From 717321fcb58ed95169bf344ae47ac6098ba5dfbe Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 4 Nov 2013 20:14:58 +0000 Subject: [PATCH] arm64: fix access to preempt_count from assembly code preempt_count is defined as an int. Oddly enough, we access it as a 64bit value. Things become interesting when running a BE kernel, and looking at the current CPU number, which is stored as an int next to preempt_count. Like in a per-cpu interrupt handler, for example... Using a 32bit access fixes the issue for good. Cc: Matthew Leach Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas --- arch/arm64/kernel/entry.S | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 3881fd115ebb..e1166145ca29 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -311,14 +311,14 @@ el1_irq: #endif #ifdef CONFIG_PREEMPT get_thread_info tsk - ldr x24, [tsk, #TI_PREEMPT] // get preempt count - add x0, x24, #1 // increment it - str x0, [tsk, #TI_PREEMPT] + ldr w24, [tsk, #TI_PREEMPT] // get preempt count + add w0, w24, #1 // increment it + str w0, [tsk, #TI_PREEMPT] #endif irq_handler #ifdef CONFIG_PREEMPT - str x24, [tsk, #TI_PREEMPT] // restore preempt count - cbnz x24, 1f // preempt count != 0 + str w24, [tsk, #TI_PREEMPT] // restore preempt count + cbnz w24, 1f // preempt count != 0 ldr x0, [tsk, #TI_FLAGS] // get flags tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling? bl el1_preempt @@ -509,15 +509,15 @@ el0_irq_naked: #endif get_thread_info tsk #ifdef CONFIG_PREEMPT - ldr x24, [tsk, #TI_PREEMPT] // get preempt count - add x23, x24, #1 // increment it - str x23, [tsk, #TI_PREEMPT] + ldr w24, [tsk, #TI_PREEMPT] // get preempt count + add w23, w24, #1 // increment it + str w23, [tsk, #TI_PREEMPT] #endif irq_handler #ifdef CONFIG_PREEMPT - ldr x0, [tsk, #TI_PREEMPT] - str x24, [tsk, #TI_PREEMPT] - cmp x0, x23 + ldr w0, [tsk, #TI_PREEMPT] + str w24, [tsk, #TI_PREEMPT] + cmp w0, w23 b.eq 1f mov x1, #0 str x1, [x1] // BUG -- 2.20.1