Michal Simek e02db0aa3e microblaze: Handle TLB skip size dynamically ... This patch fix the problem with rootfs on JFFS2 with early printk console turned on. The origin version used TLB63 for temporary early printk mapping. The code expect that kernel is not able to use all 64 TLB entries till early printk console is remapped by ioremap. After that temporary mapping on TLB63 is silently lost. This expectation give the opportunity to have early console pretty early. Microblaze systems with JFFS2 rootfs with early printk console turned on used more than 64 TLB entries before kernel can remap early console. Based on that kernel does access to bad area because early printk mapping is rewritten. This patch introduces tlb_skip variable which dynamically stores number of skipped TLB entries from the TLB0. skip_tlb=2 means that TLB0 and TLB1 should be skipped. MICROBLAZE_TLB_SKIP defines how many TLB is skipped at the kernel start. They can be used for user purpose. TLB 63 is used for temporary LMB mapping (MICROBLAZE_LMB_TLB_ID). Also clean TLBLO when kernel starts. For specific kernel sizes kernel can use just one TLB. Detect this case and use the second TLB for general purpose. Change _tlbia function to flush TLB entries from tlb_skip to TLB_SIZE. Export tlb_skip size through debugfs. Signed-off-by: Michal Simek <monstr@monstr.eu>		2012-03-23 09:28:19 +01:00
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asm	microblaze: Handle TLB skip size dynamically	2012-03-23 09:28:19 +01:00