From 6b1370ae392b79ac3e2d053205f4107d4a55c102 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Thu, 18 Apr 2019 11:33:13 +0200 Subject: parisc: enable wide mode early The idle task might have been allocated above 4GB. With the current code we cannot access that memory because the CPU is still running in narrow mode. This was found on a J5000 machine and the patch is required to enable SPARSEMEM on that machine. Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller --- arch/parisc/kernel/head.S | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S index fbb4e43fda05..fefaba2097b5 100644 --- a/arch/parisc/kernel/head.S +++ b/arch/parisc/kernel/head.S @@ -329,6 +329,19 @@ smp_slave_stext: mtsp %r0,%sr6 mtsp %r0,%sr7 +#ifdef CONFIG_64BIT + /* + * Enable Wide mode early, in case the task_struct for the idle + * task in smp_init_current_idle_task was allocated above 4GB. + */ +1: mfia %rp /* clear upper part of pcoq */ + ldo 2f-1b(%rp),%rp + depdi 0,31,32,%rp + bv (%rp) + ssm PSW_SM_W,%r0 +2: +#endif + /* Initialize the SP - monarch sets up smp_init_current_idle_task */ load32 PA(smp_init_current_idle_task),%sp LDREG 0(%sp),%sp /* load task address */ -- cgit v1.2.3