arm: ptdump: rename CONFIG_DEBUG_WX to CONFIG_ARM_DEBUG_WX

Patch series "mm: ptdump: Refactor CONFIG_DEBUG_WX and check_wx_pages
debugfs attribute", v2.

This series refactors CONFIG_DEBUG_WX for the 5 architectures implementing
CONFIG_GENERIC_PTDUMP

First rename stuff in ARM which uses similar names while not implementing
CONFIG_GENERIC_PTDUMP.

Then define a generic version of debug_checkwx() that calls
ptdump_check_wx() when CONFIG_DEBUG_WX is set.  Call it immediately after
calling mark_rodata_ro() instead of calling it at the end of every
mark_rodata_ro().

Then implement a debugfs attribute that can be used to trigger a W^X test
at anytime and regardless of CONFIG_DEBUG_WX


This patch (of 5):

CONFIG_DEBUG_WX is a core option defined in mm/Kconfig.debug

To avoid any future conflict, rename ARM version into CONFIG_ARM_DEBUG_WX.

Link: https://lore.kernel.org/lkml/20200422152656.GF676@willie-the-truck/T/#m802eaf33efd6f8d575939d157301b35ac0d4a64f
Link: https://github.com/KSPP/linux/issues/35
Link: https://lkml.kernel.org/r/cover.1706610398.git.christophe.leroy@csgroup.eu
Link: https://lkml.kernel.org/r/fa297aa90caeb61eee2b70c6c5897a2ab58a9562.1706610398.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Phong Tran <tranmanphong@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Price <steven.price@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm/Kconfig.debug

@@ -17,7 +17,7 @@ config ARM_PTDUMP_DEBUGFS
 	  kernel.
 	  If in doubt, say "N"
 
-config DEBUG_WX
+config ARM_DEBUG_WX
 	bool "Warn on W+X mappings at boot"
 	depends on MMU
 	select ARM_PTDUMP_CORE

arch/arm/configs/aspeed_g4_defconfig

@@ -252,7 +252,7 @@ CONFIG_DEBUG_INFO_REDUCED=y
 CONFIG_GDB_SCRIPTS=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
-CONFIG_DEBUG_WX=y
+CONFIG_ARM_DEBUG_WX=y
 CONFIG_SCHED_STACK_END_CHECK=y
 CONFIG_PANIC_ON_OOPS=y
 CONFIG_PANIC_TIMEOUT=-1

arch/arm/configs/aspeed_g5_defconfig

@@ -302,7 +302,7 @@ CONFIG_DEBUG_INFO_REDUCED=y
 CONFIG_GDB_SCRIPTS=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
-CONFIG_DEBUG_WX=y
+CONFIG_ARM_DEBUG_WX=y
 CONFIG_SCHED_STACK_END_CHECK=y
 CONFIG_PANIC_ON_OOPS=y
 CONFIG_PANIC_TIMEOUT=-1

arch/arm/include/asm/ptdump.h

@@ -32,10 +32,10 @@ void ptdump_check_wx(void);
 
 #endif /* CONFIG_ARM_PTDUMP_CORE */
 
-#ifdef CONFIG_DEBUG_WX
-#define debug_checkwx() ptdump_check_wx()
+#ifdef CONFIG_ARM_DEBUG_WX
+#define arm_debug_checkwx() ptdump_check_wx()
 #else
-#define debug_checkwx() do { } while (0)
+#define arm_debug_checkwx() do { } while (0)
 #endif
 
 #endif /* __ASM_PTDUMP_H */

arch/arm/mm/init.c

@@ -458,7 +458,7 @@ static int __mark_rodata_ro(void *unused)
 void mark_rodata_ro(void)
 {
 	stop_machine(__mark_rodata_ro, NULL, NULL);
-	debug_checkwx();
+	arm_debug_checkwx();
 }
 
 #else