From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/arm/kernel/thumbee.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 arch/arm/kernel/thumbee.c (limited to 'arch/arm/kernel/thumbee.c') diff --git a/arch/arm/kernel/thumbee.c b/arch/arm/kernel/thumbee.c new file mode 100644 index 000000000..d832eb9e6 --- /dev/null +++ b/arch/arm/kernel/thumbee.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * arch/arm/kernel/thumbee.c + * + * Copyright (C) 2008 ARM Limited + */ + +#include +#include + +#include +#include +#include + +/* + * Access to the ThumbEE Handler Base register + */ +static inline unsigned long teehbr_read(void) +{ + unsigned long v; + asm("mrc p14, 6, %0, c1, c0, 0\n" : "=r" (v)); + return v; +} + +static inline void teehbr_write(unsigned long v) +{ + asm("mcr p14, 6, %0, c1, c0, 0\n" : : "r" (v)); +} + +static int thumbee_notifier(struct notifier_block *self, unsigned long cmd, void *t) +{ + struct thread_info *thread = t; + + switch (cmd) { + case THREAD_NOTIFY_FLUSH: + teehbr_write(0); + break; + case THREAD_NOTIFY_SWITCH: + current_thread_info()->thumbee_state = teehbr_read(); + teehbr_write(thread->thumbee_state); + break; + } + + return NOTIFY_DONE; +} + +static struct notifier_block thumbee_notifier_block = { + .notifier_call = thumbee_notifier, +}; + +static int __init thumbee_init(void) +{ + unsigned long pfr0; + unsigned int cpu_arch = cpu_architecture(); + + if (cpu_arch < CPU_ARCH_ARMv7) + return 0; + + pfr0 = read_cpuid_ext(CPUID_EXT_PFR0); + if ((pfr0 & 0x0000f000) != 0x00001000) + return 0; + + pr_info("ThumbEE CPU extension supported.\n"); + elf_hwcap |= HWCAP_THUMBEE; + thread_register_notifier(&thumbee_notifier_block); + + return 0; +} + +late_initcall(thumbee_init); -- cgit v1.2.3