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* [PATCH 0/8] Fix mmap base in bottom-up mmap
@ 2019-06-19  5:08 Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 1/8] s390: Start fallback of top-down mmap at mm->mmap_base Alexandre Ghiti
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Alexandre Ghiti @ 2019-06-19  5:08 UTC (permalink / raw)
  To: Andrew Morton
  Cc: James E . J . Bottomley, Helge Deller, Heiko Carstens,
	Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
	Rich Felker, David S . Miller, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H . Peter Anvin, x86, Dave Hansen,
	Andy Lutomirski, Peter Zijlstra, linux-parisc, linux-kernel,
	linux-s390, linux-sh, sparclinux, linux-mm, Alexandre Ghiti

This series fixes the fallback of the top-down mmap: in case of
failure, a bottom-up scheme can be tried as a last resort between
the top-down mmap base and the stack, hoping for a large unused stack
limit.

Lots of architectures and even mm code start this fallback
at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
already failed on the whole address space: instead, simply use
mmap_base.

Along the way, it allows to get rid of of mmap_legacy_base and
mmap_compat_legacy_base from mm_struct.

Note that arm and mips already implement this behaviour. 

Alexandre Ghiti (8):
  s390: Start fallback of top-down mmap at mm->mmap_base
  sh: Start fallback of top-down mmap at mm->mmap_base
  sparc: Start fallback of top-down mmap at mm->mmap_base
  x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
  mm: Start fallback top-down mmap at mm->mmap_base
  parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
    bottom-up mmap
  x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for bottom-up
    mmap
  mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
    mm_struct

 arch/parisc/kernel/sys_parisc.c  |  8 +++-----
 arch/s390/mm/mmap.c              |  2 +-
 arch/sh/mm/mmap.c                |  2 +-
 arch/sparc/kernel/sys_sparc_64.c |  2 +-
 arch/sparc/mm/hugetlbpage.c      |  2 +-
 arch/x86/include/asm/elf.h       |  2 +-
 arch/x86/kernel/sys_x86_64.c     |  4 ++--
 arch/x86/mm/hugetlbpage.c        |  7 ++++---
 arch/x86/mm/mmap.c               | 20 +++++++++-----------
 include/linux/mm_types.h         |  2 --
 mm/debug.c                       |  4 ++--
 mm/mmap.c                        |  2 +-
 12 files changed, 26 insertions(+), 31 deletions(-)

-- 
2.20.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 1/8] s390: Start fallback of top-down mmap at mm->mmap_base
  2019-06-19  5:08 [PATCH 0/8] Fix mmap base in bottom-up mmap Alexandre Ghiti
@ 2019-06-19  5:08 ` Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 2/8] sh: " Alexandre Ghiti
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Alexandre Ghiti @ 2019-06-19  5:08 UTC (permalink / raw)
  To: Andrew Morton
  Cc: James E . J . Bottomley, Helge Deller, Heiko Carstens,
	Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
	Rich Felker, David S . Miller, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H . Peter Anvin, x86, Dave Hansen,
	Andy Lutomirski, Peter Zijlstra, linux-parisc, linux-kernel,
	linux-s390, linux-sh, sparclinux, linux-mm, Alexandre Ghiti

In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
 arch/s390/mm/mmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index cbc718ba6d78..4a222969843b 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -166,7 +166,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (addr & ~PAGE_MASK) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = mm->mmap_base;
 		info.high_limit = TASK_SIZE;
 		addr = vm_unmapped_area(&info);
 		if (addr & ~PAGE_MASK)
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 2/8] sh: Start fallback of top-down mmap at mm->mmap_base
  2019-06-19  5:08 [PATCH 0/8] Fix mmap base in bottom-up mmap Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 1/8] s390: Start fallback of top-down mmap at mm->mmap_base Alexandre Ghiti
@ 2019-06-19  5:08 ` Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 3/8] sparc: " Alexandre Ghiti
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Alexandre Ghiti @ 2019-06-19  5:08 UTC (permalink / raw)
  To: Andrew Morton
  Cc: James E . J . Bottomley, Helge Deller, Heiko Carstens,
	Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
	Rich Felker, David S . Miller, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H . Peter Anvin, x86, Dave Hansen,
	Andy Lutomirski, Peter Zijlstra, linux-parisc, linux-kernel,
	linux-s390, linux-sh, sparclinux, linux-mm, Alexandre Ghiti

In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
 arch/sh/mm/mmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
index 6a1a1297baae..4c7da92473dd 100644
--- a/arch/sh/mm/mmap.c
+++ b/arch/sh/mm/mmap.c
@@ -135,7 +135,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (addr & ~PAGE_MASK) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = mm->mmap_base;
 		info.high_limit = TASK_SIZE;
 		addr = vm_unmapped_area(&info);
 	}
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 3/8] sparc: Start fallback of top-down mmap at mm->mmap_base
  2019-06-19  5:08 [PATCH 0/8] Fix mmap base in bottom-up mmap Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 1/8] s390: Start fallback of top-down mmap at mm->mmap_base Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 2/8] sh: " Alexandre Ghiti
@ 2019-06-19  5:08 ` Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 4/8] x86, hugetlbpage: " Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 5/8] mm: Start fallback " Alexandre Ghiti
  4 siblings, 0 replies; 6+ messages in thread
From: Alexandre Ghiti @ 2019-06-19  5:08 UTC (permalink / raw)
  To: Andrew Morton
  Cc: James E . J . Bottomley, Helge Deller, Heiko Carstens,
	Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
	Rich Felker, David S . Miller, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H . Peter Anvin, x86, Dave Hansen,
	Andy Lutomirski, Peter Zijlstra, linux-parisc, linux-kernel,
	linux-s390, linux-sh, sparclinux, linux-mm, Alexandre Ghiti

In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
 arch/sparc/kernel/sys_sparc_64.c | 2 +-
 arch/sparc/mm/hugetlbpage.c      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index ccc88926bc00..ea1de1e5fa8d 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -206,7 +206,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (addr & ~PAGE_MASK) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = mm->mmap_base;
 		info.high_limit = STACK_TOP32;
 		addr = vm_unmapped_area(&info);
 	}
diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index f78793a06bbd..9c67f805abc8 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -86,7 +86,7 @@ hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (addr & ~PAGE_MASK) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = mm->mmap_base;
 		info.high_limit = STACK_TOP32;
 		addr = vm_unmapped_area(&info);
 	}
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 4/8] x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
  2019-06-19  5:08 [PATCH 0/8] Fix mmap base in bottom-up mmap Alexandre Ghiti
                   ` (2 preceding siblings ...)
  2019-06-19  5:08 ` [PATCH 3/8] sparc: " Alexandre Ghiti
@ 2019-06-19  5:08 ` Alexandre Ghiti
  2019-06-19  5:08 ` [PATCH 5/8] mm: Start fallback " Alexandre Ghiti
  4 siblings, 0 replies; 6+ messages in thread
From: Alexandre Ghiti @ 2019-06-19  5:08 UTC (permalink / raw)
  To: Andrew Morton
  Cc: James E . J . Bottomley, Helge Deller, Heiko Carstens,
	Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
	Rich Felker, David S . Miller, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H . Peter Anvin, x86, Dave Hansen,
	Andy Lutomirski, Peter Zijlstra, linux-parisc, linux-kernel,
	linux-s390, linux-sh, sparclinux, linux-mm, Alexandre Ghiti

In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
 arch/x86/mm/hugetlbpage.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index fab095362c50..4b90339aef50 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -106,11 +106,12 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 {
 	struct hstate *h = hstate_file(file);
 	struct vm_unmapped_area_info info;
+	unsigned long mmap_base = get_mmap_base(0);
 
 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
 	info.low_limit = PAGE_SIZE;
-	info.high_limit = get_mmap_base(0);
+	info.high_limit = mmap_base;
 
 	/*
 	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
@@ -132,7 +133,7 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
 	if (addr & ~PAGE_MASK) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = mmap_base;
 		info.high_limit = TASK_SIZE_LOW;
 		addr = vm_unmapped_area(&info);
 	}
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 5/8] mm: Start fallback top-down mmap at mm->mmap_base
  2019-06-19  5:08 [PATCH 0/8] Fix mmap base in bottom-up mmap Alexandre Ghiti
                   ` (3 preceding siblings ...)
  2019-06-19  5:08 ` [PATCH 4/8] x86, hugetlbpage: " Alexandre Ghiti
@ 2019-06-19  5:08 ` Alexandre Ghiti
  4 siblings, 0 replies; 6+ messages in thread
From: Alexandre Ghiti @ 2019-06-19  5:08 UTC (permalink / raw)
  To: Andrew Morton
  Cc: James E . J . Bottomley, Helge Deller, Heiko Carstens,
	Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
	Rich Felker, David S . Miller, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H . Peter Anvin, x86, Dave Hansen,
	Andy Lutomirski, Peter Zijlstra, linux-parisc, linux-kernel,
	linux-s390, linux-sh, sparclinux, linux-mm, Alexandre Ghiti

In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
 mm/mmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index dedae10cb6e2..e563145c1ff4 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2185,7 +2185,7 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 	if (offset_in_page(addr)) {
 		VM_BUG_ON(addr != -ENOMEM);
 		info.flags = 0;
-		info.low_limit = TASK_UNMAPPED_BASE;
+		info.low_limit = arch_get_mmap_base(addr, mm->mmap_base);
 		info.high_limit = mmap_end;
 		addr = vm_unmapped_area(&info);
 	}
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2019-06-19  5:15 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2019-06-19  5:08 [PATCH 0/8] Fix mmap base in bottom-up mmap Alexandre Ghiti
2019-06-19  5:08 ` [PATCH 1/8] s390: Start fallback of top-down mmap at mm->mmap_base Alexandre Ghiti
2019-06-19  5:08 ` [PATCH 2/8] sh: " Alexandre Ghiti
2019-06-19  5:08 ` [PATCH 3/8] sparc: " Alexandre Ghiti
2019-06-19  5:08 ` [PATCH 4/8] x86, hugetlbpage: " Alexandre Ghiti
2019-06-19  5:08 ` [PATCH 5/8] mm: Start fallback " Alexandre Ghiti

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