Subject: [PATCH AUTOSEL 5.2 105/171] powerpc: silence a -Wcast-function-type warning in dawr_write_file_bool

From: Sasha Levin <[email-masked]>
Date: Thu, 18 Jul 2019 23:55:36 -0400

From: Mathieu Malaterre <[email-masked]>

[ Upstream commit 548c54acba5bd1388d50727a9a126a42d0cd4ad0 ]

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 <[email-masked]>
Signed-off-by: Mathieu Malaterre <[email-masked]>
Signed-off-by: Michael Neuling <[email-masked]>
Signed-off-by: Michael Ellerman <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 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 a293a53b4365..50262597c222 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -370,6 +370,11 @@ 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)
@@ -389,7 +394,7 @@ 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