percpu: cast percpu pointer in PERCPU_PTR() via unsigned long

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@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index e1cf7982424f18c17198965f3787d34ac644ce5a..35842d1e38796c8915aae26dad4ce2f48b91d1a8 100644 (file)
--- 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