lkml.org 
[lkml]   [2017]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 39/43] x86/mm/kaiser: Add debugfs file to turn KAISER on/off at runtime
    Date
    From: Dave Hansen <dave.hansen@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.hansen@linux.intel.com>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: daniel.gruss@iaik.tugraz.at
    Cc: hughd@google.com
    Cc: keescook@google.com
    Cc: linux-mm@kvack.org
    Cc: luto@kernel.org
    Cc: michael.schwarz@iaik.tugraz.at
    Cc: moritz.lipp@iaik.tugraz.at
    Cc: richard.fellner@student.tugraz.at
    Link: https://lkml.kernel.org/r/20171123003517.8EAB76E0@viggo.jf.intel.com
    Signed-off-by: Ingo Molnar <mingo@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
    \
     
     \ /
      Last update: 2017-11-24 18:28    [W:3.204 / U:0.956 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site