[PATCH] ARM: Fix get_cycles() after delay_read_timer() conversion

From: Nathan Chancellor

Date: Wed Aug 19 2026 - 17:43:35 EST


After commit dfc256dac54c ("calibrate: Rework delay timer calibration"),
certain ARM configurations (such as multi_v5_defconfig) hang during
boot. The use of read_current_timer() in arch/arm's get_cycles() was
improperly converted to delay_read_timer(), resulting in get_cycles()
returning 0 even when the timer has been read or an uninitialized stack
value when delay_read_timer() returns false.

Flip the branches of the ternary condition to fix get_cycles().

Fixes: dfc256dac54c ("calibrate: Rework delay timer calibration")
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
arch/arm/include/asm/timex.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/timex.h b/arch/arm/include/asm/timex.h
index 94e40c19cfc5..4d31eab9dba2 100644
--- a/arch/arm/include/asm/timex.h
+++ b/arch/arm/include/asm/timex.h
@@ -13,7 +13,7 @@ typedef unsigned long cycles_t;
// Temporary workaround until timex.h is cleaned up
bool delay_read_timer(unsigned long *t);

-#define get_cycles() ({ cycles_t c; delay_read_timer(&c) ? 0 : c; })
+#define get_cycles() ({ cycles_t c; delay_read_timer(&c) ? c : 0; })
#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback())

#endif

---
base-commit: dfc256dac54c8b692110bf905c64cb130e15963d
change-id: 20260819-fix-arm-get_cycles-c83096ec81a9

Best regards,
--
Cheers,
Nathan