From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/arm64/include/asm/dcc.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 arch/arm64/include/asm/dcc.h (limited to 'arch/arm64/include/asm/dcc.h') diff --git a/arch/arm64/include/asm/dcc.h b/arch/arm64/include/asm/dcc.h new file mode 100644 index 0000000000..ebd9fb4720 --- /dev/null +++ b/arch/arm64/include/asm/dcc.h @@ -0,0 +1,41 @@ +/* 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 +#include + +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 -- cgit v1.2.3