Commit graph

8 commits

Author SHA1 Message Date
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
Michal Simek
1451d1d88b microblaze: Introduce TLB skip size
TLB skip size direct how many TLBs is skipped.
Currently TLB0 and TLB1 are used for Linux kernel mapping
that's why their are skipped.

Signed-off-by: Michal Simek <monstr@monstr.eu>
2012-03-23 09:28:18 +01:00
Michal Simek
af58ed854b microblaze: Fix comment for TLB
There is wrong comment for TLB. Early printk uartlite
console uses TLB 63.

Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-08-02 10:44:03 +02:00
Michal Simek
43f2a6e8b1 microblaze: Remove "cache" optimized copy_page function
Current implementation doesn't handle dcache_line_length
correctly that's why is better to use generic memcpy.

Cache optimized function could be good way howto improve
performance but must be based on benchmarking not blind
function like this.

Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-05-06 11:21:58 +02:00
Michal Simek
0691c97d74 microblaze: Use MICROBLAZE_TLB_SIZE in asm code
TLB size was hardcoded in asm code. This patch brings ability
to change TLB size only in one place. (mmu.h).

Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-04-01 08:38:24 +02:00
Michal Simek
13851966da microblaze: Add .type and .size to ASM functions
Cachegrind analysis need this fix to be able to log asm functions.

Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-04-01 08:38:24 +02:00
Michal Simek
fee3c55d7f microblaze: Fix problem with early_printk in startup
Problem arise when is incopatibility between kernel/dts/pvr
and kernel tries to announce it. Early printk device
(uartlite in our case) was in TLB 2 and when kernel
extract DTB it necessary to allocate at least one
TLB at the end of memory. First free TLB was number two
where was early printk. But checking mechanism (kernel/dts/pvr)
was after extrahing but TLB 2 was different. This caused
that kernel hung up.
Moving early printk device to TLB 63 solve it and we don't
protect it which means that we can use early_printk messages
only for initial parts of kernel then we rewrite TLB 63.

Reported-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-05-30 16:40:58 +02:00
Michal Simek
3f50425c0c microblaze_mmu_v2: TLB low level code
Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-05-26 16:45:14 +02:00