linux/arch/arm64/kernel/efi-entry.S
Linus Torvalds b64bb1d758 arm64 updates for 3.19
Changes include:
  - Support for alternative instruction patching from Andre
  - seccomp from Akashi
  - Some AArch32 instruction emulation, required by the Android folks
  - Optimisations for exception entry/exit code, cmpxchg, pcpu atomics
  - mmu_gather range calculations moved into core code
  - EFI updates from Ard, including long-awaited SMBIOS support
  - /proc/cpuinfo fixes to align with the format used by arch/arm/
  - A few non-critical fixes across the architecture
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "Here's the usual mixed bag of arm64 updates, also including some
  related EFI changes (Acked by Matt) and the MMU gather range cleanup
  (Acked by you).

  Changes include:
   - support for alternative instruction patching from Andre
   - seccomp from Akashi
   - some AArch32 instruction emulation, required by the Android folks
   - optimisations for exception entry/exit code, cmpxchg, pcpu atomics
   - mmu_gather range calculations moved into core code
   - EFI updates from Ard, including long-awaited SMBIOS support
   - /proc/cpuinfo fixes to align with the format used by arch/arm/
   - a few non-critical fixes across the architecture"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (70 commits)
  arm64: remove the unnecessary arm64_swiotlb_init()
  arm64: add module support for alternatives fixups
  arm64: perf: Prevent wraparound during overflow
  arm64/include/asm: Fixed a warning about 'struct pt_regs'
  arm64: Provide a namespace to NCAPS
  arm64: bpf: lift restriction on last instruction
  arm64: Implement support for read-mostly sections
  arm64: compat: align cacheflush syscall with arch/arm
  arm64: add seccomp support
  arm64: add SIGSYS siginfo for compat task
  arm64: add seccomp syscall for compat task
  asm-generic: add generic seccomp.h for secure computing mode 1
  arm64: ptrace: allow tracer to skip a system call
  arm64: ptrace: add NT_ARM_SYSTEM_CALL regset
  arm64: Move some head.text functions to executable section
  arm64: jump labels: NOP out NOP -> NOP replacement
  arm64: add support to dump the kernel page tables
  arm64: Add FIX_HOLE to permanent fixed addresses
  arm64: alternatives: fix pr_fmt string for consistency
  arm64: vmlinux.lds.S: don't discard .exit.* sections at link-time
  ...
2014-12-09 13:12:47 -08:00

125 lines
2.9 KiB
ArmAsm

/*
* 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(efi_stub_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]!
/*
* 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 x21, =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, efi_stub_entry
adr x1, efi_stub_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
efi_stub_entry_end:
ENDPROC(efi_stub_entry)