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[libcpu][am335x] Fix the booting failure when enabling MMU 

Since the 16 domains are configured as the client domains in
mmu_setttbase(), a Permission fault is generated if the XN bit
(Execute-never) is set in the short-descriptor translation table
(for section and supersection). This leads to the booting failure
when enabling MMU for beagleboard bsp. Here is log:

----------------------------------------------------------------
SD/MMC found on device 0
reading uEnv.txt
117 bytes read in 3 ms (38.1 KiB/s)
Loaded environment from uEnv.txt
Importing environment from mmc ...
Running uenvcmd ...
reading rtthread.bin
162624 bytes read in 24 ms (6.5 MiB/s)
\## Starting application at 0x80200000 ...

----------------------------------------------------------------

This commit removes the XN bit configuration in the section of the
short-descriptor translation table. The OS can be booted successfully
with applying this commit.
This commit is contained in:
Adrian Huang 2015-05-11 09:57:12 +08:00
parent 9fa2a04a64
commit 4222677933
1 changed files with 1 additions and 1 deletions
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2
libcpu/arm/am335x/mmu.c
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@ -15,7 +15,7 @@
#include <rtthread.h> #include <rtthread.h>
#include "am33xx.h" #include "am33xx.h"
#define DESC_SEC (0x2|(1<<4)) #define DESC_SEC (0x2)
#define CB (3<<2) //cache_on, write_back #define CB (3<<2) //cache_on, write_back
#define CNB (2<<2) //cache_on, write_through #define CNB (2<<2) //cache_on, write_through
#define NCB (1<<2) //cache_off,WR_BUF on #define NCB (1<<2) //cache_off,WR_BUF on