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yaml
---
r: 252367
b: refs/heads/master
c: 4c2896e
h: refs/heads/master
i:
  252365: 9b4c2c9
  252363: 8f3bb2b
  252359: 00cbcae
  252351: 164657c
v: v3
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Grant Likely committed May 11, 2011
1 parent 51e0ee8 commit a82f524
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Showing 3 changed files with 23 additions and 11 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 7ee4b98eca42c1ff1df7dcf443dac07f0a2ea93d
refs/heads/master: 4c2896e88d976d0e5b2213c64cde885f5677fa2b
24 changes: 18 additions & 6 deletions trunk/arch/arm/kernel/head-common.S
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,12 @@
#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
#define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2)

#ifdef CONFIG_CPU_BIG_ENDIAN
#define OF_DT_MAGIC 0xd00dfeed
#else
#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */
#endif

/*
* Exception handling. Something went wrong and we can't proceed. We
* ought to tell the user, but since we don't have any guarantee that
Expand All @@ -28,28 +34,34 @@

/* Determine validity of the r2 atags pointer. The heuristic requires
* that the pointer be aligned, in the first 16k of physical RAM and
* that the ATAG_CORE marker is first and present. Future revisions
* that the ATAG_CORE marker is first and present. If CONFIG_OF_FLATTREE
* is selected, then it will also accept a dtb pointer. Future revisions
* of this function may be more lenient with the physical address and
* may also be able to move the ATAGS block if necessary.
*
* Returns:
* r2 either valid atags pointer, or zero
* r2 either valid atags pointer, valid dtb pointer, or zero
* r5, r6 corrupted
*/
__vet_atags:
tst r2, #0x3 @ aligned?
bne 1f

ldr r5, [r2, #0] @ is first tag ATAG_CORE?
cmp r5, #ATAG_CORE_SIZE
ldr r5, [r2, #0]
#ifdef CONFIG_OF_FLATTREE
ldr r6, =OF_DT_MAGIC @ is it a DTB?
cmp r5, r6
beq 2f
#endif
cmp r5, #ATAG_CORE_SIZE @ is first tag ATAG_CORE?
cmpne r5, #ATAG_CORE_SIZE_EMPTY
bne 1f
ldr r5, [r2, #4]
ldr r6, =ATAG_CORE
cmp r5, r6
bne 1f

mov pc, lr @ atag pointer is ok
2: mov pc, lr @ atag/dtb pointer is ok

1: mov r2, #0
mov pc, lr
Expand All @@ -61,7 +73,7 @@ ENDPROC(__vet_atags)
*
* r0 = cp#15 control register
* r1 = machine ID
* r2 = atags pointer
* r2 = atags/dtb pointer
* r9 = processor ID
*/
__INIT
Expand Down
8 changes: 4 additions & 4 deletions trunk/arch/arm/kernel/head.S
Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,7 @@
*
* This is normally called from the decompressor code. The requirements
* are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
* r1 = machine nr, r2 = atags pointer.
* r1 = machine nr, r2 = atags or dtb pointer.
*
* This code is mostly position independent, so if you link the kernel at
* 0xc0008000, you call this at __pa(0xc0008000).
Expand Down Expand Up @@ -91,7 +91,7 @@ ENTRY(stext)
#endif

/*
* r1 = machine no, r2 = atags,
* r1 = machine no, r2 = atags or dtb,
* r8 = phys_offset, r9 = cpuid, r10 = procinfo
*/
bl __vet_atags
Expand Down Expand Up @@ -339,7 +339,7 @@ __secondary_data:
*
* r0 = cp#15 control register
* r1 = machine ID
* r2 = atags pointer
* r2 = atags or dtb pointer
* r4 = page table pointer
* r9 = processor ID
* r13 = *virtual* address to jump to upon completion
Expand Down Expand Up @@ -376,7 +376,7 @@ ENDPROC(__enable_mmu)
*
* r0 = cp#15 control register
* r1 = machine ID
* r2 = atags pointer
* r2 = atags or dtb pointer
* r9 = processor ID
* r13 = *virtual* address to jump to upon completion
*
Expand Down

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