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Commit 22dae6cb authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Sami Tolvanen
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UPSTREAM: arm64: remove __calc_phys_offset 



This removes the function __calc_phys_offset and all open coded
virtual to physical address translations using the offset kept
in x28.

Instead, just use absolute or PC-relative symbol references as
appropriate when referring to virtual or physical addresses,
respectively.

Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>

Bug: 31432001
Change-Id: I2b838e4c9f0a35960a055ccc31123de80929ecc1
(cherry picked from commit 6f4d57fa7021efbf135cfa068d56bc5035edffa1)
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
parent cb6afcca

arch/arm64/kernel/head.S

+11 −36
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ 
#include <asm/page.h>

#include <asm/virt.h>



#define KERNEL_RAM_VADDR	(PAGE_OFFSET + TEXT_OFFSET)

#define __PHYS_OFFSET	(KERNEL_START - TEXT_OFFSET)



#if (TEXT_OFFSET & 0xfff) != 0

#error TEXT_OFFSET must be at least 4KB aligned
@@ -46,13 +46,6 @@ 
#error TEXT_OFFSET must be less than 2MB

#endif



	.macro	pgtbl, ttb0, ttb1, virt_to_phys

	ldr	\ttb1, =swapper_pg_dir

	ldr	\ttb0, =idmap_pg_dir

	add	\ttb1, \ttb1, \virt_to_phys

	add	\ttb0, \ttb0, \virt_to_phys

	.endm



#ifdef CONFIG_ARM64_64K_PAGES

#define BLOCK_SHIFT	PAGE_SHIFT

#define BLOCK_SIZE	PAGE_SIZE
@@ -63,7 +56,7 @@ 
#define TABLE_SHIFT	PUD_SHIFT

#endif



#define KERNEL_START	KERNEL_RAM_VADDR

#define KERNEL_START	_text

#define KERNEL_END	_end



/*
@@ -237,7 +230,7 @@ section_table: 
ENTRY(stext)

	mov	x21, x0				// x21=FDT

	bl	el2_setup			// Drop to EL1, w20=cpu_boot_mode

	bl	__calc_phys_offset		// x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET

	adrp	x24, __PHYS_OFFSET

	bl	set_cpu_boot_mode_flag



	bl	__vet_fdt
@@ -337,7 +330,8 @@ ENDPROC(__vet_fdt) 
 *   - pgd entry for fixed mappings (TTBR1)

 */

__create_page_tables:

	pgtbl	x25, x26, x28			// idmap_pg_dir and swapper_pg_dir addresses

	adrp	x25, idmap_pg_dir

	adrp	x26, swapper_pg_dir

	mov	x27, lr



	/*
@@ -366,12 +360,10 @@ __create_page_tables: 
	 * Create the identity mapping.

	 */

	mov	x0, x25				// idmap_pg_dir

	ldr	x3, =KERNEL_START

	add	x3, x3, x28			// __pa(KERNEL_START)

	adrp	x3, KERNEL_START		// __pa(KERNEL_START)

	create_pgd_entry x0, x3, x5, x6

	ldr	x6, =KERNEL_END

	mov	x5, x3				// __pa(KERNEL_START)

	add	x6, x6, x28			// __pa(KERNEL_END)

	adr_l	x6, KERNEL_END			// __pa(KERNEL_END)

	create_block_map x0, x7, x3, x5, x6



	/*
@@ -380,7 +372,7 @@ __create_page_tables: 
	mov	x0, x26				// swapper_pg_dir

	mov	x5, #PAGE_OFFSET

	create_pgd_entry x0, x5, x3, x6

	ldr	x6, =KERNEL_END

	ldr	x6, =KERNEL_END			// __va(KERNEL_END)

	mov	x3, x24				// phys offset

	create_block_map x0, x7, x3, x5, x6
@@ -532,8 +524,7 @@ ENDPROC(el2_setup) 
 * in x20. See arch/arm64/include/asm/virt.h for more info.

 */

ENTRY(set_cpu_boot_mode_flag)

	ldr	x1, =__boot_cpu_mode		// Compute __boot_cpu_mode

	add	x1, x1, x28

	adr_l	x1, __boot_cpu_mode

	cmp	w20, #BOOT_CPU_MODE_EL2

	b.ne	1f

	add	x1, x1, #4
@@ -567,7 +558,6 @@ ENTRY(__boot_cpu_mode) 
	 */

ENTRY(secondary_holding_pen)

	bl	el2_setup			// Drop to EL1, w20=cpu_boot_mode

	bl	__calc_phys_offset		// x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET

	bl	set_cpu_boot_mode_flag

	mrs	x0, mpidr_el1

	ldr     x1, =MPIDR_HWID_BITMASK
@@ -586,7 +576,6 @@ ENDPROC(secondary_holding_pen) 
	 */

ENTRY(secondary_entry)

	bl	el2_setup			// Drop to EL1

	bl	__calc_phys_offset		// x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET

	bl	set_cpu_boot_mode_flag

	b	secondary_startup

ENDPROC(secondary_entry)
@@ -595,7 +584,8 @@ ENTRY(secondary_startup) 
	/*

	 * Common entry point for secondary CPUs.

	 */

	pgtbl	x25, x26, x28			// x25=TTBR0, x26=TTBR1

	adrp	x25, idmap_pg_dir

	adrp	x26, swapper_pg_dir

	bl	__cpu_setup			// initialise processor



	ldr	x21, =secondary_data
@@ -636,18 +626,3 @@ __enable_mmu: 
	isb

	br	x27

ENDPROC(__enable_mmu)
 


/*

 * Calculate the start of physical memory.

 */

__calc_phys_offset:

	adr	x0, 1f

	ldp	x1, x2, [x0]

	sub	x28, x0, x1			// x28 = PHYS_OFFSET - PAGE_OFFSET

	add	x24, x2, x28			// x24 = PHYS_OFFSET

	ret

ENDPROC(__calc_phys_offset)



	.align 3

1:	.quad	.

	.quad	PAGE_OFFSET