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ARM: LPAE: factor out T1SZ and TTBR1 computations

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This patch moves the TTBR1 offset calculation and the T1SZ calculation out
of the TTB setup assembly code.  This should not affect functionality in
any way, but improves code readability as well as readability of subsequent
patches in this series.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Subash Patel <subash.rp@samsung.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Cyril Chemparathy 2012-07-21 19:47:52 -04:00 committed by Will Deacon
parent 1fc84ae84b
commit a7fbc0d62a
2 changed files with 28 additions and 21 deletions
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20
arch/arm/include/asm/pgtable-3level-hwdef.h
View File

@ -79,4 +79,24 @@
#define PHYS_MASK_SHIFT (40)
#define PHYS_MASK ((1ULL << PHYS_MASK_SHIFT) - 1)
/*
* TTBR0/TTBR1 split (PAGE_OFFSET):
* 0x40000000: T0SZ = 2, T1SZ = 0 (not used)
* 0x80000000: T0SZ = 0, T1SZ = 1
* 0xc0000000: T0SZ = 0, T1SZ = 2
*
* Only use this feature if PHYS_OFFSET <= PAGE_OFFSET, otherwise
* booting secondary CPUs would end up using TTBR1 for the identity
* mapping set up in TTBR0.
*/
#if defined CONFIG_VMSPLIT_2G
#define TTBR1_OFFSET 16 /* skip two L1 entries */
#elif defined CONFIG_VMSPLIT_3G
#define TTBR1_OFFSET (4096 * (1 + 3)) /* only L2, skip pgd + 3*pmd */
#else
#define TTBR1_OFFSET 0
#endif
#define TTBR1_SIZE (((PAGE_OFFSET >> 30) - 1) << 16)
#endif

29
arch/arm/mm/proc-v7-3level.S
View File

@ -114,7 +114,7 @@ ENDPROC(cpu_v7_set_pte_ext)
*/
.macro v7_ttb_setup, zero, ttbr0, ttbr1, tmp
ldr \tmp, =swapper_pg_dir @ swapper_pg_dir virtual address
cmp \ttbr1, \tmp @ PHYS_OFFSET > PAGE_OFFSET? (branch below)
cmp \ttbr1, \tmp @ PHYS_OFFSET > PAGE_OFFSET?
mrc p15, 0, \tmp, c2, c0, 2 @ TTB control register
orr \tmp, \tmp, #TTB_EAE
ALT_SMP(orr \tmp, \tmp, #TTB_FLAGS_SMP)
@ -122,27 +122,14 @@ ENDPROC(cpu_v7_set_pte_ext)
ALT_SMP(orr \tmp, \tmp, #TTB_FLAGS_SMP << 16)
ALT_UP(orr \tmp, \tmp, #TTB_FLAGS_UP << 16)
/*
* TTBR0/TTBR1 split (PAGE_OFFSET):
* 0x40000000: T0SZ = 2, T1SZ = 0 (not used)
* 0x80000000: T0SZ = 0, T1SZ = 1
* 0xc0000000: T0SZ = 0, T1SZ = 2
*
* Only use this feature if PHYS_OFFSET <= PAGE_OFFSET, otherwise
* booting secondary CPUs would end up using TTBR1 for the identity
* mapping set up in TTBR0.
* Only use split TTBRs if PHYS_OFFSET <= PAGE_OFFSET (cmp above),
* otherwise booting secondary CPUs would end up using TTBR1 for the
* identity mapping set up in TTBR0.
*/
bhi 9001f @ PHYS_OFFSET > PAGE_OFFSET?
orr \tmp, \tmp, #(((PAGE_OFFSET >> 30) - 1) << 16) @ TTBCR.T1SZ
#if defined CONFIG_VMSPLIT_2G
/* PAGE_OFFSET == 0x80000000, T1SZ == 1 */
add \ttbr1, \ttbr1, #1 << 4 @ skip two L1 entries
#elif defined CONFIG_VMSPLIT_3G
/* PAGE_OFFSET == 0xc0000000, T1SZ == 2 */
add \ttbr1, \ttbr1, #4096 * (1 + 3) @ only L2 used, skip pgd+3*pmd
#endif
/* CONFIG_VMSPLIT_1G does not need TTBR1 adjustment */
9001: mcr p15, 0, \tmp, c2, c0, 2 @ TTB control register
mcrr p15, 1, \ttbr1, \zero, c2 @ load TTBR1
orrls \tmp, \tmp, #TTBR1_SIZE @ TTBCR.T1SZ
mcr p15, 0, \tmp, c2, c0, 2 @ TTBCR
addls \ttbr1, \ttbr1, #TTBR1_OFFSET
mcrr p15, 1, \ttbr1, \zero, c2 @ load TTBR1
.endm
__CPUINIT