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MIPS: MAAR: Fix address alignment
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The alignment of MIPS MAAR region addresses isn't quite right.

- It rounds an already 64 KiB aligned start address up to the next
  64 KiB boundary, e.g. 0x80000000 is rounded up to 0x80010000.

- It assumes the end address is already on a 64 KiB boundary and doesn't
  round it down. Should that not be the case it will hit the second
  BUG_ON() in write_maar_pair().

Both cases are addressed by rounding up and down to 64 KiB boundaries in
the more traditional way of adding 0xffff (for rounding up) and masking
off the low 16 bits.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13858/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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James Hogan authored and Ralf Baechle committed Sep 13, 2016
1 parent 58cae9b commit ac7e385
Showing 1 changed file with 6 additions and 7 deletions.
13 changes: 6 additions & 7 deletions arch/mips/mm/init.c
Original file line number Diff line number Diff line change
@@ -261,7 +261,6 @@ unsigned __weak platform_maar_init(unsigned num_pairs)
{
struct maar_config cfg[BOOT_MEM_MAP_MAX];
unsigned i, num_configured, num_cfg = 0;
phys_addr_t skip;

for (i = 0; i < boot_mem_map.nr_map; i++) {
switch (boot_mem_map.map[i].type) {
@@ -272,14 +271,14 @@ unsigned __weak platform_maar_init(unsigned num_pairs)
continue;
}

skip = 0x10000 - (boot_mem_map.map[i].addr & 0xffff);

/* Round lower up */
cfg[num_cfg].lower = boot_mem_map.map[i].addr;
cfg[num_cfg].lower += skip;
cfg[num_cfg].lower = (cfg[num_cfg].lower + 0xffff) & ~0xffff;

cfg[num_cfg].upper = cfg[num_cfg].lower;
cfg[num_cfg].upper += boot_mem_map.map[i].size - 1;
cfg[num_cfg].upper -= skip;
/* Round upper down */
cfg[num_cfg].upper = boot_mem_map.map[i].addr +
boot_mem_map.map[i].size;
cfg[num_cfg].upper = (cfg[num_cfg].upper & ~0xffff) - 1;

cfg[num_cfg].attrs = MIPS_MAAR_S;
num_cfg++;

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