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| author | Pawel Moll <pawel.moll@arm.com> | 2014-06-13 17:03:32 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-08-20 09:42:13 +0200 |
| commit | b3f207855f57b9c8f43a547a801340bb5cbc59e5 (patch) | |
| tree | 81845f485708aec5c07e52e119bb48a2bda5985a | |
| parent | kprobes: Skip kretprobe hit in NMI context to avoid deadlock (diff) | |
| download | linux-b3f207855f57b9c8f43a547a801340bb5cbc59e5.tar.xz linux-b3f207855f57b9c8f43a547a801340bb5cbc59e5.zip | |
perf: Handle compat ioctl
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>
| -rw-r--r-- | kernel/events/core.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1cf24b3e42ec..f9c1ed002dbc 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -41,6 +41,7 @@ #include <linux/cgroup.h> #include <linux/module.h> #include <linux/mman.h> +#include <linux/compat.h> #include "internal.h" @@ -3717,6 +3718,26 @@ 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; @@ -4222,7 +4243,7 @@ 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, }; |