ARC minor fixes

Some fixlets for ARC.

Vineet Gupta (2):
ARC: Fix -Wmissing-prototypes warnings
ARC: mm: fix new code about cache aliasing

 arch/arc/Kconfig                 | 1 -
 arch/arc/include/asm/cachetype.h | 9 ---------
 arch/arc/include/asm/ptrace.h    | 2 +-
 arch/arc/kernel/kprobes.c        | 7 ++++---
 4 files changed, 5 insertions(+), 14 deletions(-)
 delete mode 100644 arch/arc/include/asm/cachetype.h

2.34.1

| ../arch/arc/kernel/kprobes.c:193:15: warning: no previous prototype for 'arc_kprobe_handler' [-Wmissing-prototypes]
|  193 | int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
|
|../arch/arc/kernel/ptrace.c:342:16: warning: no previous prototype for 'syscall_trace_enter' [-Wmissing-prototypes]
|  342 | asmlinkage int syscall_trace_enter(struct pt_regs *regs)

---
 arch/arc/include/asm/ptrace.h | 2 +-
 arch/arc/kernel/kprobes.c     | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

index 00b9318e551e..cf79df0b2570 100644
@@ -169,7 +169,7 @@ static inline unsigned long regs_get_register(struct pt_regs *regs,
 	return *(unsigned long *)((unsigned long)regs + offset);
 }
 
-extern int syscall_trace_entry(struct pt_regs *);
+extern int syscall_trace_enter(struct pt_regs *);
 extern void syscall_trace_exit(struct pt_regs *);
 
 #endif /* !__ASSEMBLY__ */

index e71d64119d71..f8e2960832d9 100644
@@ -190,7 +190,8 @@ static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs)
 	}
 }
 
-int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
+static int
+__kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
 {
 	struct kprobe *p;
 	struct kprobe_ctlblk *kcb;

@@ -241,8 +242,8 @@ int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
 	return 0;
 }
 
-static int __kprobes arc_post_kprobe_handler(unsigned long addr,
-					 struct pt_regs *regs)
+static int
+__kprobes arc_post_kprobe_handler(unsigned long addr, struct pt_regs *regs)
 {
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

2.34.1

Manual/partial revert of 8690bbcf3b70 ("Introduce cpu_dcache_is_aliasing() across all architectures")

Current generation of ARCv2/ARCv3 based HSxx cores are only PIPT (to software at least).

Legacy ARC700 cpus could be VIPT aliasing (based on cache geometry and PAGE_SIZE) however recently that support was ripped out so VIPT aliasing cache is not relevant to ARC anymore.

P.S. : This has been discussed a few times on lists [1] P.S.2: Please CC the arch maintainers and/or mailing list before adding
such interfaces.

[1] http://lists.infradead.org/pipermail/linux-snps-arc/2023-February/006899.html

---
 arch/arc/Kconfig                 | 1 -
 arch/arc/include/asm/cachetype.h | 9 ---------
 2 files changed, 10 deletions(-)
 delete mode 100644 arch/arc/include/asm/cachetype.h

index 99d2845f3feb..4092bec198be 100644
@@ -6,7 +6,6 @@
 config ARC
 	def_bool y
 	select ARC_TIMERS
-	select ARCH_HAS_CPU_CACHE_ALIASING
 	select ARCH_HAS_CACHE_LINE_SIZE
 	select ARCH_HAS_DEBUG_VM_PGTABLE
 	select ARCH_HAS_DMA_PREP_COHERENT

deleted file mode 100644
index 05fc7ed59712..000000000000
@@ -1,9 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __ASM_ARC_CACHETYPE_H
-#define __ASM_ARC_CACHETYPE_H
-
-#include <linux/types.h>
-
-#define cpu_dcache_is_aliasing()	true
-
-#endif

2.34.1

Because 8690bbcf3b70 was introducing a tree-wide change affecting all architectures, I CC'd [email protected]. I expected all architecture maintainers to follow that list, which is relatively low volume.

I'm sorry that you learn about this after the fact as a result. My intent was to use the list rather than CC about 50 additional people/mailing lists.

Of course, if VIPT aliasing is removed from ARC, removing the config ARCH_HAS_CPU_CACHE_ALIASING and using the generic cpu_dcache_is_aliasing() is the way to go. Feel free to add my:

Thanks,

Mathieu

Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com

Ideally yeah arch maintainers should be lurking there.

Please don't be, no harm done, the fix was easy ;-)

That is true but I don't think maintainers mind that in general. I still posit that any new interfaces to arch code should be explicitly run by them.

Thx,
-Vineet