UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

x86/mm/init32: Mark text and rodata RO in one go 

The sequence of marking text and rodata read-only in 32bit init is:

  set_ro(text);
  kernel_set_to_readonly = 1;
  set_ro(rodata);

When kernel_set_to_readonly is 1 it enables the protection mechanism in CPA
for the read only regions. With the upcoming checks for existing mappings
this consequently triggers the warning about an existing mapping being
incorrect vs. static protections because rodata has not been converted yet.

There is no technical reason to split the two, so just combine the RO
protection to convert text and rodata in one go.

Convert the printks to pr_info while at it.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143545.731701535@linutronix.de
This commit is contained in:
Thomas Gleixner 2018-09-17 16:29:07 +02:00
parent 6bf4ca7fbc
commit 2a25dc7c79
1 changed files with 4 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
arch/x86/mm/init_32.c
View File

@ -923,34 +923,19 @@ static void mark_nxdata_nx(void)
void mark_rodata_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
unsigned long size = (unsigned long)__end_rodata - start;
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
printk(KERN_INFO "Write protecting the kernel text: %luk\n",
pr_info("Write protecting kernel text and read-only data: %luk\n",
size >> 10);
kernel_set_to_readonly = 1;
#ifdef CONFIG_CPA_DEBUG
printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
start, start+size);
set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
printk(KERN_INFO "Testing CPA: write protecting again\n");
set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
#endif
start += size;
size = (unsigned long)__end_rodata - start;
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
size >> 10);
#ifdef CONFIG_CPA_DEBUG
printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size);
set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
printk(KERN_INFO "Testing CPA: write protecting again\n");
pr_info("Testing CPA: write protecting again\n");
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
#endif
mark_nxdata_nx();