diff options
Diffstat (limited to 'bsps/powerpc/shared/start/pgtbl_setup.c')
| -rw-r--r-- | bsps/powerpc/shared/start/pgtbl_setup.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/bsps/powerpc/shared/start/pgtbl_setup.c b/bsps/powerpc/shared/start/pgtbl_setup.c new file mode 100644 index 0000000000..8a8407bd49 --- /dev/null +++ b/bsps/powerpc/shared/start/pgtbl_setup.c @@ -0,0 +1,135 @@ +#include <rtems.h> +#include <libcpu/mmu.h> +#include <rtems/bspIo.h> +#include <libcpu/pte121.h> + +/* Default setup of the page tables. This is a weak + * alias, so applications may easily override this + * default setup. + * + * NOTE: while it is possible to change the individual + * mappings, the page table itself MUST be + * allocated at the top of the physical memory! + * bspstart.c RELIES on this. + * Also, the 'setup' routine must reduce + * *pmemsize by the size of the page table. + */ +/* to align the pointer to the (next) page boundary */ +#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) + + +/* + * Authorship + * ---------- + * This software was created by + * Till Straumann <strauman@slac.stanford.edu>, 4/2002, + * Stanford Linear Accelerator Center, Stanford University. + * + * Acknowledgement of sponsorship + * ------------------------------ + * This software was produced by + * the Stanford Linear Accelerator Center, Stanford University, + * under Contract DE-AC03-76SFO0515 with the Department of Energy. + * + * Government disclaimer of liability + * ---------------------------------- + * Neither the United States nor the United States Department of Energy, + * nor any of their employees, makes any warranty, express or implied, or + * assumes any legal liability or responsibility for the accuracy, + * completeness, or usefulness of any data, apparatus, product, or process + * disclosed, or represents that its use would not infringe privately owned + * rights. + * + * Stanford disclaimer of liability + * -------------------------------- + * Stanford University makes no representations or warranties, express or + * implied, nor assumes any liability for the use of this software. + * + * Stanford disclaimer of copyright + * -------------------------------- + * Stanford University, owner of the copyright, hereby disclaims its + * copyright and all other rights in this software. Hence, anyone may + * freely use it for any purpose without restriction. + * + * Maintenance of notices + * ---------------------- + * In the interest of clarity regarding the origin and status of this + * SLAC software, this and all the preceding Stanford University notices + * are to remain affixed to any copy or derivative of this software made + * or distributed by the recipient and are to be affixed to any copy of + * software made or distributed by the recipient that contains a copy or + * derivative of this software. + * + * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03 + */ + +Triv121PgTbl __BSP_default_pgtbl_setup(unsigned int *pmemsize); +Triv121PgTbl BSP_pgtbl_setup(unsigned int *) + __attribute__ (( weak, alias("__BSP_default_pgtbl_setup") )); + +/* get those from the linker script. + * NOTE THAT THE CORRECTNESS OF THE LINKER SCRIPT IS CRUCIAL + */ +extern unsigned long __DATA_START__[], _etext[]; + +Triv121PgTbl +__BSP_default_pgtbl_setup(unsigned int *pmemsize) +{ +Triv121PgTbl pt; +unsigned ldPtSize,tmp; + + /* Allocate a page table large enough to map + * the entire physical memory. We put the page + * table at the top of the physical memory. + */ + + /* get minimal size (log base 2) of PT for + * this board's memory + */ + ldPtSize = triv121PgTblLdMinSize(*pmemsize); + ldPtSize++; /* double this amount -- then why? */ + + /* allocate the page table at the top of the physical + * memory - THIS IS NOT AN OPTION - bspstart.c RELIES + * ON THIS LAYOUT! (the size, however may be changed) + */ + if ( (pt = triv121PgTblInit(*pmemsize - (1<<ldPtSize), ldPtSize)) ) { + /* map text and RO data read-only */ + tmp = triv121PgTblMap( + pt, + TRIV121_121_VSID, + 0, + (PAGE_ALIGN((unsigned long)_etext) - 0) >> PG_SHIFT, + 0, /* WIMG */ + TRIV121_PP_RO_PAGE); + if (TRIV121_MAP_SUCCESS != tmp) { + printk("Unable to map page index %i; reverting to BAT0\n", + tmp); + pt = 0; + } else { + /* map the rest (without the page table itself) RW */ + tmp = triv121PgTblMap( + pt, + TRIV121_121_VSID, + (unsigned long)__DATA_START__, + (*pmemsize - (1<<ldPtSize) - (unsigned long)__DATA_START__ )>> PG_SHIFT, + 0, /* WIMG */ + TRIV121_PP_RW_PAGE); + if (TRIV121_MAP_SUCCESS != tmp) { + printk("Unable to map page index %i; reverting to BAT0\n", + tmp); + pt = 0; + } + } + } else { + printk("WARNING: unable to allocate page table, keeping DBAT0\n"); + } + if (pt) { +#ifdef SHOW_MORE_INIT_SETTINGS + printk("Setting up page table mappings; protecting text/read-only data from write access\n"); +#endif + /* SUCCESS; reduce available memory by size of the page table */ + *pmemsize -= (1<<ldPtSize); + } + return pt; +} |