diff mbox series

[v15,06/26] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW

Message ID 20201110162211.9207-7-yu-cheng.yu@intel.com (mailing list archive)
State New, archived
Headers show
Series Control-flow Enforcement: Shadow Stack | expand

Commit Message

Yu-cheng Yu Nov. 10, 2020, 4:21 p.m. UTC 
Before introducing _PAGE_COW for non-hardware memory management purposes in
the next patch, rename _PAGE_DIRTY to _PAGE_DIRTY_HW and _PAGE_BIT_DIRTY to
_PAGE_BIT_DIRTY_HW to make meanings more clear.  There are no functional
changes from this patch.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
---
 arch/x86/include/asm/pgtable.h       | 18 +++++++++---------
 arch/x86/include/asm/pgtable_types.h | 10 +++++-----
 arch/x86/kernel/relocate_kernel_64.S |  2 +-
 arch/x86/kvm/vmx/vmx.c               |  2 +-
 4 files changed, 16 insertions(+), 16 deletions(-)

Comments

Borislav Petkov Dec. 3, 2020, 9:19 a.m. UTC | #1 
On Tue, Nov 10, 2020 at 08:21:51AM -0800, Yu-cheng Yu wrote:
> Before introducing _PAGE_COW for non-hardware memory management purposes in
> the next patch, rename _PAGE_DIRTY to _PAGE_DIRTY_HW and _PAGE_BIT_DIRTY to
> _PAGE_BIT_DIRTY_HW to make meanings more clear.  There are no functional
> changes from this patch.

There's no guarantee for "next" or "this" patch when a patch gets
applied so reword your commit message pls.

Also, I fail to understand here what _PAGE_DIRTY_HW makes more clear?
The page dirty bit is clear enough to me so why the churn?

Thx.
Dave Hansen Dec. 3, 2020, 3:12 p.m. UTC | #2 
On 12/3/20 1:19 AM, Borislav Petkov wrote:
> On Tue, Nov 10, 2020 at 08:21:51AM -0800, Yu-cheng Yu wrote:
>> Before introducing _PAGE_COW for non-hardware memory management purposes in
>> the next patch, rename _PAGE_DIRTY to _PAGE_DIRTY_HW and _PAGE_BIT_DIRTY to
>> _PAGE_BIT_DIRTY_HW to make meanings more clear.  There are no functional
>> changes from this patch.
> There's no guarantee for "next" or "this" patch when a patch gets
> applied so reword your commit message pls.
> 
> Also, I fail to understand here what _PAGE_DIRTY_HW makes more clear?
> The page dirty bit is clear enough to me so why the churn?

Once upon a time in this set, we had:

	_PAGE_DIRTY	(the old hardware bit)
and
	_PAGE_DIRTY_SW	(the new shadow stack necessitated bit)

In *that* case, it made sense to change the name of the hardware one to
help differentiate them.  But, over time, we changed _PAGE_DIRTY_SW to
_PAGE_COW.

I think you're right.  The renaming is just churn now with the current
naming.
Yu-cheng Yu Dec. 3, 2020, 3:56 p.m. UTC | #3 
On 12/3/2020 7:12 AM, Dave Hansen wrote:
> On 12/3/20 1:19 AM, Borislav Petkov wrote:
>> On Tue, Nov 10, 2020 at 08:21:51AM -0800, Yu-cheng Yu wrote:
>>> Before introducing _PAGE_COW for non-hardware memory management purposes in
>>> the next patch, rename _PAGE_DIRTY to _PAGE_DIRTY_HW and _PAGE_BIT_DIRTY to
>>> _PAGE_BIT_DIRTY_HW to make meanings more clear.  There are no functional
>>> changes from this patch.
>> There's no guarantee for "next" or "this" patch when a patch gets
>> applied so reword your commit message pls.
>>
>> Also, I fail to understand here what _PAGE_DIRTY_HW makes more clear?
>> The page dirty bit is clear enough to me so why the churn?
> 
> Once upon a time in this set, we had:
> 
> 	_PAGE_DIRTY	(the old hardware bit)
> and
> 	_PAGE_DIRTY_SW	(the new shadow stack necessitated bit)
> 
> In *that* case, it made sense to change the name of the hardware one to
> help differentiate them.  But, over time, we changed _PAGE_DIRTY_SW to
> _PAGE_COW.
> 
> I think you're right.  The renaming is just churn now with the current
> naming.
> 

Ok, I will drop this patch.
diff mbox series

Patch

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index a02c67291cfc..b23697658b28 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -123,7 +123,7 @@  extern pmdval_t early_pmd_flags;
  */
 static inline int pte_dirty(pte_t pte)
 {
-	return pte_flags(pte) & _PAGE_DIRTY;
+	return pte_flags(pte) & _PAGE_DIRTY_HW;
 }
 
 
@@ -162,7 +162,7 @@  static inline int pte_young(pte_t pte)
 
 static inline int pmd_dirty(pmd_t pmd)
 {
-	return pmd_flags(pmd) & _PAGE_DIRTY;
+	return pmd_flags(pmd) & _PAGE_DIRTY_HW;
 }
 
 static inline int pmd_young(pmd_t pmd)
@@ -172,7 +172,7 @@  static inline int pmd_young(pmd_t pmd)
 
 static inline int pud_dirty(pud_t pud)
 {
-	return pud_flags(pud) & _PAGE_DIRTY;
+	return pud_flags(pud) & _PAGE_DIRTY_HW;
 }
 
 static inline int pud_young(pud_t pud)
@@ -333,7 +333,7 @@  static inline pte_t pte_clear_uffd_wp(pte_t pte)
 
 static inline pte_t pte_mkclean(pte_t pte)
 {
-	return pte_clear_flags(pte, _PAGE_DIRTY);
+	return pte_clear_flags(pte, _PAGE_DIRTY_HW);
 }
 
 static inline pte_t pte_mkold(pte_t pte)
@@ -353,7 +353,7 @@  static inline pte_t pte_mkexec(pte_t pte)
 
 static inline pte_t pte_mkdirty(pte_t pte)
 {
-	return pte_set_flags(pte, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+	return pte_set_flags(pte, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
 }
 
 static inline pte_t pte_mkyoung(pte_t pte)
@@ -434,7 +434,7 @@  static inline pmd_t pmd_mkold(pmd_t pmd)
 
 static inline pmd_t pmd_mkclean(pmd_t pmd)
 {
-	return pmd_clear_flags(pmd, _PAGE_DIRTY);
+	return pmd_clear_flags(pmd, _PAGE_DIRTY_HW);
 }
 
 static inline pmd_t pmd_wrprotect(pmd_t pmd)
@@ -444,7 +444,7 @@  static inline pmd_t pmd_wrprotect(pmd_t pmd)
 
 static inline pmd_t pmd_mkdirty(pmd_t pmd)
 {
-	return pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+	return pmd_set_flags(pmd, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
 }
 
 static inline pmd_t pmd_mkdevmap(pmd_t pmd)
@@ -488,7 +488,7 @@  static inline pud_t pud_mkold(pud_t pud)
 
 static inline pud_t pud_mkclean(pud_t pud)
 {
-	return pud_clear_flags(pud, _PAGE_DIRTY);
+	return pud_clear_flags(pud, _PAGE_DIRTY_HW);
 }
 
 static inline pud_t pud_wrprotect(pud_t pud)
@@ -498,7 +498,7 @@  static inline pud_t pud_wrprotect(pud_t pud)
 
 static inline pud_t pud_mkdirty(pud_t pud)
 {
-	return pud_set_flags(pud, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+	return pud_set_flags(pud, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
 }
 
 static inline pud_t pud_mkdevmap(pud_t pud)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 816b31c68550..810eb1567050 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -15,7 +15,7 @@ 
 #define _PAGE_BIT_PWT		3	/* page write through */
 #define _PAGE_BIT_PCD		4	/* page cache disabled */
 #define _PAGE_BIT_ACCESSED	5	/* was accessed (raised by CPU) */
-#define _PAGE_BIT_DIRTY		6	/* was written to (raised by CPU) */
+#define _PAGE_BIT_DIRTY_HW	6	/* was written to (raised by CPU) */
 #define _PAGE_BIT_PSE		7	/* 4 MB (or 2MB) page */
 #define _PAGE_BIT_PAT		7	/* on 4KB pages */
 #define _PAGE_BIT_GLOBAL	8	/* Global TLB entry PPro+ */
@@ -46,7 +46,7 @@ 
 #define _PAGE_PWT	(_AT(pteval_t, 1) << _PAGE_BIT_PWT)
 #define _PAGE_PCD	(_AT(pteval_t, 1) << _PAGE_BIT_PCD)
 #define _PAGE_ACCESSED	(_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
-#define _PAGE_DIRTY	(_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
+#define _PAGE_DIRTY_HW	(_AT(pteval_t, 1) << _PAGE_BIT_DIRTY_HW)
 #define _PAGE_PSE	(_AT(pteval_t, 1) << _PAGE_BIT_PSE)
 #define _PAGE_GLOBAL	(_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
 #define _PAGE_SOFTW1	(_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1)
@@ -74,7 +74,7 @@ 
 			 _PAGE_PKEY_BIT3)
 
 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
-#define _PAGE_KNL_ERRATUM_MASK (_PAGE_DIRTY | _PAGE_ACCESSED)
+#define _PAGE_KNL_ERRATUM_MASK (_PAGE_DIRTY_HW | _PAGE_ACCESSED)
 #else
 #define _PAGE_KNL_ERRATUM_MASK 0
 #endif
@@ -126,7 +126,7 @@ 
  * pte_modify() does modify it.
  */
 #define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
-			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY |	\
+			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY_HW |	\
 			 _PAGE_SOFT_DIRTY | _PAGE_DEVMAP | _PAGE_ENC |  \
 			 _PAGE_UFFD_WP)
 #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
@@ -163,7 +163,7 @@  enum page_cache_mode {
 #define __RW _PAGE_RW
 #define _USR _PAGE_USER
 #define ___A _PAGE_ACCESSED
-#define ___D _PAGE_DIRTY
+#define ___D _PAGE_DIRTY_HW
 #define ___G _PAGE_GLOBAL
 #define __NX _PAGE_NX
 
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index a4d9a261425b..e3bb4ff95523 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -17,7 +17,7 @@ 
  */
 
 #define PTR(x) (x << 3)
-#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
+#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY_HW)
 
 /*
  * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 47b8357b9751..3962284843ee 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3574,7 +3574,7 @@  static int init_rmode_identity_map(struct kvm *kvm)
 	/* Set up identity-mapping pagetable for EPT in real mode */
 	for (i = 0; i < PT32_ENT_PER_PAGE; i++) {
 		tmp = (i << 22) + (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |
-			_PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE);
+			_PAGE_ACCESSED | _PAGE_DIRTY_HW | _PAGE_PSE);
 		r = kvm_write_guest_page(kvm, identity_map_pfn,
 				&tmp, i * sizeof(tmp), sizeof(tmp));
 		if (r < 0)