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

From: Christophe Leroy
Date: Wed Feb 20 2019 - 01:54:07 EST




Le 20/02/2019 Ã 06:53, Masahiro Yamada a ÃcritÂ:
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.masahiro@xxxxxxxxxxxxx>
---

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 =