From mboxrd@z Thu Jan 1 00:00:00 1970 From: nomura@hpc.bs1.fc.nec.co.jp Date: Thu, 22 Nov 2001 11:36:47 +0000 Subject: [Linux-ia64] where to set rr for uncached region Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hello, Current code sets rr for region 6 (kernel uncached region) in ia64_mmu_init(). However, thinking about application processors, there are some printk()s before ia64_mmu_init() to be called. Since printk() ends up in vt_console_print() and store to uncached region will happen, I think this cause a problem. In reality, MCAs always happen on our machine after AP prints "CPU 1: mapping PAL code ..." to serial console. The processor log shows that MCA happend in vt_console_print() on CPU1. I can work around the problem by applying this patch. I've noticed the problem when EARLY_PRINTK was deleted from config option. So I'm curious about whether anyone has not experienced same kind of problem. diff -u -r1.1.1.8.6.1 head.S --- arch/ia64/kernel/head.S 2001/10/04 10:31:46 1.1.1.8.6.1 +++ arch/ia64/kernel/head.S 2001/10/05 02:18:17 @@ -111,7 +111,6 @@ mov ar.fpsr=r2 ;; -#ifdef CONFIG_IA64_EARLY_PRINTK mov r3=(6<<8) | (KERNEL_PG_SHIFT<<2) movl r2=6<<61 ;; @@ -119,7 +118,6 @@ ;; srlz.i ;; -#endif #define isAP p2 // are we an Application Processor? #define isBP p3 // are we the Bootstrap Processor? Best regards. -- NOMURA, Jun'ichi HPC Operating System Group, 1st Computers Software Division, Computers Software Operations Unit, NEC Solutions.