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| author | Chris Zankel <chris@zankel.net> | 2007-08-06 23:57:57 -0700 |
|---|---|---|
| committer | Chris Zankel <chris@zankel.net> | 2007-08-27 13:54:01 -0700 |
| commit | 01858d1b0b406307626bbc01238391b06aae2c20 (patch) | |
| tree | d01d20f3f513e6a21880a60cdf195023e6aafc66 /arch/xtensa/kernel | |
| parent | 26465f2f4f5a253f22596fc9245a6bb5c0856ee1 (diff) | |
| download | op-kernel-dev-01858d1b0b406307626bbc01238391b06aae2c20.zip op-kernel-dev-01858d1b0b406307626bbc01238391b06aae2c20.tar.gz | |
[XTENSA] Add support for executable/non-executable feature in the mmu
Newer processor versions starting with Xtensa6/LX2 support an 'executable'
bit for memory pages. This bit replaces the 'valid' bit, so it must be
always set to one for older processor versions. To mark a page invalid, we now
set the cache-attributes to b11, which is backward compatible.
Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa/kernel')
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 42 |
1 files changed, 28 insertions, 14 deletions
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 8dc7a2c..65741e3 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1572,10 +1572,12 @@ ENTRY(fast_second_level_miss) l32i a0, a1, TASK_MM # tsk->mm beqz a0, 9f -8: rsr a1, EXCVADDR # fault address - _PGD_OFFSET(a0, a1, a1) + + /* We deliberately destroy a3 that holds the exception table. */ + +8: rsr a3, EXCVADDR # fault address + _PGD_OFFSET(a0, a3, a1) l32i a0, a0, 0 # read pmdval - //beqi a0, _PAGE_USER, 2f beqz a0, 2f /* Read ptevaddr and convert to top of page-table page. @@ -1596,20 +1598,34 @@ ENTRY(fast_second_level_miss) extui a1, a0, 0, PAGE_SHIFT # ... & PAGE_MASK xor a0, a0, a1 - - movi a1, PAGE_DIRECTORY + movi a1, _PAGE_DIRECTORY or a0, a0, a1 # ... | PAGE_DIRECTORY + /* + * We utilize all three wired-ways (7-9( to hold pmd translations. + * Memory regions are mapped to the DTLBs according to bits 28 and 29. + * This allows to map the three most common regions to three different + * DTLBs: + * 0,1 -> way 7 program (0040.0000) and virtual (c000.0000) + * 2 -> way 8 shared libaries (2000.0000) + * 3 -> way 0 stack (3000.0000) + */ + + extui a3, a3, 28, 2 # addr. bit 28 and 29 0,1,2,3 rsr a1, PTEVADDR + addx2 a3, a3, a3 # -> 0,3,6,9 srli a1, a1, PAGE_SHIFT + extui a3, a3, 2, 2 # -> 0,0,1,2 slli a1, a1, PAGE_SHIFT # ptevaddr & PAGE_MASK - addi a1, a1, DTLB_WAY_PGD # ... + way_number + addi a3, a3, DTLB_WAY_PGD + add a1, a1, a3 # ... + way_number - wdtlb a0, a1 +3: wdtlb a0, a1 dsync /* Exit critical section. */ +4: movi a3, exc_table # restore a3 movi a0, 0 s32i a0, a3, EXC_TABLE_FIXUP @@ -1638,6 +1654,7 @@ ENTRY(fast_second_level_miss) 2: /* Invalid PGD, default exception handling */ + movi a3, exc_table rsr a1, DEPC xsr a3, EXCSAVE_1 s32i a1, a2, PT_AREG2 @@ -1682,15 +1699,15 @@ ENTRY(fast_store_prohibited) 8: rsr a1, EXCVADDR # fault address _PGD_OFFSET(a0, a1, a4) l32i a0, a0, 0 - //beqi a0, _PAGE_USER, 2f # FIXME use _PAGE_INVALID beqz a0, 2f + /* Note that we assume _PAGE_WRITABLE_BIT is only set if pte is valid.*/ + _PTE_OFFSET(a0, a1, a4) l32i a4, a0, 0 # read pteval - movi a1, _PAGE_VALID | _PAGE_RW - bnall a4, a1, 2f + bbci.l a4, _PAGE_WRITABLE_BIT, 2f - movi a1, _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_WRENABLE + movi a1, _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_HW_WRITE or a4, a4, a1 rsr a1, EXCVADDR s32i a4, a0, 0 @@ -1700,10 +1717,7 @@ ENTRY(fast_store_prohibited) dhwb a0, 0 #endif pdtlb a0, a1 - beqz a0, 1f - idtlb a0 // FIXME do we need this? wdtlb a4, a0 -1: /* Exit critical section. */ |
