entry: Rename arch_check_user_regs() to arch_enter_from_user_mode()

arch_check_user_regs() is used at the moment to verify that struct pt_regs
contains valid values when entering the kernel from userspace. s390 needs
a place in the generic entry code to modify a cpu data structure when
switching from userspace to kernel mode. As arch_check_user_regs() is
exactly this, rename it to arch_enter_from_user_mode().

When entering the kernel from userspace, arch_check_user_regs() is
used to verify that struct pt_regs contains valid values. Note that
the NMI codepath doesn't call this function. s390 needs a place in the
generic entry code to modify a cpu data structure when switching from
userspace to kernel mode. As arch_check_user_regs() is exactly this,
rename it to arch_enter_from_user_mode().

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220504062351.2954280-2-tmricht@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Author: svens-s390

arch/s390/include/asm/entry-common.h

@@ -15,12 +15,12 @@
 void do_per_trap(struct pt_regs *regs);
 
 #ifdef CONFIG_DEBUG_ENTRY
-static __always_inline void arch_check_user_regs(struct pt_regs *regs)
+static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs)
 {
 	debug_user_asce(0);
 }
 
-#define arch_check_user_regs arch_check_user_regs
+#define arch_enter_from_user_mode arch_enter_from_user_mode
 #endif /* CONFIG_DEBUG_ENTRY */
 
 static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs,

arch/x86/include/asm/entry-common.h

@@ -10,7 +10,7 @@
 #include <asm/fpu/api.h>
 
 /* Check that the stack and regs on entry from user mode are sane. */
-static __always_inline void arch_check_user_regs(struct pt_regs *regs)
+static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs)
 {
 	if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) {
 		/*
@@ -42,7 +42,7 @@ static __always_inline void arch_check_user_regs(struct pt_regs *regs)
 		WARN_ON_ONCE(regs != task_pt_regs(current));
 	}
 }
-#define arch_check_user_regs arch_check_user_regs
+#define arch_enter_from_user_mode arch_enter_from_user_mode
 
 static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
 						  unsigned long ti_work)

include/linux/entry-common.h

@@ -63,7 +63,7 @@
 	 ARCH_EXIT_TO_USER_MODE_WORK)
 
 /**
- * arch_check_user_regs - Architecture specific sanity check for user mode regs
+ * arch_enter_from_user_mode - Architecture specific sanity check for user mode regs
  * @regs:	Pointer to currents pt_regs
  *
  * Defaults to an empty implementation. Can be replaced by architecture
@@ -73,10 +73,10 @@
  * section. Use __always_inline so the compiler cannot push it out of line
  * and make it instrumentable.
  */
-static __always_inline void arch_check_user_regs(struct pt_regs *regs);
+static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs);
 
-#ifndef arch_check_user_regs
-static __always_inline void arch_check_user_regs(struct pt_regs *regs) {}
+#ifndef arch_enter_from_user_mode
+static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) {}
 #endif
 
 /**

kernel/entry/common.c

@@ -17,7 +17,7 @@
 /* See comment for enter_from_user_mode() in entry-common.h */
 static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
 {
-	arch_check_user_regs(regs);
+	arch_enter_from_user_mode(regs);
 	lockdep_hardirqs_off(CALLER_ADDR0);
 
 	CT_WARN_ON(ct_state() != CONTEXT_USER);