perf: Handle compat ioctl
commit b3f207855f
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>
This commit is contained in:
parent
d07dd9bce7
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@ -39,6 +39,7 @@
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#include <linux/hw_breakpoint.h>
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#include <linux/mm_types.h>
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#include <linux/cgroup.h>
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#include <linux/compat.h>
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#include "internal.h"
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@ -3693,6 +3694,26 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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return 0;
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}
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#ifdef CONFIG_COMPAT
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static long perf_compat_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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switch (_IOC_NR(cmd)) {
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case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
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case _IOC_NR(PERF_EVENT_IOC_ID):
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/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
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if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
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cmd &= ~IOCSIZE_MASK;
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cmd |= sizeof(void *) << IOCSIZE_SHIFT;
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}
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break;
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}
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return perf_ioctl(file, cmd, arg);
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}
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#else
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# define perf_compat_ioctl NULL
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#endif
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int perf_event_task_enable(void)
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{
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struct perf_event *event;
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@ -4185,7 +4206,7 @@ static const struct file_operations perf_fops = {
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.read = perf_read,
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.poll = perf_poll,
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.unlocked_ioctl = perf_ioctl,
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.compat_ioctl = perf_ioctl,
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.compat_ioctl = perf_compat_ioctl,
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.mmap = perf_mmap,
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.fasync = perf_fasync,
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};
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