linux/arch/arm64/include/asm/dcc.h
Thomas Gleixner 97fb5e8d9b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 and
  only version 2 as published by the free software foundation this
  program is distributed in the hope that 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 294 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/20190529141900.825281744@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:36:37 +02:00

42 lines
981 B
C

/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2014-2015 The Linux Foundation. All rights reserved.
*
* A call to __dcc_getchar() or __dcc_putchar() is typically followed by
* a call to __dcc_getstatus(). We want to make sure that the CPU does
* not speculative read the DCC status before executing the read or write
* instruction. That's what the ISBs are for.
*
* The 'volatile' ensures that the compiler does not cache the status bits,
* and instead reads the DCC register every time.
*/
#ifndef __ASM_DCC_H
#define __ASM_DCC_H
#include <asm/barrier.h>
#include <asm/sysreg.h>
static inline u32 __dcc_getstatus(void)
{
return read_sysreg(mdccsr_el0);
}
static inline char __dcc_getchar(void)
{
char c = read_sysreg(dbgdtrrx_el0);
isb();
return c;
}
static inline void __dcc_putchar(char c)
{
/*
* The typecast is to make absolutely certain that 'c' is
* zero-extended.
*/
write_sysreg((unsigned char)c, dbgdtrtx_el0);
isb();
}
#endif