lkml.org 
[lkml]   [2017]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 1/4] x86/kaiser: Simplify disabling of global pages
The current way of disabling global pages at compile time prevents boot
time disabling of kaiser and creates unnecessary indirections.

Global pages can be supressed by __supported_pte_mask as well. The shadow
mappings set PAGE_GLOBAL for the minimal kernel mappings which are required
for entry/exit. These mappings are setup manually so the filtering does not
take place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/pgtable_types.h | 16 +---------------
arch/x86/mm/init.c | 13 ++++++++++---
arch/x86/mm/pageattr.c | 16 ++++++++--------
3 files changed, 19 insertions(+), 26 deletions(-)

--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -191,23 +191,9 @@ enum page_cache_mode {
#define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | \
_PAGE_ACCESSED)

-/*
- * Disable global pages for anything using the default
- * __PAGE_KERNEL* macros.
- *
- * PGE will still be enabled and _PAGE_GLOBAL may still be used carefully
- * for a few selected kernel mappings which must be visible to userspace,
- * when KAISER is enabled, like the entry/exit code and data.
- */
-#ifdef CONFIG_KAISER
-#define __PAGE_KERNEL_GLOBAL 0
-#else
-#define __PAGE_KERNEL_GLOBAL _PAGE_GLOBAL
-#endif
-
#define __PAGE_KERNEL_EXEC \
(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | \
- __PAGE_KERNEL_GLOBAL)
+ _PAGE_GLOBAL)
#define __PAGE_KERNEL (__PAGE_KERNEL_EXEC | _PAGE_NX)

#define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -161,6 +161,13 @@ struct map_range {

static int page_size_mask;

+static void enable_global_pages(void)
+{
+#ifndef CONFIG_KAISER
+ __supported_pte_mask |= _PAGE_GLOBAL;
+#endif
+}
+
static void __init probe_page_size_mask(void)
{
/*
@@ -179,11 +186,11 @@ static void __init probe_page_size_mask(
cr4_set_bits_and_update_boot(X86_CR4_PSE);

/* Enable PGE if available */
+ __supported_pte_mask &= ~_PAGE_GLOBAL;
if (boot_cpu_has(X86_FEATURE_PGE)) {
cr4_set_bits_and_update_boot(X86_CR4_PGE);
- __supported_pte_mask |= _PAGE_GLOBAL;
- } else
- __supported_pte_mask &= ~_PAGE_GLOBAL;
+ enable_global_pages();
+ }

/* Enable 1 GB linear kernel mappings if available: */
if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -585,9 +585,9 @@ try_preserve_large_page(pte_t *kpte, uns
* for the ancient hardware that doesn't support it.
*/
if (pgprot_val(req_prot) & _PAGE_PRESENT)
- pgprot_val(req_prot) |= _PAGE_PSE | __PAGE_KERNEL_GLOBAL;
+ pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL;
else
- pgprot_val(req_prot) &= ~(_PAGE_PSE | __PAGE_KERNEL_GLOBAL);
+ pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL);

req_prot = canon_pgprot(req_prot);

@@ -705,9 +705,9 @@ static int
* for the ancient hardware that doesn't support it.
*/
if (pgprot_val(ref_prot) & _PAGE_PRESENT)
- pgprot_val(ref_prot) |= __PAGE_KERNEL_GLOBAL;
+ pgprot_val(ref_prot) |= _PAGE_GLOBAL;
else
- pgprot_val(ref_prot) &= ~__PAGE_KERNEL_GLOBAL;
+ pgprot_val(ref_prot) &= ~_PAGE_GLOBAL;

/*
* Get the target pfn from the original entry:
@@ -938,9 +938,9 @@ static void populate_pte(struct cpa_data
* support it.
*/
if (pgprot_val(pgprot) & _PAGE_PRESENT)
- pgprot_val(pgprot) |= __PAGE_KERNEL_GLOBAL;
+ pgprot_val(pgprot) |= _PAGE_GLOBAL;
else
- pgprot_val(pgprot) &= ~__PAGE_KERNEL_GLOBAL;
+ pgprot_val(pgprot) &= ~_PAGE_GLOBAL;

pgprot = canon_pgprot(pgprot);

@@ -1242,9 +1242,9 @@ static int __change_page_attr(struct cpa
* support it.
*/
if (pgprot_val(new_prot) & _PAGE_PRESENT)
- pgprot_val(new_prot) |= __PAGE_KERNEL_GLOBAL;
+ pgprot_val(new_prot) |= _PAGE_GLOBAL;
else
- pgprot_val(new_prot) &= ~__PAGE_KERNEL_GLOBAL;
+ pgprot_val(new_prot) &= ~_PAGE_GLOBAL;

/*
* We need to keep the pfn from the existing PTE,

\
 
 \ /
  Last update: 2017-11-26 19:10    [W:0.038 / U:0.420 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site