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| /*
| * EFI entry point.
| *
| * Copyright (C) 2013, 2014 Red Hat, Inc.
| * Author: Mark Salter <msalter@redhat.com>
| *
| * This program is free software; you can redistribute it and/or modify
| * it under the terms of the GNU General Public License version 2 as
| * published by the Free Software Foundation.
| *
| */
| #include <linux/linkage.h>
| #include <linux/init.h>
|
| #include <asm/assembler.h>
|
| #define EFI_LOAD_ERROR 0x8000000000000001
|
| __INIT
|
| /*
| * We arrive here from the EFI boot manager with:
| *
| * * CPU in little-endian mode
| * * MMU on with identity-mapped RAM
| * * Icache and Dcache on
| *
| * We will most likely be running from some place other than where
| * we want to be. The kernel image wants to be placed at TEXT_OFFSET
| * from start of RAM.
| */
| ENTRY(entry)
| /*
| * Create a stack frame to save FP/LR with extra space
| * for image_addr variable passed to efi_entry().
| */
| stp x29, x30, [sp, #-32]!
| mov x29, sp
|
| /*
| * Call efi_entry to do the real work.
| * x0 and x1 are already set up by firmware. Current runtime
| * address of image is calculated and passed via *image_addr.
| *
| * unsigned long efi_entry(void *handle,
| * efi_system_table_t *sys_table,
| * unsigned long *image_addr) ;
| */
| adrp x8, _text
| add x8, x8, #:lo12:_text
| add x2, sp, 16
| str x8, [x2]
| bl efi_entry
| cmn x0, #1
| b.eq efi_load_fail
|
| /*
| * efi_entry() will have copied the kernel image if necessary and we
| * return here with device tree address in x0 and the kernel entry
| * point stored at *image_addr. Save those values in registers which
| * are callee preserved.
| */
| mov x20, x0 // DTB address
| ldr x0, [sp, #16] // relocated _text address
| ldr w21, =stext_offset
| add x21, x0, x21
|
| /*
| * Calculate size of the kernel Image (same for original and copy).
| */
| adrp x1, _text
| add x1, x1, #:lo12:_text
| adrp x2, _edata
| add x2, x2, #:lo12:_edata
| sub x1, x2, x1
|
| /*
| * Flush the copied Image to the PoC, and ensure it is not shadowed by
| * stale icache entries from before relocation.
| */
| bl __flush_dcache_area
| ic ialluis
|
| /*
| * Ensure that the rest of this function (in the original Image) is
| * visible when the caches are disabled. The I-cache can't have stale
| * entries for the VA range of the current image, so no maintenance is
| * necessary.
| */
| adr x0, entry
| adr x1, entry_end
| sub x1, x1, x0
| bl __flush_dcache_area
|
| /* Turn off Dcache and MMU */
| mrs x0, CurrentEL
| cmp x0, #CurrentEL_EL2
| b.ne 1f
| mrs x0, sctlr_el2
| bic x0, x0, #1 << 0 // clear SCTLR.M
| bic x0, x0, #1 << 2 // clear SCTLR.C
| msr sctlr_el2, x0
| isb
| b 2f
| 1:
| mrs x0, sctlr_el1
| bic x0, x0, #1 << 0 // clear SCTLR.M
| bic x0, x0, #1 << 2 // clear SCTLR.C
| msr sctlr_el1, x0
| isb
| 2:
| /* Jump to kernel entry point */
| mov x0, x20
| mov x1, xzr
| mov x2, xzr
| mov x3, xzr
| br x21
|
| efi_load_fail:
| mov x0, #EFI_LOAD_ERROR
| ldp x29, x30, [sp], #32
| ret
|
| entry_end:
| ENDPROC(entry)
|
|
