diff options
| author |   John David Anglin <dave.anglin@bell.net> | 2022-05-15 22:47:04 +0000 |
|---|---|---|
| committer |   Helge Deller <deller@gmx.de> | 2022-05-23 13:44:24 +0200 |
| commit | c64c782e58ac5bb3601aa77b860ca4e93a489b7a (patch) | |
| tree | 558b8d00de302eb8476331c37b83ea9135fc2ab2 /arch/parisc/include/asm | |
| parent | parisc: Don't enforce DMA completion order in cache flushes (diff) | |
| download | linux-dev-c64c782e58ac5bb3601aa77b860ca4e93a489b7a.tar.xz linux-dev-c64c782e58ac5bb3601aa77b860ca4e93a489b7a.zip | |
parisc: Don't hardcode assembler bit definitions in tmpalias code
Remove the hardcoded bit definitions in the tmpalias assembly code.
This makes it easy to change the size of the tmpalias region.
The alignment of the tmpalias region is reduced from 16 MB to 8 MB.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc/include/asm')
| -rw-r--r-- | arch/parisc/include/asm/fixmap.h | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/arch/parisc/include/asm/fixmap.h b/arch/parisc/include/asm/fixmap.h index e480b2c05407..5cd80ce1163a 100644 --- a/arch/parisc/include/asm/fixmap.h +++ b/arch/parisc/include/asm/fixmap.h @@ -9,12 +9,27 @@ * * All of the values in this file must be <4GB (because of assembly * loading restrictions). If you place this region anywhere above - * __PAGE_OFFSET, you must adjust the memory map accordingly */ + * __PAGE_OFFSET, you must adjust the memory map accordingly + */ -/* The alias region is used in kernel space to do copy/clear to or - * from areas congruently mapped with user space. It is 8MB large - * and must be 16MB aligned */ -#define TMPALIAS_MAP_START ((__PAGE_OFFSET) - 16*1024*1024) +/* + * The tmpalias region is used in kernel space to copy/clear/flush data + * from pages congruently mapped with user space. It is comprised of + * a pair regions. The size of these regions is determined by the largest + * cache aliasing boundary for machines that support equivalent aliasing. + * + * The c3750 with PA8700 processor returns an alias value of 11. This + * indicates that it has an alias boundary of 4 MB. It also supports + * non-equivalent aliasing without a performance penalty. + * + * Machines with PA8800/PA8900 processors return an alias value of 0. + * This indicates the alias boundary is unknown and may be larger than + * 16 MB. Non-equivalent aliasing is not supported. + * + * Here we assume the maximum alias boundary is 4 MB. + */ +#define TMPALIAS_SIZE_BITS 22 /* 4 MB */ +#define TMPALIAS_MAP_START ((__PAGE_OFFSET) - (2 << TMPALIAS_SIZE_BITS)) #define FIXMAP_SIZE (FIX_BITMAP_COUNT << PAGE_SHIFT) #define FIXMAP_START (TMPALIAS_MAP_START - FIXMAP_SIZE) |