path: root/include
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authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>2018-07-09 15:51:53 -0400
committerThomas Gleixner <tglx@linutronix.de>2018-07-10 22:18:52 +0200
commitec9c82e03a744e5698bd95eab872855861a821fa (patch)
treef3759e2264ea4d4c77809b3e4a3ff8d6241b39d7 /include
parentrseq: uapi: Update uapi comments (diff)
rseq: uapi: Declare rseq_cs field as union, update includes
Declaring the rseq_cs field as a union between __u64 and two __u32 allows both 32-bit and 64-bit kernels to read the full __u64, and therefore validate that a 32-bit user-space cleared the upper 32 bits, thus ensuring a consistent behavior between native 32-bit kernels and 32-bit compat tasks on 64-bit kernels. Check that the rseq_cs value read is < TASK_SIZE. The asm/byteorder.h header needs to be included by rseq.h, now that it is not using linux/types_32_64.h anymore. Considering that only __32 and __u64 types are declared in linux/rseq.h, the linux/types.h header should always be included for both kernel and user-space code: including stdint.h is just for u64 and u32, which are not used in this header at all. Use copy_from_user()/clear_user() to interact with a 64-bit field, because arm32 does not implement 64-bit __get_user, and ppc32 does not 64-bit get_user. Considering that the rseq_cs pointer does not need to be loaded/stored with single-copy atomicity from the kernel anymore, we can simply use copy_from_user()/clear_user(). Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-api@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Watson <davejwatson@fb.com> Cc: Paul Turner <pjt@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Chris Lameter <cl@linux.com> Cc: Ben Maurer <bmaurer@fb.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Joel Fernandes <joelaf@google.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/20180709195155.7654-5-mathieu.desnoyers@efficios.com
Diffstat (limited to 'include')
1 files changed, 19 insertions, 8 deletions
diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h
index bf4188c13bec..9a402fdb60e9 100644
--- a/include/uapi/linux/rseq.h
+++ b/include/uapi/linux/rseq.h
@@ -10,13 +10,8 @@
* Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
-#ifdef __KERNEL__
-# include <linux/types.h>
-# include <stdint.h>
-#include <linux/types_32_64.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
enum rseq_cpu_id_state {
@@ -111,7 +106,23 @@ struct rseq {
* atomicity semantics. This field should only be updated by the
* thread which registered this data structure. Aligned on 64-bit.
- LINUX_FIELD_u32_u64(rseq_cs);
+ union {
+ __u64 ptr64;
+#ifdef __LP64__
+ __u64 ptr;
+ struct {
+#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN)
+ __u32 padding; /* Initialized to zero. */
+ __u32 ptr32;
+#else /* LITTLE */
+ __u32 ptr32;
+ __u32 padding; /* Initialized to zero. */
+#endif /* ENDIAN */
+ } ptr;
+ } rseq_cs;
* Restartable sequences flags field.