linux/arch/arm/mm/proc-macros.S
Russell King 22b1908610 [ARM] nommu: provide a way for correct control register value selection
Most MMU-based CPUs have a restriction on the setting of the data cache
enable and mmu enable bits in the control register, whereby if the data
cache is enabled, the MMU must also be enabled.  Enabling the data
cache without the MMU is an invalid combination.

However, there are CPUs where the data cache can be enabled without the
MMU.

In order to allow these CPUs to take advantage of that, provide a
method whereby each proc-*.S file defines the control regsiter value
for use with nommu (with the MMU disabled.)  Later on, when we add
support for enabling the MMU on these devices, we can adjust the
"crval" macro to also enable the data cache for nommu.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-06-29 15:09:57 +01:00

61 lines
994 B
ArmAsm

/*
* We need constants.h for:
* VMA_VM_MM
* VMA_VM_FLAGS
* VM_EXEC
*/
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
/*
* vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
*/
.macro vma_vm_mm, rd, rn
ldr \rd, [\rn, #VMA_VM_MM]
.endm
/*
* vma_vm_flags - get vma->vm_flags
*/
.macro vma_vm_flags, rd, rn
ldr \rd, [\rn, #VMA_VM_FLAGS]
.endm
.macro tsk_mm, rd, rn
ldr \rd, [\rn, #TI_TASK]
ldr \rd, [\rd, #TSK_ACTIVE_MM]
.endm
/*
* act_mm - get current->active_mm
*/
.macro act_mm, rd
bic \rd, sp, #8128
bic \rd, \rd, #63
ldr \rd, [\rd, #TI_TASK]
ldr \rd, [\rd, #TSK_ACTIVE_MM]
.endm
/*
* mmid - get context id from mm pointer (mm->context.id)
*/
.macro mmid, rd, rn
ldr \rd, [\rn, #MM_CONTEXT_ID]
.endm
/*
* mask_asid - mask the ASID from the context ID
*/
.macro asid, rd, rn
and \rd, \rn, #255
.endm
.macro crval, clear, mmuset, ucset
#ifdef CONFIG_MMU
.word \clear
.word \mmuset
#else
.word \clear
.word \ucset
#endif
.endm