diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-10-04 17:51:54 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-10-08 10:07:34 +0100 |
| commit | 786f1b73f7d5cad5c88dc75a96d53a74160aa7d7 (patch) | |
| tree | 1a8004c1a1b74060f283d6b042fe3c1c495f22a8 | |
| parent | 80924ac595f3ca32ec0a80cc1217c7019d3519ff (diff) | |
ARM: hotplug cpu: ensure that __enable_mmu is identity mapped
__enable_mmu is required to be executed in an identity mapped region
to ensure that variances in CPUs do not cause a crash. We currently
achieve this by assuming that it will be co-located with
__create_page_tables. With hotplug CPU support, this assumption
becomes invalid. Implement a better solution which ensures that
it will be appropriately mapped no matter where it is placed.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| -rw-r--r-- | arch/arm/kernel/head.S | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index aa6ab9d8646..17414e29948 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -201,6 +201,7 @@ __turn_mmu_on: mov r3, r3 mov r3, r13 mov pc, r3 +__enable_mmu_end: ENDPROC(__turn_mmu_on) @@ -214,7 +215,7 @@ ENDPROC(__turn_mmu_on) * r10 = procinfo * * Returns: - * r0, r3, r6, r7 corrupted + * r0, r3, r5-r7 corrupted * r4 = physical page table address */ __create_page_tables: @@ -236,20 +237,30 @@ __create_page_tables: ldr r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags /* - * Create identity mapping for first MB of kernel to - * cater for the MMU enable. This identity mapping - * will be removed by paging_init(). We use our current program - * counter to determine corresponding section base address. + * Create identity mapping to cater for __enable_mmu. + * This identity mapping will be removed by paging_init(). */ - mov r6, pc - mov r6, r6, lsr #20 @ start of kernel section - orr r3, r7, r6, lsl #20 @ flags + kernel base - str r3, [r4, r6, lsl #2] @ identity mapping + adr r0, __enable_mmu_loc + ldmia r0, {r3, r5, r6} + sub r0, r0, r3 @ virt->phys offset + add r5, r5, r0 @ phys __enable_mmu + add r6, r6, r0 @ phys __enable_mmu_end + mov r5, r5, lsr #20 + mov r6, r6, lsr #20 + +1: orr r3, r7, r5, lsl #20 @ flags + kernel base + str r3, [r4, r5, lsl #2] @ identity mapping + teq r5, r6 + addne r5, r5, #1 @ next section + bne 1b /* * Now setup the pagetables for our kernel direct * mapped region. */ + mov r3, pc + mov r3, r3, lsr #20 + orr r3, r7, r3, lsl #20 add r0, r4, #(KERNEL_START & 0xff000000) >> 18 str r3, [r0, #(KERNEL_START & 0x00f00000) >> 18]! ldr r6, =(KERNEL_END - 1) @@ -333,5 +344,9 @@ __create_page_tables: mov pc, lr ENDPROC(__create_page_tables) .ltorg +__enable_mmu_loc: + .long . + .long __enable_mmu + .long __enable_mmu_end #include "head-common.S" |