m68k: Don't unregister boot console needlessly

When MACH_IS_MVME147, the boot console calls mvme147_scc_write() to
generate console output. That will continue to work even after
debug_cons_nputs() becomes unavailable so there's no need to
unregister the boot console.

Take the opportunity to remove a repeated MACH_IS_* test. Use the
actual .write method (instead of a wrapper) and test that pointer
instead. This means adding an unused parameter to debug_cons_nputs() for
consistency with the struct console API.

early_printk.c is only built when CONFIG_EARLY_PRINTK=y. As of late,
head.S is only built when CONFIG_MMU_MOTOROLA=y. So let the former symbol
depend on the latter, to obviate some ifdef conditionals.

Cc: Daniel Palmer <daniel@0x0f.com>
Fixes: 077b33b9e283 ("m68k: mvme147: Reinstate early console")
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/d1d4328e5aa9a87bd8352529ce62b767731c0530.1743467205.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --git a/arch/m68k/Kconfig.debug b/arch/m68k/Kconfig.debug
index 30638a6e8edcb35e72c283911321cd3e304cf40c..d036f903864c268c476f0544126dfcdde271151d 100644 (file)
--- a/arch/m68k/Kconfig.debug
+++ b/arch/m68k/Kconfig.debug
@@ -10,7 +10,7 @@ config BOOTPARAM_STRING
 
 config EARLY_PRINTK
        bool "Early printk"
-       depends on !(SUN3 || M68000 || COLDFIRE)
+       depends on MMU_MOTOROLA
        help
          Write kernel log output directly to a serial port.
          Where implemented, output goes to the framebuffer as well.

diff --git a/arch/m68k/kernel/early_printk.c b/arch/m68k/kernel/early_printk.c
index f11ef9f1f56fcfcc2217a6eb98f8a05a17f77179..521cbb8a150c99dcbd447efa9732d9f296f35503 100644 (file)
--- a/arch/m68k/kernel/early_printk.c
+++ b/arch/m68k/kernel/early_printk.c
@@ -16,25 +16,10 @@
 #include "../mvme147/mvme147.h"
 #include "../mvme16x/mvme16x.h"
 
-asmlinkage void __init debug_cons_nputs(const char *s, unsigned n);
-
-static void __ref debug_cons_write(struct console *c,
-                                  const char *s, unsigned n)
-{
-#if !(defined(CONFIG_SUN3) || defined(CONFIG_M68000) || \
-      defined(CONFIG_COLDFIRE))
-       if (MACH_IS_MVME147)
-               mvme147_scc_write(c, s, n);
-       else if (MACH_IS_MVME16x)
-               mvme16x_cons_write(c, s, n);
-       else
-               debug_cons_nputs(s, n);
-#endif
-}
+asmlinkage void __init debug_cons_nputs(struct console *c, const char *s, unsigned int n);
 
 static struct console early_console_instance = {
        .name  = "debug",
-       .write = debug_cons_write,
        .flags = CON_PRINTBUFFER | CON_BOOT,
        .index = -1
 };
@@ -44,6 +29,12 @@ static int __init setup_early_printk(char *buf)
        if (early_console || buf)
                return 0;
 
+       if (MACH_IS_MVME147)
+               early_console_instance.write = mvme147_scc_write;
+       else if (MACH_IS_MVME16x)
+               early_console_instance.write = mvme16x_cons_write;
+       else
+               early_console_instance.write = debug_cons_nputs;
        early_console = &early_console_instance;
        register_console(early_console);
 
@@ -51,20 +42,15 @@ static int __init setup_early_printk(char *buf)
 }
 early_param("earlyprintk", setup_early_printk);
 
-/*
- * debug_cons_nputs() defined in arch/m68k/kernel/head.S cannot be called
- * after init sections are discarded (for platforms that use it).
- */
-#if !(defined(CONFIG_SUN3) || defined(CONFIG_M68000) || \
-      defined(CONFIG_COLDFIRE))
-
 static int __init unregister_early_console(void)
 {
-       if (!early_console || MACH_IS_MVME16x)
-               return 0;
+       /*
+        * debug_cons_nputs() defined in arch/m68k/kernel/head.S cannot be
+        * called after init sections are discarded (for platforms that use it).
+        */
+       if (early_console && early_console->write == debug_cons_nputs)
+               return unregister_console(early_console);
 
-       return unregister_console(early_console);
+       return 0;
 }
 late_initcall(unregister_early_console);
-
-#endif

diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S
index 6465333d5f7c05a3fddfba454c6a33886c8bf195..2e4ef0358887c61495772a5afe407f87e8b66e96 100644 (file)
--- a/arch/m68k/kernel/head.S
+++ b/arch/m68k/kernel/head.S
@@ -3263,8 +3263,8 @@ func_return       putn
  *     turns around and calls the internal routines.  This routine
  *     is used by the boot console.
  *
- *     The calling parameters are:
- *             void debug_cons_nputs(const char *str, unsigned length)
+ *     The function signature is -
+ *             void debug_cons_nputs(struct console *c, const char *s, unsigned int n)
  *
  *     This routine does NOT understand variable arguments only
  *     simple strings!
@@ -3273,8 +3273,8 @@ ENTRY(debug_cons_nputs)
        moveml  %d0/%d1/%a0,%sp@-
        movew   %sr,%sp@-
        ori     #0x0700,%sr
-       movel   %sp@(18),%a0            /* fetch parameter */
-       movel   %sp@(22),%d1            /* fetch parameter */
+       movel   %sp@(22),%a0            /* char *s */
+       movel   %sp@(26),%d1            /* unsigned int n */
        jra     2f
 1:
 #ifdef CONSOLE_DEBUG