/*
|
* 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) ;
|
*/
|
adr_l x8, _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).
|
*/
|
adr_l x1, _text
|
adr_l x2, _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
|
pre_disable_mmu_workaround
|
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
|
pre_disable_mmu_workaround
|
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)
|
