[PATCH 1/2] arm_mpam: Force __iomem casts
From: Krzysztof Kozlowski
Date: Mon Feb 16 2026 - 06:03:30 EST
Code allocates standard kernel memory to pass to the MPAM, which expects
__iomem. The code is safe, because __iomem accessors should work fine
on kernel mapped memory, however leads to sparse warnings:
test_mpam_devices.c:327:42: warning: incorrect type in initializer (different address spaces)
test_mpam_devices.c:327:42: expected char [noderef] __iomem *buf
test_mpam_devices.c:327:42: got void *
test_mpam_devices.c:342:24: warning: cast removes address space '__iomem' of expression
Cast the pointer to memory via __force to silence them.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
---
drivers/resctrl/test_mpam_devices.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/resctrl/test_mpam_devices.c b/drivers/resctrl/test_mpam_devices.c
index 3e8d564a0c64..2de41b47c138 100644
--- a/drivers/resctrl/test_mpam_devices.c
+++ b/drivers/resctrl/test_mpam_devices.c
@@ -324,7 +324,7 @@ static void test_mpam_enable_merge_features(struct kunit *test)
static void test_mpam_reset_msc_bitmap(struct kunit *test)
{
- char __iomem *buf = kunit_kzalloc(test, SZ_16K, GFP_KERNEL);
+ char __iomem *buf = (__force char __iomem *)kunit_kzalloc(test, SZ_16K, GFP_KERNEL);
struct mpam_msc fake_msc = {};
u32 *test_result;
@@ -339,7 +339,7 @@ static void test_mpam_reset_msc_bitmap(struct kunit *test)
mutex_init(&fake_msc.part_sel_lock);
mutex_lock(&fake_msc.part_sel_lock);
- test_result = (u32 *)(buf + MPAMCFG_CPBM);
+ test_result = (__force u32 *)(buf + MPAMCFG_CPBM);
mpam_reset_msc_bitmap(&fake_msc, MPAMCFG_CPBM, 0);
KUNIT_EXPECT_EQ(test, test_result[0], 0);
--
2.51.0