[tip: locking/core] locking/lockdep: Reduce LOCKDEP dependency list

[tip-bot2 for Randy Dunlap]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     b8e00abe7d9fe21dd13609e2e3a707e38902b105
Gitweb:        https://git.kernel.org/tip/b8e00abe7d9fe21dd13609e2e3a707e38902b105
Author:        Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
AuthorDate:    Mon, 24 May 2021 15:41:50 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 31 May 2021 10:14:54 +02:00

locking/lockdep: Reduce LOCKDEP dependency list

Some arches (um, sparc64, riscv, xtensa) cause a Kconfig warning for
LOCKDEP.
These arch-es select LOCKDEP_SUPPORT but they are not listed as one
of the arch-es that LOCKDEP depends on.

Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they
intend to have LOCKDEP support, replace the awkward list of
arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol.

But wait. LOCKDEP_SUPPORT is included in LOCK_DEBUGGING_SUPPORT,
which is already a dependency here, so LOCKDEP_SUPPORT is redundant
and not needed.
That leaves the FRAME_POINTER dependency, but it is part of an
expression like this:
	depends on (A && B) && (FRAME_POINTER || B')
where B' is a dependency of B so if B is true then B' is true
and the value of FRAME_POINTER does not matter.
Thus we can also delete the FRAME_POINTER dependency.

Fixes this kconfig warning: (for um, sparc64, riscv, xtensa)

WARNING: unmet direct dependencies detected for LOCKDEP
  Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86)
  Selected by [y]:
  - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y]
  - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y]
  - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y]

Fixes: 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Waiman Long <longman@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20210524224150.8009-1-rdunlap@xxxxxxxxxxxxx
---
 lib/Kconfig.debug | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 678c139..1e1bd6f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1372,7 +1372,6 @@ config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
 	select STACKTRACE
-	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
 	select KALLSYMS
 	select KALLSYMS_ALL