[Devel] [PATCH vz10 16/32] ms/percpu: cast percpu pointer in PERCPU_PTR() via unsigned long

[Konstantin Khorenko]

From: Uros Bizjak <ubizjak at gmail.com>

Cast pointer from percpu address space to generic (kernel) address space
in PERCPU_PTR() macro via unsigned long intermediate cast [1].  This
intermediate cast is also required to avoid build failure when GCC's
strict named address space checks for x86 targets [2] are enabled.

Found by GCC's named address space checks.

[1] https://sparse.docs.kernel.org/en/latest/annotations.html#address-space-name
[2] https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html#x86-Named-Address-Spaces

Link: https://lkml.kernel.org/r/20241021080856.48746-3-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak at gmail.com>
Acked-by: Christoph Lameter <cl at linux.com>
Cc: Dennis Zhou <dennis at kernel.org>
Cc: Tejun Heo <tj at kernel.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
(cherry picked from commit dabddd687c9e1a06241d6b4d1f66b9f2b60b3ad1)

Conflict resolution: the previous patch of the same upstream series had
to drop the stray trailing semicolon of PERCPU_PTR() to stay buildable
here, so only the body of the macro is replaced.

https://virtuozzo.atlassian.net/browse/VSTOR-134732
Feature: fix rh/sched
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 include/linux/percpu-defs.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index 02bcd74afc6c..ee236ee0bed6 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -221,7 +221,10 @@ do {									\
 } while (0)
 
 #define PERCPU_PTR(__p)							\
-	(typeof(*(__p)) __force __kernel *)(__p)
+({									\
+	unsigned long __pcpu_ptr = (__force unsigned long)(__p);	\
+	(typeof(*(__p)) __force __kernel *)(__pcpu_ptr);		\
+})
 
 #ifdef CONFIG_SMP
 
-- 
2.47.1