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authorPawel Moll <pawel.moll@arm.com>2014-06-13 16:03:32 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-21 09:23:05 -0800
commite252f74ecd88f9c4d7a1b14cfcb5bb93c517c118 (patch)
tree5834693c0d88073ce8abcb2968080fd0b945112f /kernel/events
parentd07dd9bce7b90980393cecd372b08600e0f345de (diff)
perf: Handle compat ioctl
commit b3f207855f57b9c8f43a547a801340bb5cbc59e5 upstream. When running a 32-bit userspace on a 64-bit kernel (eg. i386 application on x86_64 kernel or 32-bit arm userspace on arm64 kernel) some of the perf ioctls must be treated with special care, as they have a pointer size encoded in the command. For example, PERF_EVENT_IOC_ID in 32-bit world will be encoded as 0x80042407, but 64-bit kernel will expect 0x80082407. In result the ioctl will fail returning -ENOTTY. This patch solves the problem by adding code fixing up the size as compat_ioctl file operation. Reported-by: Drew Richardson <drew.richardson@arm.com> Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/r/1402671812-9078-1-git-send-email-pawel.moll@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: David Ahern <daahern@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4ced342f1ba9..4bbb27adf23d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -39,6 +39,7 @@
#include <linux/hw_breakpoint.h>
#include <linux/mm_types.h>
#include <linux/cgroup.h>
+#include <linux/compat.h>
#include "internal.h"
@@ -3693,6 +3694,26 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return 0;
}
+#ifdef CONFIG_COMPAT
+static long perf_compat_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ switch (_IOC_NR(cmd)) {
+ case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
+ case _IOC_NR(PERF_EVENT_IOC_ID):
+ /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
+ if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
+ cmd &= ~IOCSIZE_MASK;
+ cmd |= sizeof(void *) << IOCSIZE_SHIFT;
+ }
+ break;
+ }
+ return perf_ioctl(file, cmd, arg);
+}
+#else
+# define perf_compat_ioctl NULL
+#endif
+
int perf_event_task_enable(void)
{
struct perf_event *event;
@@ -4185,7 +4206,7 @@ static const struct file_operations perf_fops = {
.read = perf_read,
.poll = perf_poll,
.unlocked_ioctl = perf_ioctl,
- .compat_ioctl = perf_ioctl,
+ .compat_ioctl = perf_compat_ioctl,
.mmap = perf_mmap,
.fasync = perf_fasync,
};