*
*/
+#define ATAG_CORE 0x54410001
+#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
+
.type __switch_data, %object
__switch_data:
.long __mmap_switched
.long _end @ r7
.long processor_id @ r4
.long __machine_arch_type @ r5
- .long cr_alignment @ r6
+ .long __atags_pointer @ r6
+ .long cr_alignment @ r7
.long init_thread_union + THREAD_START_SP @ sp
/*
*
* r0 = cp#15 control register
* r1 = machine ID
+ * r2 = atags pointer
* r9 = processor ID
*/
.type __mmap_switched, %function
strcc fp, [r6],#4
bcc 1b
- ldmia r3, {r4, r5, r6, sp}
+ ldmia r3, {r4, r5, r6, r7, sp}
str r9, [r4] @ Save processor ID
str r1, [r5] @ Save machine type
+ str r2, [r6] @ Save atags pointer
bic r4, r0, #CR_A @ Clear 'A' bit
- stmia r6, {r0, r4} @ Save control register values
+ stmia r7, {r0, r4} @ Save control register values
b start_kernel
/*
#ifdef CONFIG_DEBUG_LL
adr r0, str_p1
bl printascii
+ mov r0, r9
+ bl printhex8
+ adr r0, str_p2
+ bl printascii
b __error
-str_p1: .asciz "\nError: unrecognized/unsupported processor variant.\n"
+str_p1: .asciz "\nError: unrecognized/unsupported processor variant (0x"
+str_p2: .asciz ").\n"
.align
#endif
bl __lookup_machine_type
mov r0, r5
ldmfd sp!, {r4 - r6, pc}
+
+/* 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
+ * of this function may be more lenient with the physical address and
+ * may also be able to move the ATAGS block if necessary.
+ *
+ * r8 = machinfo
+ *
+ * Returns:
+ * r2 either valid atags pointer, or zero
+ * r5, r6 corrupted
+ */
+
+ .type __vet_atags, %function
+__vet_atags:
+ tst r2, #0x3 @ aligned?
+ bne 1f
+
+ ldr r5, [r2, #0] @ is first tag ATAG_CORE?
+ subs r5, r5, #ATAG_CORE_SIZE
+ bne 1f
+ ldr r5, [r2, #4]
+ ldr r6, =ATAG_CORE
+ cmp r5, r6
+ bne 1f
+
+ mov pc, lr @ atag pointer is ok
+
+1: mov r2, #0
+ mov pc, lr