diff options
| -rw-r--r-- | arch/arm/kernel/head-common.S | 40 | ||||
| -rw-r--r-- | arch/arm/kernel/head.S | 7 | ||||
| -rw-r--r-- | arch/arm/kernel/setup.c | 6 |
3 files changed, 48 insertions, 5 deletions
diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S index a52da0ddb43..024a9cf469b 100644 --- a/arch/arm/kernel/head-common.S +++ b/arch/arm/kernel/head-common.S @@ -20,7 +20,8 @@ __switch_data: .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 /* @@ -29,6 +30,7 @@ __switch_data: * * r0 = cp#15 control register * r1 = machine ID + * r2 = atags pointer * r9 = processor ID */ .type __mmap_switched, %function @@ -47,11 +49,12 @@ __mmap_switched: 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 /* @@ -215,3 +218,34 @@ ENTRY(lookup_machine_type) 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 diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 41f98b4ba2e..7898cbc9861 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -29,6 +29,10 @@ #define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET) #define KERNEL_RAM_PADDR (PHYS_OFFSET + TEXT_OFFSET) +#define ATAG_CORE 0x54410001 +#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2) + + /* * swapper_pg_dir is the virtual address of the initial page table. * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must @@ -61,7 +65,7 @@ * * 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. + * r1 = machine nr, r2 = atags pointer. * * This code is mostly position independent, so if you link the kernel at * 0xc0008000, you call this at __pa(0xc0008000). @@ -85,6 +89,7 @@ ENTRY(stext) bl __lookup_machine_type @ r5=machinfo movs r8, r5 @ invalid machine (r5=0)? beq __error_a @ yes, error 'a' + bl __vet_atags bl __create_page_tables /* diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 650eac1bc0a..5be2e987b84 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -63,6 +63,8 @@ unsigned int processor_id; unsigned int __machine_arch_type; EXPORT_SYMBOL(__machine_arch_type); +unsigned int __atags_pointer __initdata; + unsigned int system_rev; EXPORT_SYMBOL(system_rev); @@ -780,7 +782,9 @@ void __init setup_arch(char **cmdline_p) if (mdesc->soft_reboot) reboot_setup("s"); - if (mdesc->boot_params) + if (__atags_pointer) + tags = phys_to_virt(__atags_pointer); + else if (mdesc->boot_params) tags = phys_to_virt(mdesc->boot_params); /* |