[ARM] 4423/1: add ATAGS support (9d20fdd5) · Commits · 戴 / test

arch/arm/kernel/head-common.S

+37 −3

Original line number	Diff line number	Diff line
		@@ -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

arch/arm/kernel/head.S

+6 −1

Original line number	Diff line number	Diff line
		@@ -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 ((24 + 34) >> 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

		/*

arch/arm/kernel/setup.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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);

		/*

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