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sparc32: mm: Restructure sparc32 MMU page-table layout

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The "SRMMU" supports 4k pages using a fixed three-level walk with a
256-entry PGD and 64-entry PMD/PTE levels. In order to fill a page
with a 'pgtable_t', the SRMMU code allocates four native PTE tables
into a single PTE allocation and similarly for the PMD level, leading
to an array of 16 physical pointers in a 'pmd_t'

This breaks the generic code which assumes READ_ONCE(*pmd) will be
word sized.

In a manner similar to ef22d8abd8 ("m68k: mm: Restructure Motorola
MMU page-table layout"), this patch implements the native page-table
setup directly. This significantly increases the page-table memory
overhead, but will be addresses in a subsequent patch.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Will Deacon
2020-04-14 22:40:09 +01:00
committed by David S. Miller
parent ed894bf5a7
commit 8e958839e4
9 changed files with 58 additions and 103 deletions
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8
arch/sparc/kernel/head_32.S
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@@ -24,7 +24,7 @@
#include <asm/winmacro.h>
#include <asm/thread_info.h> /* TI_UWINMASK */
#include <asm/errno.h>
#include <asm/pgtsrmmu.h> /* SRMMU_PGDIR_SHIFT */
#include <asm/pgtable.h> /* PGDIR_SHIFT */
#include <asm/export.h>
.data
@@ -273,7 +273,7 @@ not_a_sun4:
lda [%o1] ASI_M_BYPASS, %o2 ! This is the 0x0 16MB pgd
/* Calculate to KERNBASE entry. */
add %o1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %o3
add %o1, KERNBASE >> (PGDIR_SHIFT - 2), %o3
/* Poke the entry into the calculated address. */
sta %o2, [%o3] ASI_M_BYPASS
@@ -317,7 +317,7 @@ srmmu_not_viking:
sll %g1, 0x8, %g1 ! make phys addr for l1 tbl
lda [%g1] ASI_M_BYPASS, %g2 ! get level1 entry for 0x0
add %g1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %g3
add %g1, KERNBASE >> (PGDIR_SHIFT - 2), %g3
sta %g2, [%g3] ASI_M_BYPASS ! place at KERNBASE entry
b go_to_highmem
nop ! wheee....
@@ -341,7 +341,7 @@ leon_remap:
sll %g1, 0x8, %g1 ! make phys addr for l1 tbl
lda [%g1] ASI_M_BYPASS, %g2 ! get level1 entry for 0x0
add %g1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %g3
add %g1, KERNBASE >> (PGDIR_SHIFT - 2), %g3
sta %g2, [%g3] ASI_M_BYPASS ! place at KERNBASE entry
b go_to_highmem
nop ! wheee....