Re: [PATCH v2] powerpc/prom_init: add __init markers to all functions

[Christophe Leroy]

Le 20/02/2019 à 06:53, Masahiro Yamada a écrit :
It is fragile to rely on the compiler's optimization to avoid the
section mismatch. Some functions may not be necessarily inlined
when the compiler's inlining heuristic changes.

Add __init markers consistently.

As for prom_getprop() and prom_getproplen(), they are marked as
'inline', so inlining is guaranteed because PowerPC never enables
CONFIG_OPTIMIZE_INLINING. However, it would be better to leave the
inlining decision to the compiler. I replaced 'inline' with __init.
I added __maybe_unused to prom_getproplen() because it is currently
relying on the side-effect of 'inline'; GCC does not report
-Wunused-function warnings for functions with 'inline' marker.

__maybe_unused is really a bad trick that should be avoided, as it hides 
unused functions.

Why is it a problem to keep prom_getproplen() as 'static inline' ? Most 
small helpers are defined that way. Usually they are in an included 
header file, but what's really the problem with having it here directly ?

Christophe


Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com>
---

Changes in v2:
   - Add __maybe_unsed to prom_getproplen()
   - Add __init to enter_prom() as well

  arch/powerpc/kernel/prom_init.c | 29 +++++++++++++++--------------
  1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index f33ff41..1bad0ac 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -138,9 +138,9 @@ extern void __start(unsigned long r3, unsigned long r4, 
unsigned long r5,
                    unsigned long r9);
  
  #ifdef CONFIG_PPC64
-extern int enter_prom(struct prom_args *args, unsigned long entry);
+extern int __init enter_prom(struct prom_args *args, unsigned long entry);
  #else
-static inline int enter_prom(struct prom_args *args, unsigned long entry)
+static int __init enter_prom(struct prom_args *args, unsigned long entry)
  {
        return ((int (*)(struct prom_args *))entry)(args);
  }
@@ -501,19 +501,20 @@ static int __init prom_next_node(phandle *nodep)
        }
  }
  
-static inline int prom_getprop(phandle node, const char *pname,
+static int __init prom_getprop(phandle node, const char *pname,
                               void *value, size_t valuelen)
  {
        return call_prom("getprop", 4, 1, node, ADDR(pname),
                         (u32)(unsigned long) value, (u32) valuelen);
  }
  
-static inline int prom_getproplen(phandle node, const char *pname)
+static int __init __maybe_unused prom_getproplen(phandle node,
+                                                const char *pname)
  {
        return call_prom("getproplen", 2, 1, node, ADDR(pname));
  }
  
-static void add_string(char **str, const char *q)
+static void __init add_string(char **str, const char *q)
  {
        char *p = *str;
  
@@ -523,7 +524,7 @@ static void add_string(char **str, const char *q)
        *str = p;
  }
  
-static char *tohex(unsigned int x)
+static char __init *tohex(unsigned int x)
  {
        static const char digits[] __initconst = "0123456789abcdef";
        static char result[9] __prombss;
@@ -570,7 +571,7 @@ static int __init prom_setprop(phandle node, const char 
*nodename,
  #define islower(c)    ('a' <= (c) && (c) <= 'z')
  #define toupper(c)    (islower(c) ? ((c) - 'a' + 'A') : (c))
  
-static unsigned long prom_strtoul(const char *cp, const char **endp)
+static unsigned long __init prom_strtoul(const char *cp, const char **endp)
  {
        unsigned long result = 0, base = 10, value;
  
@@ -595,7 +596,7 @@ static unsigned long prom_strtoul(const char *cp, const char **endp)
        return result;
  }
  
-static unsigned long prom_memparse(const char *ptr, const char **retptr)
+static unsigned long __init prom_memparse(const char *ptr, const char **retptr)
  {
        unsigned long ret = prom_strtoul(ptr, retptr);
        int shift = 0;
@@ -2924,7 +2925,7 @@ static void __init fixup_device_tree_pasemi(void)
        prom_setprop(iob, name, "device_type", "isa", sizeof("isa"));
  }
  #else /* !CONFIG_PPC_PASEMI_NEMO */
-static inline void fixup_device_tree_pasemi(void) { }
+static void __init fixup_device_tree_pasemi(void) { }
  #endif
  
  static void __init fixup_device_tree(void)
@@ -2986,15 +2987,15 @@ static void __init prom_check_initrd(unsigned long r3, 
unsigned long r4)
  
  #ifdef CONFIG_PPC64
  #ifdef CONFIG_RELOCATABLE
-static void reloc_toc(void)
+static void __init reloc_toc(void)
  {
  }
  
-static void unreloc_toc(void)
+static void __init unreloc_toc(void)
  {
  }
  #else
-static void __reloc_toc(unsigned long offset, unsigned long nr_entries)
+static void __init __reloc_toc(unsigned long offset, unsigned long nr_entries)
  {
        unsigned long i;
        unsigned long *toc_entry;
@@ -3008,7 +3009,7 @@ static void __reloc_toc(unsigned long offset, unsigned 
long nr_entries)
        }
  }
  
-static void reloc_toc(void)
+static void __init reloc_toc(void)
  {
        unsigned long offset = reloc_offset();
        unsigned long nr_entries =
@@ -3019,7 +3020,7 @@ static void reloc_toc(void)
        mb();
  }
  
-static void unreloc_toc(void)
+static void __init unreloc_toc(void)
  {
        unsigned long offset = reloc_offset();
        unsigned long nr_entries =