[PATCH 4.19 04/34] x86/cpufeature: Fix various quality problems in the header

Greg Kroah-Hartman
2022-11-21T12:45:21Z

From: Ingo Molnar <mingo@kernel.org>

Thomas noticed that the new arch/x86/include/asm/cpu_device_id.h header is
a train-wreck that didn't incorporate review feedback like not using __u8
in kernel-only headers.

While at it also fix all the *other* problems this header has:

- Use canonical names for the header guards. It's inexplicable why a non-standard
guard was used.

- Don't define the header guard to 1. Plus annotate the closing #endif as done
absolutely every other header. Again, an inexplicable source of noise.

- Move the kernel API calls provided by this header next to each other, there's
absolutely no reason to have them spread apart in the header.

- Align the INTEL_CPU_DESC() macro initializations vertically, this is easier to
read and it's also the canonical style.

- Actually name the macro arguments properly: instead of 'mod, step, rev',
spell out 'model, stepping, revision' - it's not like we have a lack of
characters in this header.

- Actually make arguments macro-safe - again it's inexplicable why it wasn't
done properly to begin with.

Quite amazing how many problems a 41 lines header can contain.

This kind of code quality is unacceptable, and it slipped through the
review net of 2 developers and 2 maintainers, including myself, until
Thomas noticed it. :-/

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _CPU_DEVICE_ID
-#define _CPU_DEVICE_ID 1
+#ifndef _ASM_X86_CPU_DEVICE_ID
+#define _ASM_X86_CPU_DEVICE_ID

/*
* Declare drivers belonging to specific x86 CPUs
@@ -9,8 +9,6 @@

#include <linux/mod_devicetable.h>

-extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
-
/*
* Match specific microcode revisions.
*
@@ -22,21 +20,22 @@ extern const struct x86_cpu_id *x86_matc
*/

struct x86_cpu_desc {
- __u8 x86_family;
- __u8 x86_vendor;
- __u8 x86_model;
- __u8 x86_stepping;
- __u32 x86_microcode_rev;
+ u8 x86_family;
+ u8 x86_vendor;
+ u8 x86_model;
+ u8 x86_stepping;
+ u32 x86_microcode_rev;
};

-#define INTEL_CPU_DESC(mod, step, rev) { \
- .x86_family = 6, \
- .x86_vendor = X86_VENDOR_INTEL, \
- .x86_model = mod, \
- .x86_stepping = step, \
- .x86_microcode_rev = rev, \
+#define INTEL_CPU_DESC(model, stepping, revision) { \
+ .x86_family = 6, \
+ .x86_vendor = X86_VENDOR_INTEL, \
+ .x86_model = (model), \
+ .x86_stepping = (stepping), \
+ .x86_microcode_rev = (revision), \
}

+extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
extern bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table);

-#endif
+#endif /* _ASM_X86_CPU_DEVICE_ID */