From 57e26e57454fae4f1d15c2e9fa965b7a8046ab34 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 1 Nov 2013 10:46:40 +0530 Subject: ARC: [SMP] Fix build failures for large NR_CPUS ST.as only takes S9 (255) for offset. This was going out of range when accessing a task_struct field with 4k NR_CPUS (due to 128b of coumaks itself in there). Workaround by using an intermediate register to do the address scaling. There is some duplication of fix for ctx_sw.c and ctx_sw_asm.S however given that C version will go away soon I'm not bothering to factor out the common code. Reported-by: Noam Camus Signed-off-by: Vineet Gupta --- arch/arc/kernel/ctx_sw_asm.S | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'arch/arc/kernel/ctx_sw_asm.S') diff --git a/arch/arc/kernel/ctx_sw_asm.S b/arch/arc/kernel/ctx_sw_asm.S index d8972345e4c2..65690e7fcc8c 100644 --- a/arch/arc/kernel/ctx_sw_asm.S +++ b/arch/arc/kernel/ctx_sw_asm.S @@ -14,6 +14,8 @@ #include #include +#define KSP_WORD_OFF ((TASK_THREAD + THREAD_KSP) / 4) + ;################### Low Level Context Switch ########################## .section .sched.text,"ax",@progbits @@ -28,8 +30,13 @@ __switch_to: SAVE_CALLEE_SAVED_KERNEL /* Save the now KSP in task->thread.ksp */ - st.as sp, [r0, (TASK_THREAD + THREAD_KSP)/4] - +#if KSP_WORD_OFF <= 255 + st.as sp, [r0, KSP_WORD_OFF] +#else + /* Workaround for NR_CPUS=4k as ST.as can only take s9 offset */ + add2 r24, r0, KSP_WORD_OFF + st sp, [r24] +#endif /* * Return last task in r0 (return reg) * On ARC, Return reg = First Arg reg = r0. -- cgit v1.2.1