pgo: rename the raw profile file to vmlinux.profraw

Future PGO features may create other files in /sys/kernel/debug/pgo. So
rename the kernel's raw profile data file to "vmlinux.profraw" to make
which part of the kernel the file is for more explicit.

Note that future files in /sys/kernel/debug/pgo should follow a similar
naming convention.

Signed-off-by: Bill Wendling <morbo@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210531202044.426578-1-morbo@google.com

Documentation/dev-tools/pgo.rst

@@ -76,7 +76,7 @@ The PGO kernel support creates the following files in debugfs:
 ``/sys/kernel/debug/pgo/reset``
 	Global reset file: resets all coverage data to zero when written to.
 
-``/sys/kernel/debug/profraw``
+``/sys/kernel/debug/pgo/vmlinux.profraw``
 	The raw PGO data that must be processed with ``llvm_profdata``.
 
 
@@ -108,7 +108,7 @@ using the result to optimize the kernel:
 
    .. code-block:: sh
 
-      $ cp -a /sys/kernel/debug/pgo/profraw /tmp/vmlinux.profraw
+      $ cp -a /sys/kernel/debug/pgo/vmlinux.profraw /tmp/vmlinux.profraw
 
 5) (Optional) Download the raw profile data to the HOST machine.
 
@@ -120,7 +120,7 @@ using the result to optimize the kernel:
 
    Note that multiple raw profile data files can be merged during this step.
 
-7) Rebuild the kernel using the profile data (PGO disabled)
+7) Rebuild the kernel using the processed profile data (PGO disabled)
 
    .. code-block:: sh
 

kernel/pgo/Kconfig

@@ -17,10 +17,11 @@ config PGO_CLANG
 
 	  Run a representative workload for your application on a kernel
 	  compiled with this option and download the raw profile file from
-	  /sys/kernel/debug/pgo/profraw. This file needs to be processed with
-	  llvm-profdata. It may be merged with other collected raw profiles.
+	  /sys/kernel/debug/pgo/vmlinux.profraw. This file needs to be
+	  processed with llvm-profdata. It may be merged with other collected
+	  raw profiles.
 
-	  Copy the resulting profile file into vmlinux.profdata, and enable
+	  Copy the processed profile file into vmlinux.profdata, and enable
 	  KCFLAGS=-fprofile-use=vmlinux.profdata to produce an optimized
 	  kernel.
 

kernel/pgo/fs.c

@@ -365,7 +365,7 @@ static int __init pgo_init(void)
 	if (!directory)
 		goto err_remove;
 
-	if (!debugfs_create_file("profraw", 0600, directory, NULL,
+	if (!debugfs_create_file("vmlinux.profraw", 0600, directory, NULL,
 				 &prf_fops))
 		goto err_remove;