linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v3 0/3] x86/mm/64: Remove vmalloc/ioremap pgtable synchronization
@ 2020-07-21  9:59 Joerg Roedel
  2020-07-21  9:59 ` [PATCH v3 1/3] x86/mm: Pre-allocate p4d/pud pages for vmalloc area Joerg Roedel
                   ` (4 more replies)
  0 siblings, 5 replies; 11+ messages in thread
From: Joerg Roedel @ 2020-07-21  9:59 UTC (permalink / raw)
  To: x86
  Cc: hpa, Dave Hansen, Andy Lutomirski, Peter Zijlstra, Andrew Morton,
	Mike Rapoport, Joerg Roedel, joro, linux-kernel

From: Joerg Roedel <jroedel@suse.de>

Hi,

here is the third version of the patches to pre-allocate P4D/PUD pages
for the vmalloc/ioremap areas on x86-64. This makes the page-table
synchronization code obsolete and so it is also removed.

Please review.

Thanks,

	Joerg

Changes to v2:

	- Rebased to tip/master
	- Some rewording of the commit-messages 

Joerg Roedel (3):
  x86/mm: Pre-allocate p4d/pud pages for vmalloc area
  x86/mm/64: Do not sync vmalloc/ioremap mappings
  x86/mm/64: Make sync_global_pgds() static

 arch/x86/include/asm/pgtable_64.h       |  2 -
 arch/x86/include/asm/pgtable_64_types.h |  2 -
 arch/x86/mm/init_64.c                   | 59 ++++++++++++++++++++++---
 3 files changed, 53 insertions(+), 10 deletions(-)

-- 
2.27.0


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [PATCH 1/2] x86/mm/64: Do not sync vmalloc/ioremap mappings
@ 2020-08-14 15:19 Joerg Roedel
  2020-08-15 15:46 ` [tip: x86/mm] " tip-bot2 for Joerg Roedel
  0 siblings, 1 reply; 11+ messages in thread
From: Joerg Roedel @ 2020-08-14 15:19 UTC (permalink / raw)
  To: x86
  Cc: Ingo Molnar, Mike Rapoport, Dave Hansen, Andy Lutomirski,
	Peter Zijlstra, hpa, Linus Torvalds, Jason, Andrew Morton,
	linux-kernel, kirill.shutemov, Joerg Roedel

From: Joerg Roedel <jroedel@suse.de>

Remove the code to sync the vmalloc and ioremap ranges for x86-64. The
page-table pages are all pre-allocated so that synchronization is
no longer necessary.

This is a patch that already went into the kernel as:

	commit 8bb9bf242d1f ("x86/mm/64: Do not sync vmalloc/ioremap mappings")

But it had to be reverted later because it unveiled a bug from:

	commit 6eb82f994026 ("x86/mm: Pre-allocate P4D/PUD pages for vmalloc area")

The bug in that commit causes the P4D/PUD pages not to be correctly
allocated, making the synchronization still necessary. That issue got
fixed meanwhile upstream:

	commit 995909a4e22b ("x86/mm/64: Do not dereference non-present PGD entries")

With that fix it is safe again to remove the page-table synchronization
for vmalloc/ioremap ranges on x86-64.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/include/asm/pgtable_64_types.h | 2 --
 arch/x86/mm/init_64.c                   | 5 -----
 2 files changed, 7 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 8f63efb2a2cc..52e5f5f2240d 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -159,6 +159,4 @@ extern unsigned int ptrs_per_p4d;
 
 #define PGD_KERNEL_START	((PAGE_SIZE / 2) / sizeof(pgd_t))
 
-#define ARCH_PAGE_TABLE_SYNC_MASK	(pgtable_l5_enabled() ?	PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
-
 #endif /* _ASM_X86_PGTABLE_64_DEFS_H */
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a4ac13cc3fdc..777d83546764 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -217,11 +217,6 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
 		sync_global_pgds_l4(start, end);
 }
 
-void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
-{
-	sync_global_pgds(start, end);
-}
-
 /*
  * NOTE: This function is marked __ref because it calls __init function
  * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
-- 
2.28.0


^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2020-08-15 21:59 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-21  9:59 [PATCH v3 0/3] x86/mm/64: Remove vmalloc/ioremap pgtable synchronization Joerg Roedel
2020-07-21  9:59 ` [PATCH v3 1/3] x86/mm: Pre-allocate p4d/pud pages for vmalloc area Joerg Roedel
2020-07-21 10:44   ` Mike Rapoport
2020-07-27 12:46   ` [tip: x86/mm] x86/mm: Pre-allocate P4D/PUD " tip-bot2 for Joerg Roedel
2020-07-21  9:59 ` [PATCH v3 2/3] x86/mm/64: Do not sync vmalloc/ioremap mappings Joerg Roedel
2020-07-27 12:46   ` [tip: x86/mm] " tip-bot2 for Joerg Roedel
2020-07-21  9:59 ` [PATCH v3 3/3] x86/mm/64: Make sync_global_pgds() static Joerg Roedel
2020-07-27 12:46   ` [tip: x86/mm] " tip-bot2 for Joerg Roedel
2020-07-21 10:44 ` [PATCH v3 0/3] x86/mm/64: Remove vmalloc/ioremap pgtable synchronization Mike Rapoport
2020-07-27 11:08 ` Ingo Molnar
2020-08-14 15:19 [PATCH 1/2] x86/mm/64: Do not sync vmalloc/ioremap mappings Joerg Roedel
2020-08-15 15:46 ` [tip: x86/mm] " tip-bot2 for Joerg Roedel

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).