tools headers UAPI: Sync linux/fscrypt.h with the kernel sources

tldr; Just FYI, I'm carrying this on the perf tools tree.

- Arnaldo

Full explanation:

There used to be no copies, with tools/ code using kernel headers directly. From time to time tools/perf/ broke due to legitimate kernel hacking. At some point Linus complained about such direct usage. Then we adopted the current model.

The way these headers are used in perf are not restricted to just including them to compile something.

There are sometimes used in scripts that convert defines into string tables, etc, so some change may break one of these scripts, or new MSRs may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
  	[0] = "NORMAL",
  	[1] = "RANDOM",
  	[2] = "SEQUENTIAL",
  	[3] = "WILLNEED",
  	[4] = "DONTNEED",
  	[5] = "NOREUSE",
  };
  $
  $ tools/perf/trace/beauty/sync_file_range.sh
  static const char *sync_file_range_flags[] = {
	  [ilog2(1) + 1] = "WAIT_BEFORE",
	  [ilog2(2) + 1] = "WRITE",
	  [ilog2(4) + 1] = "WAIT_AFTER",
  };

The tools/perf/check-headers.sh script, part of the tools/ build process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in the original kernel headers, that will be done later, when check-headers.sh inform about the change to the perf tools hackers.

---

To pick the changes from:

6b2a51ff03bf0c54 ("fscrypt: Add HCTR2 support for filename encryption")

That don't result in any changes in tooling, just causes this to be rebuilt:

CC /tmp/build/perf-urgent/trace/beauty/sync_file_range.o
LD /tmp/build/perf-urgent/trace/beauty/perf-in.o

addressing this perf build warning:

Warning: Kernel ABI header at 'tools/include/uapi/linux/fscrypt.h' differs from latest version at 'include/uapi/linux/fscrypt.h' diff -u tools/include/uapi/linux/fscrypt.h include/uapi/linux/fscrypt.h

---
 tools/include/uapi/linux/fscrypt.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 9f4428be3e362668..a756b29afcc23749 100644
@@ -27,7 +27,8 @@
 #define FSCRYPT_MODE_AES_128_CBC		5
 #define FSCRYPT_MODE_AES_128_CTS		6
 #define FSCRYPT_MODE_ADIANTUM			9
-/* If adding a mode number > 9, update FSCRYPT_MODE_MAX in fscrypt_private.h */
+#define FSCRYPT_MODE_AES_256_HCTR2		10
+/* If adding a mode number > 10, update FSCRYPT_MODE_MAX in fscrypt_private.h */
 
 /*
  * Legacy policy version; ad-hoc KDF and no key verification.

2.37.1