* [PATCH] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool
@ 2019-05-15 12:09 Mathieu Malaterre
2019-05-15 13:14 ` Christoph Hellwig
2019-05-15 13:51 ` [PATCH v2] " Mathieu Malaterre
0 siblings, 2 replies; 4+ messages in thread
From: Mathieu Malaterre @ 2019-05-15 12:09 UTC (permalink / raw)
To: Michael Ellerman
Cc: Mathieu Malaterre, Michael Neuling, Benjamin Herrenschmidt,
Paul Mackerras, linuxppc-dev, linux-kernel
In commit c1fe190c0672 ("powerpc: Add force enable of DAWR on P9
option") the following piece of code was added:
smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
Since GCC 8 this trigger the following warning about incompatible
function types:
arch/powerpc/kernel/hw_breakpoint.c:408:21: error: cast between incompatible function types from 'int (*)(struct arch_hw_breakpoint *)' to 'void (*)(void *)' [-Werror=cast-function-type]
Cast the function to an intermediate (void*) to make the compiler loose
knowledge about actual type.
Fixes: c1fe190c0672 ("powerpc: Add force enable of DAWR on P9 option")
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
---
arch/powerpc/kernel/hw_breakpoint.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index f70fb89dbf60..baeb4c58de3b 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -405,7 +405,8 @@ static ssize_t dawr_write_file_bool(struct file *file,
/* If we are clearing, make sure all CPUs have the DAWR cleared */
if (!dawr_force_enable)
- smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
+ smp_call_function((smp_call_func_t)(void *)set_dawr,
+ &null_brk, 0);
return rc;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool
2019-05-15 12:09 [PATCH] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool Mathieu Malaterre
@ 2019-05-15 13:14 ` Christoph Hellwig
2019-05-15 13:37 ` Mathieu Malaterre
2019-05-15 13:51 ` [PATCH v2] " Mathieu Malaterre
1 sibling, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2019-05-15 13:14 UTC (permalink / raw)
To: Mathieu Malaterre
Cc: Michael Ellerman, Michael Neuling, linux-kernel, Paul Mackerras,
linuxppc-dev
On Wed, May 15, 2019 at 02:09:42PM +0200, Mathieu Malaterre wrote:
> In commit c1fe190c0672 ("powerpc: Add force enable of DAWR on P9
> option") the following piece of code was added:
>
> smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
>
> Since GCC 8 this trigger the following warning about incompatible
> function types:
And the warning is there for a reason, and should not be hidden
behind a cast. This should instead be fixed by something like this:
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index da307dd93ee3..a26b67a1be83 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -384,6 +384,12 @@ void hw_breakpoint_pmu_read(struct perf_event *bp)
bool dawr_force_enable;
EXPORT_SYMBOL_GPL(dawr_force_enable);
+
+static void set_dawr_cb(void *info)
+{
+ set_dawr(info);
+}
+
static ssize_t dawr_write_file_bool(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
@@ -403,7 +409,7 @@ static ssize_t dawr_write_file_bool(struct file *file,
/* If we are clearing, make sure all CPUs have the DAWR cleared */
if (!dawr_force_enable)
- smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
+ smp_call_function(set_dawr_cb, &null_brk, 0);
return rc;
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool
2019-05-15 13:14 ` Christoph Hellwig
@ 2019-05-15 13:37 ` Mathieu Malaterre
0 siblings, 0 replies; 4+ messages in thread
From: Mathieu Malaterre @ 2019-05-15 13:37 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Michael Ellerman, Michael Neuling, LKML, Paul Mackerras,
linuxppc-dev
Hi Christoph,
On Wed, May 15, 2019 at 3:14 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Wed, May 15, 2019 at 02:09:42PM +0200, Mathieu Malaterre wrote:
> > In commit c1fe190c0672 ("powerpc: Add force enable of DAWR on P9
> > option") the following piece of code was added:
> >
> > smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
> >
> > Since GCC 8 this trigger the following warning about incompatible
> > function types:
>
> And the warning is there for a reason, and should not be hidden
> behind a cast. This should instead be fixed by something like this:
<meme: I have no idea what I am doing>
OK, thanks for the quick feedback, will send a v2 asap.
> diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
> index da307dd93ee3..a26b67a1be83 100644
> --- a/arch/powerpc/kernel/hw_breakpoint.c
> +++ b/arch/powerpc/kernel/hw_breakpoint.c
> @@ -384,6 +384,12 @@ void hw_breakpoint_pmu_read(struct perf_event *bp)
> bool dawr_force_enable;
> EXPORT_SYMBOL_GPL(dawr_force_enable);
>
> +
> +static void set_dawr_cb(void *info)
> +{
> + set_dawr(info);
> +}
> +
> static ssize_t dawr_write_file_bool(struct file *file,
> const char __user *user_buf,
> size_t count, loff_t *ppos)
> @@ -403,7 +409,7 @@ static ssize_t dawr_write_file_bool(struct file *file,
>
> /* If we are clearing, make sure all CPUs have the DAWR cleared */
> if (!dawr_force_enable)
> - smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
> + smp_call_function(set_dawr_cb, &null_brk, 0);
>
> return rc;
> }
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool
2019-05-15 12:09 [PATCH] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool Mathieu Malaterre
2019-05-15 13:14 ` Christoph Hellwig
@ 2019-05-15 13:51 ` Mathieu Malaterre
1 sibling, 0 replies; 4+ messages in thread
From: Mathieu Malaterre @ 2019-05-15 13:51 UTC (permalink / raw)
To: Michael Ellerman
Cc: Mathieu Malaterre, Christoph Hellwig, Michael Neuling,
Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev,
linux-kernel
In commit c1fe190c0672 ("powerpc: Add force enable of DAWR on P9
option") the following piece of code was added:
smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
Since GCC 8 this triggers the following warning about incompatible
function types:
arch/powerpc/kernel/hw_breakpoint.c:408:21: error: cast between incompatible function types from 'int (*)(struct arch_hw_breakpoint *)' to 'void (*)(void *)' [-Werror=cast-function-type]
Since the warning is there for a reason, and should not be hidden behind
a cast, provide an intermediate callback function to avoid the warning.
Fixes: c1fe190c0672 ("powerpc: Add force enable of DAWR on P9 option")
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
---
v2: do not hide warning using a hack
arch/powerpc/kernel/hw_breakpoint.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index f70fb89dbf60..969092d84a2f 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -386,6 +386,11 @@ void hw_breakpoint_pmu_read(struct perf_event *bp)
bool dawr_force_enable;
EXPORT_SYMBOL_GPL(dawr_force_enable);
+static void set_dawr_cb(void *info)
+{
+ set_dawr(info);
+}
+
static ssize_t dawr_write_file_bool(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
@@ -405,7 +410,7 @@ static ssize_t dawr_write_file_bool(struct file *file,
/* If we are clearing, make sure all CPUs have the DAWR cleared */
if (!dawr_force_enable)
- smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
+ smp_call_function(set_dawr_cb, &null_brk, 0);
return rc;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2019-05-15 12:09 [PATCH] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool Mathieu Malaterre
2019-05-15 13:14 ` Christoph Hellwig
2019-05-15 13:37 ` Mathieu Malaterre
2019-05-15 13:51 ` [PATCH v2] " Mathieu Malaterre
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