When we build this driver with on x86-32, gcc produces a false-positive warning:
drivers/clk/renesas/clk-sh73a0.c: In function 'sh73a0_cpg_clocks_init': drivers/clk/renesas/clk-sh73a0.c:155:10: error: 'parent_name' may be used uninitialized in this function [-Werror=maybe-uninitialized] return clk_register_fixed_factor(NULL, name, parent_name, 0,
We can work around that warning by adding a fake initialization, I tried and failed to come up with any better workaround. This is currently one of few remaining warnings for a 4.14.y randconfig build, so it would be good to also have it backported at least to that version. Older versions have more randconfig warnings, so we might not care.
I had not noticed this earlier, because one patch in my randconfig test tree removes the '-ffreestanding' option on x86-32, and that avoids the warning. The -ffreestanding flag was originally global but moved into arch/i386 by Andi Kleen in commit 6edfba1b33c7 ("[PATCH] x86_64: Don't define string functions to builtin") as a 'temporary workaround'.
Like many temporary hacks, this turned out to be rather long-lived, from all I can tell we still need a simple fix to asm/string_32.h before it can be removed, but I'm not sure about how to best do that.
Cc: stable@vger.kernel.org Cc: Andi Kleen ak@linux.intel.com Signed-off-by: Arnd Bergmann arnd@arndb.de --- drivers/clk/renesas/clk-sh73a0.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/clk/renesas/clk-sh73a0.c b/drivers/clk/renesas/clk-sh73a0.c index eea38f6ea77e..3892346c4fcc 100644 --- a/drivers/clk/renesas/clk-sh73a0.c +++ b/drivers/clk/renesas/clk-sh73a0.c @@ -46,7 +46,7 @@ struct div4_clk { unsigned int shift; };
-static struct div4_clk div4_clks[] = { +static const struct div4_clk div4_clks[] = { { "zg", "pll0", CPG_FRQCRA, 16 }, { "m3", "pll1", CPG_FRQCRA, 12 }, { "b", "pll1", CPG_FRQCRA, 8 }, @@ -79,7 +79,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, { const struct clk_div_table *table = NULL; unsigned int shift, reg, width; - const char *parent_name; + const char *parent_name = NULL; unsigned int mult = 1; unsigned int div = 1;
@@ -135,7 +135,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, shift = 24; width = 5; } else { - struct div4_clk *c; + const struct div4_clk *c;
for (c = div4_clks; c->name; c++) { if (!strcmp(name, c->name)) {
Hi Arnd,
On Fri, Feb 16, 2018 at 4:27 PM, Arnd Bergmann arnd@arndb.de wrote:
When we build this driver with on x86-32, gcc produces a false-positive warning:
drivers/clk/renesas/clk-sh73a0.c: In function 'sh73a0_cpg_clocks_init': drivers/clk/renesas/clk-sh73a0.c:155:10: error: 'parent_name' may be used uninitialized in this function [-Werror=maybe-uninitialized] return clk_register_fixed_factor(NULL, name, parent_name, 0,
We can work around that warning by adding a fake initialization, I tried and failed to come up with any better workaround. This is currently one of few remaining warnings for a 4.14.y randconfig build, so it would be good to also have it backported at least to that version. Older versions have more randconfig warnings, so we might not care.
I had not noticed this earlier, because one patch in my randconfig test tree removes the '-ffreestanding' option on x86-32, and that avoids the warning. The -ffreestanding flag was originally global but moved into arch/i386 by Andi Kleen in commit 6edfba1b33c7 ("[PATCH] x86_64: Don't define string functions to builtin") as a 'temporary workaround'.
Like many temporary hacks, this turned out to be rather long-lived, from all I can tell we still need a simple fix to asm/string_32.h before it can be removed, but I'm not sure about how to best do that.
Cc: stable@vger.kernel.org Cc: Andi Kleen ak@linux.intel.com Signed-off-by: Arnd Bergmann arnd@arndb.de
Thanks, this is a known false positive.
Acked-by: Geert Uytterhoeven geert+renesas@glider.be
drivers/clk/renesas/clk-sh73a0.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/clk/renesas/clk-sh73a0.c b/drivers/clk/renesas/clk-sh73a0.c index eea38f6ea77e..3892346c4fcc 100644 --- a/drivers/clk/renesas/clk-sh73a0.c +++ b/drivers/clk/renesas/clk-sh73a0.c @@ -46,7 +46,7 @@ struct div4_clk { unsigned int shift; };
-static struct div4_clk div4_clks[] = { +static const struct div4_clk div4_clks[] = {
This change is not part of the fix...
{ "zg", "pll0", CPG_FRQCRA, 16 }, { "m3", "pll1", CPG_FRQCRA, 12 }, { "b", "pll1", CPG_FRQCRA, 8 },@@ -79,7 +79,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, { const struct clk_div_table *table = NULL; unsigned int shift, reg, width;
const char *parent_name;
const char *parent_name = NULL; unsigned int mult = 1; unsigned int div = 1;@@ -135,7 +135,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, shift = 24; width = 5; } else {
struct div4_clk *c;
const struct div4_clk *c;
... and neither is this one.
for (c = div4_clks; c->name; c++) { if (!strcmp(name, c->name)) {
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Quoting Arnd Bergmann (2018-02-16 07:27:47)
When we build this driver with on x86-32, gcc produces a false-positive warning:
drivers/clk/renesas/clk-sh73a0.c: In function 'sh73a0_cpg_clocks_init': drivers/clk/renesas/clk-sh73a0.c:155:10: error: 'parent_name' may be used uninitialized in this function [-Werror=maybe-uninitialized] return clk_register_fixed_factor(NULL, name, parent_name, 0,
We can work around that warning by adding a fake initialization, I tried and failed to come up with any better workaround. This is currently one of few remaining warnings for a 4.14.y randconfig build, so it would be good to also have it backported at least to that version. Older versions have more randconfig warnings, so we might not care.
I had not noticed this earlier, because one patch in my randconfig test tree removes the '-ffreestanding' option on x86-32, and that avoids the warning. The -ffreestanding flag was originally global but moved into arch/i386 by Andi Kleen in commit 6edfba1b33c7 ("[PATCH] x86_64: Don't define string functions to builtin") as a 'temporary workaround'.
Like many temporary hacks, this turned out to be rather long-lived, from all I can tell we still need a simple fix to asm/string_32.h before it can be removed, but I'm not sure about how to best do that.
Cc: stable@vger.kernel.org Cc: Andi Kleen ak@linux.intel.com Signed-off-by: Arnd Bergmann arnd@arndb.de
Applied to clk-next
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