[PATCH v4 06/15] futex2: Add compatibility entry point for x86_x32 ABI

From: "André Almeida" <andrealmeid@collabora.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Darren Hart <dvhart@infradead.org>,
	linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: kernel@collabora.com, krisman@collabora.com,
	pgriffais@valvesoftware.com, z.figura12@gmail.com,
	joel@joelfernandes.org, malteskarupke@fastmail.fm,
	linux-api@vger.kernel.org, fweimer@redhat.com,
	libc-alpha@sourceware.org, linux-kselftest@vger.kernel.org,
	shuah@kernel.org, acme@kernel.org, corbet@lwn.net,
	"Peter Oskolkov" <posk@posk.io>,
	"Andrey Semashev" <andrey.semashev@gmail.com>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"André Almeida" <andrealmeid@collabora.com>
Subject: [PATCH v4 06/15] futex2: Add compatibility entry point for x86_x32 ABI
Date: Thu,  3 Jun 2021 16:59:15 -0300	[thread overview]
Message-ID: <20210603195924.361327-7-andrealmeid@collabora.com> (raw)
In-Reply-To: <20210603195924.361327-1-andrealmeid@collabora.com>

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 <andrealmeid@collabora.com>
---
 kernel/futex2.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/kernel/futex2.c b/kernel/futex2.c
index 1e97e5f2e793..5fd0b3d73b53 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
@@ -910,7 +914,16 @@ 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_waitv(futexv, nr_futexes, timo, flags);
 
@@ -1215,6 +1228,27 @@ SYSCALL_DEFINE6(futex_requeue, struct futex_requeue __user *, uaddr1,
 	if (ret)
 		return ret;
 
+#ifdef CONFIG_X86_X32_ABI
+	if (in_x32_syscall()) {
+		ret = compat_futex_parse_requeue(&rq1, (struct compat_futex_requeue *)uaddr1);
+		if (ret)
+			return ret;
+
+		ret = compat_futex_parse_requeue(&rq2, (struct compat_futex_requeue *)uaddr2);
+		if (ret)
+			return ret;
+	} else
+#endif
+	{
+		ret = futex_parse_requeue(&rq1, uaddr1);
+		if (ret)
+			return ret;
+
+		ret = futex_parse_requeue(&rq2, uaddr2);
+		if (ret)
+			return ret;
+	}
+
 	return __futex_requeue(rq1, rq2, nr_wake, nr_requeue, cmpval);
 }
 
-- 
2.31.1

