From: Michal Simek Date: Wed, 9 Nov 2011 14:39:58 +0000 (+0100) Subject: microblaze: Clear all MSR flags on the first kernel instruction X-Git-Tag: v3.4-rc1~82^2~4 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=173701d7745d07888a929bf08d77d29996ca13dc;p=linux.git microblaze: Clear all MSR flags on the first kernel instruction The main reason is bug because of dynamic TLB allocation. U-BOOT didn't disable dcache and then writing to physical address from ASM wan't visible for reading through MMU. Disabling caches and clearing all flags from previous code is good to do so. Signed-off-by: Michal Simek --- diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index 77320b8fc16a..a5ba9925ae89 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -63,9 +63,7 @@ ENTRY(_start) real_start: #endif - mfs r1, rmsr - andi r1, r1, ~2 - mts rmsr, r1 + mts rmsr, r0 /* * According to Xilinx, msrclr instruction behaves like 'mfs rX,rpc' * if the msrclr instruction is not enabled. We use this to detect @@ -73,6 +71,7 @@ real_start: * r8 == 0 - msr instructions are implemented * r8 != 0 - msr instructions are not implemented */ + mfs r1, rmsr msrclr r8, 0 /* clear nothing - just read msr for test */ cmpu r8, r8, r1 /* r1 must contain msr reg content */