[RFC PATCH 05/13] futex2: Add compatibility entry point for x86_x32 ABI

[André Almeida]

New syscalls should use the same entry point for x86_64 and x86_x32
paths. Add a wrapper for x32 calls to use parse functions that assumes
32bit pointers.

Signed-off-by: André Almeida <andrealm...@collabora.com>
---
 kernel/futex2.c | 42 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/kernel/futex2.c b/kernel/futex2.c
index bad8c183cf9f..8a8b45f98d3b 100644
--- a/kernel/futex2.c
+++ b/kernel/futex2.c
@@ -23,6 +23,10 @@
 #include <linux/syscalls.h>
 #include <uapi/linux/futex.h>
 
+#ifdef CONFIG_X86_64
+#include <linux/compat.h>
+#endif
+
 /**
  * struct futex_key - Components to build unique key for a futex
  * @pointer: Pointer to current->mm or inode's UUID for file backed futexes
@@ -875,7 +879,16 @@ SYSCALL_DEFINE4(futex_waitv, struct futex_waitv __user *, 
waiters,
        futexv->hint = false;
        futexv->task = current;
 
-       ret = futex_parse_waitv(futexv, waiters, nr_futexes);
+#ifdef CONFIG_X86_X32_ABI
+       if (in_x32_syscall()) {
+               ret = compat_futex_parse_waitv(futexv, (struct 
compat_futex_waitv *)waiters,
+                                              nr_futexes);
+       } else
+#endif
+       {
+               ret = futex_parse_waitv(futexv, waiters, nr_futexes);
+       }
+
        if (!ret)
                ret = futex_set_timer_and_wait(futexv, nr_futexes, timo, flags);
 
@@ -1181,13 +1194,28 @@ SYSCALL_DEFINE6(futex_requeue, struct futex_requeue 
__user *, uaddr1,
        if (flags)
                return -EINVAL;
 
-       ret = futex_parse_requeue(&rq1, uaddr1, &shared1);
-       if (ret)
-               return ret;
+#ifdef CONFIG_X86_X32_ABI
+       if (in_x32_syscall()) {
+               ret = compat_futex_parse_requeue(&rq1, (struct 
compat_futex_requeue *)uaddr1,
+                                                &shared1);
+               if (ret)
+                       return ret;
 
-       ret = futex_parse_requeue(&rq2, uaddr2, &shared2);
-       if (ret)
-               return ret;
+               ret = compat_futex_parse_requeue(&rq2, (struct 
compat_futex_requeue *)uaddr2,
+                                                &shared2);
+               if (ret)
+                       return ret;
+       } else
+#endif
+       {
+               ret = futex_parse_requeue(&rq1, uaddr1, &shared1);
+               if (ret)
+                       return ret;
+
+               ret = futex_parse_requeue(&rq2, uaddr2, &shared2);
+               if (ret)
+                       return ret;
+       }
 
        return __futex_requeue(rq1, rq2, nr_wake, nr_requeue, cmpval, shared1, 
shared2);
 }
-- 
2.30.1