From: Dave Hansen <dave.han...@linux.intel.com> This will be used in a few patches. Right now, it's not wired up to do anything useful.
Signed-off-by: Dave Hansen <dave.han...@linux.intel.com> Cc: Andy Lutomirski <l...@kernel.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Daniel Gruss <daniel.gr...@iaik.tugraz.at> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Hugh Dickins <hu...@google.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Kees Cook <keesc...@google.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Michael Schwarz <michael.schw...@iaik.tugraz.at> Cc: Moritz Lipp <moritz.l...@iaik.tugraz.at> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Richard Fellner <richard.fell...@student.tugraz.at> Cc: Thomas Gleixner <t...@linutronix.de> Cc: linux...@kvack.org Link: http://lkml.kernel.org/r/20171123003517.8eab7...@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/mm/kaiser.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 4665dd724efb..968d5b62d597 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -29,6 +29,7 @@ #include <linux/string.h> #include <linux/types.h> #include <linux/bug.h> +#include <linux/debugfs.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/mm.h> @@ -470,3 +471,50 @@ void kaiser_remove_mapping(unsigned long start, unsigned long size) */ __native_flush_tlb_global(); } + +int kaiser_enabled = 1; +static ssize_t kaiser_enabled_read_file(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + char buf[32]; + unsigned int len; + + len = sprintf(buf, "%d\n", kaiser_enabled); + return simple_read_from_buffer(user_buf, count, ppos, buf, len); +} + +static ssize_t kaiser_enabled_write_file(struct file *file, + const char __user *user_buf, size_t count, loff_t *ppos) +{ + char buf[32]; + ssize_t len; + unsigned int enable; + + len = min(count, sizeof(buf) - 1); + if (copy_from_user(buf, user_buf, len)) + return -EFAULT; + + buf[len] = '\0'; + if (kstrtoint(buf, 0, &enable)) + return -EINVAL; + + if (enable > 1) + return -EINVAL; + + WRITE_ONCE(kaiser_enabled, enable); + return count; +} + +static const struct file_operations fops_kaiser_enabled = { + .read = kaiser_enabled_read_file, + .write = kaiser_enabled_write_file, + .llseek = default_llseek, +}; + +static int __init create_kaiser_enabled(void) +{ + debugfs_create_file("kaiser-enabled", S_IRUSR | S_IWUSR, + arch_debugfs_dir, NULL, &fops_kaiser_enabled); + return 0; +} +late_initcall(create_kaiser_enabled); -- 2.14.1
