mirror of
https://github.com/torvalds/linux.git
synced 2024-12-13 22:53:20 +00:00
2025cf9e19
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 263 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
60 lines
877 B
ArmAsm
60 lines
877 B
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* thunks.S - assembly helpers for mixed-bitness code
|
|
* Copyright (c) 2015 Andrew Lutomirski
|
|
*
|
|
* These are little helpers that make it easier to switch bitness on
|
|
* the fly.
|
|
*/
|
|
|
|
.text
|
|
|
|
.global call32_from_64
|
|
.type call32_from_64, @function
|
|
call32_from_64:
|
|
// rdi: stack to use
|
|
// esi: function to call
|
|
|
|
// Save registers
|
|
pushq %rbx
|
|
pushq %rbp
|
|
pushq %r12
|
|
pushq %r13
|
|
pushq %r14
|
|
pushq %r15
|
|
pushfq
|
|
|
|
// Switch stacks
|
|
mov %rsp,(%rdi)
|
|
mov %rdi,%rsp
|
|
|
|
// Switch to compatibility mode
|
|
pushq $0x23 /* USER32_CS */
|
|
pushq $1f
|
|
lretq
|
|
|
|
1:
|
|
.code32
|
|
// Call the function
|
|
call *%esi
|
|
// Switch back to long mode
|
|
jmp $0x33,$1f
|
|
.code64
|
|
|
|
1:
|
|
// Restore the stack
|
|
mov (%rsp),%rsp
|
|
|
|
// Restore registers
|
|
popfq
|
|
popq %r15
|
|
popq %r14
|
|
popq %r13
|
|
popq %r12
|
|
popq %rbp
|
|
popq %rbx
|
|
|
|
ret
|
|
|
|
.size call32_from_64, .-call32_from_64
|