.
+ */
+ }
+
+#undef SYSCALL
+#undef SYSCALL_WITH
+
+ /* After do_syscall1 is fully split, this will be impl_enosys. */
+ return do_syscall1;
+}
+
abi_long do_syscall(void *cpu_env, unsigned num, abi_long arg1,
abi_long arg2, abi_long arg3, abi_long arg4,
abi_long arg5, abi_long arg6, abi_long arg7,
@@ -12419,6 +12461,7 @@ abi_long do_syscall(void *cpu_env, unsigned num,
abi_long arg1,
{
CPUState *cpu = ENV_GET_CPU(cpu_env);
abi_long ret;
+ impl_fn *fn;
#ifdef DEBUG_ERESTARTSYS
/* Debug-only code for exercising the syscall-restart code paths
@@ -12437,14 +12480,16 @@ abi_long do_syscall(void *cpu_env, unsigned num,
abi_long arg1,
trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4,
arg5, arg6, arg7, arg8);
+ fn = syscall_table(num);
+
if (unlikely(do_strace)) {
print_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
- ret = do_syscall1(cpu_env, num, arg1, arg2, arg3, arg4,
- arg5, arg6, arg7, arg8);
+ ret = fn(cpu_env, num, arg1, arg2, arg3, arg4,
+ arg5, arg6, arg7, arg8);
print_syscall_ret(num, ret);
} else {
- ret = do_syscall1(cpu_env, num, arg1, arg2, arg3, arg4,
- arg5, arg6, arg7, arg8);
+ ret = fn(cpu_env, num, arg1, arg2, arg3, arg4,
+ arg5, arg6, arg7, arg8);
}
trace_guest_user_syscall_ret(cpu, num, ret);
--
2.17.1
