mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 18:14:07 +08:00
372fddf709
This kernel parameter allows to force kernel to use 4-level paging even if hardware and kernel support 5-level paging. The option may be useful to work around regressions related to 5-level paging. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Hugh Dickins <hughd@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180518103528.59260-5-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
35 lines
826 B
C
35 lines
826 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include "misc.h"
|
|
|
|
#if CONFIG_EARLY_PRINTK || CONFIG_RANDOMIZE_BASE || CONFIG_X86_5LEVEL
|
|
|
|
static unsigned long fs;
|
|
static inline void set_fs(unsigned long seg)
|
|
{
|
|
fs = seg << 4; /* shift it back */
|
|
}
|
|
typedef unsigned long addr_t;
|
|
static inline char rdfs8(addr_t addr)
|
|
{
|
|
return *((char *)(fs + addr));
|
|
}
|
|
#include "../cmdline.c"
|
|
unsigned long get_cmd_line_ptr(void)
|
|
{
|
|
unsigned long cmd_line_ptr = boot_params->hdr.cmd_line_ptr;
|
|
|
|
cmd_line_ptr |= (u64)boot_params->ext_cmd_line_ptr << 32;
|
|
|
|
return cmd_line_ptr;
|
|
}
|
|
int cmdline_find_option(const char *option, char *buffer, int bufsize)
|
|
{
|
|
return __cmdline_find_option(get_cmd_line_ptr(), option, buffer, bufsize);
|
|
}
|
|
int cmdline_find_option_bool(const char *option)
|
|
{
|
|
return __cmdline_find_option_bool(get_cmd_line_ptr(), option);
|
|
}
|
|
|
|
#endif
|