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Subject[PATCH v4] powerpc/setup_64: fix -Wempty-body warnings
Date
At the beginning of setup_64.c, it has,

#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

where DBG() could be compiled away, and generate warnings,

arch/powerpc/kernel/setup_64.c: In function 'initialize_cache_info':
arch/powerpc/kernel/setup_64.c:579:49: warning: suggest braces around
empty body in an 'if' statement [-Wempty-body]
DBG("Argh, can't find dcache properties !\n");
^
arch/powerpc/kernel/setup_64.c:582:49: warning: suggest braces around
empty body in an 'if' statement [-Wempty-body]
DBG("Argh, can't find icache properties !\n");

Fix it by using the suggestions from Michael:

"Neither of those sites should use DBG(), that's not really early boot
code, they should just use pr_warn().

And the other uses of DBG() in initialize_cache_info() should just be
removed.

In smp_release_cpus() the entry/exit DBG's should just be removed, and
the spinning_secondaries line should just be pr_debug().

That would just leave the two calls in early_setup(). If we taught
udbg_printf() to return early when udbg_putc is NULL, then we could just
call udbg_printf() unconditionally and get rid of the DBG macro
entirely."

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Qian Cai <cai@lca.pw>
---

v4: Use the suggestions from Michael and __func__ per checkpatch.
v3: Use no_printk() macro, and make sure that format and argument are always
verified by the compiler using a more generic form ##__VA_ARGS__ per Joe.
v2: Fix it by using a NOP while loop per Tyrel.

arch/powerpc/kernel/setup_64.c | 26 ++++++--------------------
arch/powerpc/kernel/udbg.c | 14 ++++++++------
2 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 44b4c432a273..d2af4c228970 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -68,12 +68,6 @@

#include "setup.h"

-#ifdef DEBUG
-#define DBG(fmt...) udbg_printf(fmt)
-#else
-#define DBG(fmt...)
-#endif
-
int spinning_secondaries;
u64 ppc64_pft_size;

@@ -305,7 +299,7 @@ void __init early_setup(unsigned long dt_ptr)
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();

- DBG(" -> early_setup(), dt_ptr: 0x%lx\n", dt_ptr);
+ udbg_printf(" -> %s(), dt_ptr: 0x%lx\n", __func__, dt_ptr);

/*
* Do early initialization using the flattened device
@@ -362,11 +356,11 @@ void __init early_setup(unsigned long dt_ptr)
*/
this_cpu_enable_ftrace();

- DBG(" <- early_setup()\n");
+ udbg_printf(" <- %s()\n", __func__);

#ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
/*
- * This needs to be done *last* (after the above DBG() even)
+ * This needs to be done *last* (after the above udbg_printf() even)
*
* Right after we return from this function, we turn on the MMU
* which means the real-mode access trick that btext does will
@@ -436,8 +430,6 @@ void smp_release_cpus(void)
if (!use_spinloop())
return;

- DBG(" -> smp_release_cpus()\n");
-
/* All secondary cpus are spinning on a common spinloop, release them
* all now so they can start to spin on their individual paca
* spinloops. For non SMP kernels, the secondary cpus never get out
@@ -456,9 +448,7 @@ void smp_release_cpus(void)
break;
udelay(1);
}
- DBG("spinning_secondaries = %d\n", spinning_secondaries);
-
- DBG(" <- smp_release_cpus()\n");
+ pr_debug("spinning_secondaries = %d\n", spinning_secondaries);
}
#endif /* CONFIG_SMP || CONFIG_KEXEC_CORE */

@@ -551,8 +541,6 @@ void __init initialize_cache_info(void)
struct device_node *cpu = NULL, *l2, *l3 = NULL;
u32 pvr;

- DBG(" -> initialize_cache_info()\n");
-
/*
* All shipping POWER8 machines have a firmware bug that
* puts incorrect information in the device-tree. This will
@@ -576,10 +564,10 @@ void __init initialize_cache_info(void)
*/
if (cpu) {
if (!parse_cache_info(cpu, false, &ppc64_caches.l1d))
- DBG("Argh, can't find dcache properties !\n");
+ pr_warn("Argh, can't find dcache properties !\n");

if (!parse_cache_info(cpu, true, &ppc64_caches.l1i))
- DBG("Argh, can't find icache properties !\n");
+ pr_warn("Argh, can't find icache properties !\n");

/*
* Try to find the L2 and L3 if any. Assume they are
@@ -604,8 +592,6 @@ void __init initialize_cache_info(void)

cur_cpu_spec->dcache_bsize = dcache_bsize;
cur_cpu_spec->icache_bsize = icache_bsize;
-
- DBG(" <- initialize_cache_info()\n");
}

/*
diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c
index a384e7c8b01c..01595e8cafe7 100644
--- a/arch/powerpc/kernel/udbg.c
+++ b/arch/powerpc/kernel/udbg.c
@@ -120,13 +120,15 @@ int udbg_write(const char *s, int n)
#define UDBG_BUFSIZE 256
void udbg_printf(const char *fmt, ...)
{
- char buf[UDBG_BUFSIZE];
- va_list args;
+ if (udbg_putc) {
+ char buf[UDBG_BUFSIZE];
+ va_list args;

- va_start(args, fmt);
- vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
- udbg_puts(buf);
- va_end(args);
+ va_start(args, fmt);
+ vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
+ udbg_puts(buf);
+ va_end(args);
+ }
}

void __init udbg_progress(char *s, unsigned short hex)
--
1.8.3.1
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