Re: [PATCH 1/3] mm: Make arch_get_unmapped_area() take vm_flags by default

From: Liam R. Howlett <hidden>
Date: 2024-09-03 19:37:09
Also in: linux-alpha, linux-mm, linux-s390, linux-sh, lkml, loongarch, sparclinux

* Mark Brown [off-list ref] [240902 15:09]:

When we introduced arch_get_unmapped_area_vmflags() in 961148704acd
("mm: introduce arch_get_unmapped_area_vmflags()") we did so as part of
properly supporting guard pages for shadow stacks on x86_64, which uses
a custom arch_get_unmapped_area(). Equivalent features are also present
on both arm64 and RISC-V, both of which use the generic implementation
of arch_get_unmapped_area() and will require equivalent modification
there. Rather than continue to deal with having two versions of the
functions let's bite the bullet and have all implementations of
arch_get_unmapped_area() take vm_flags as a parameter.

The new parameter is currently ignored by all implementations other than
x86. The only caller that doesn't have a vm_flags available is
mm_get_unmapped_area(), as for the x86 implementation and the wrapper used
on other architectures this is modified to supply no flags.

No functional changes.

Signed-off-by: Mark Brown <broonie@kernel.org>

I don't love sparc32/sparc64 requires a wide screen monitor, but it
already broke the 80 char limit.

Reviewed-by: Liam R. Howlett <redacted>

quoted hunk ↗ jump to hunk

---
 arch/alpha/kernel/osf_sys.c       |  2 +-
 arch/arc/mm/mmap.c                |  3 ++-
 arch/arm/mm/mmap.c                |  7 ++++---
 arch/csky/abiv1/mmap.c            |  3 ++-
 arch/loongarch/mm/mmap.c          |  5 +++--
 arch/mips/mm/mmap.c               |  2 +-
 arch/parisc/kernel/sys_parisc.c   |  5 +++--
 arch/parisc/mm/hugetlbpage.c      |  2 +-
 arch/powerpc/mm/book3s64/slice.c  |  6 ++++--
 arch/s390/mm/mmap.c               |  4 ++--
 arch/sh/mm/mmap.c                 |  5 +++--
 arch/sparc/kernel/sys_sparc_32.c  |  2 +-
 arch/sparc/kernel/sys_sparc_64.c  |  4 ++--
 arch/x86/include/asm/pgtable_64.h |  1 -
 arch/x86/kernel/sys_x86_64.c      | 21 +++------------------
 arch/xtensa/kernel/syscall.c      |  3 ++-
 include/linux/sched/mm.h          | 23 ++++++++---------------
 mm/mmap.c                         | 31 +++++++------------------------
 18 files changed, 49 insertions(+), 80 deletions(-)

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index e5f881bc8288..8886ab539273 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c

@@ -1229,7 +1229,7 @@ arch_get_unmapped_area_1(unsigned long addr, unsigned long len,
 unsigned long
 arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		       unsigned long len, unsigned long pgoff,
-		       unsigned long flags)
+		       unsigned long flags, vm_flags_t vm_flags)
 {
 	unsigned long limit;

diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c
index 69a915297155..2185afe8d59f 100644
--- a/arch/arc/mm/mmap.c
+++ b/arch/arc/mm/mmap.c

@@ -23,7 +23,8 @@
  */
 unsigned long
 arch_get_unmapped_area(struct file *filp, unsigned long addr,
-		unsigned long len, unsigned long pgoff, unsigned long flags)
+		unsigned long len, unsigned long pgoff,
+		unsigned long flags, vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index d65d0e6ed10a..3dbb383c26d5 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c

@@ -28,7 +28,8 @@
  */
 unsigned long
 arch_get_unmapped_area(struct file *filp, unsigned long addr,
-		unsigned long len, unsigned long pgoff, unsigned long flags)
+		unsigned long len, unsigned long pgoff,
+		unsigned long flags, vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;

@@ -78,8 +79,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 
 unsigned long
 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
-			const unsigned long len, const unsigned long pgoff,
-			const unsigned long flags)
+		        const unsigned long len, const unsigned long pgoff,
+		        const unsigned long flags, vm_flags_t vm_flags)
 {
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;

diff --git a/arch/csky/abiv1/mmap.c b/arch/csky/abiv1/mmap.c
index 7f826331d409..1047865e82a9 100644
--- a/arch/csky/abiv1/mmap.c
+++ b/arch/csky/abiv1/mmap.c

@@ -23,7 +23,8 @@
  */
 unsigned long
 arch_get_unmapped_area(struct file *filp, unsigned long addr,
-		unsigned long len, unsigned long pgoff, unsigned long flags)
+		unsigned long len, unsigned long pgoff,
+		unsigned long flags, vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;

diff --git a/arch/loongarch/mm/mmap.c b/arch/loongarch/mm/mmap.c
index 889030985135..914e82ff3f65 100644
--- a/arch/loongarch/mm/mmap.c
+++ b/arch/loongarch/mm/mmap.c

@@ -89,7 +89,8 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 }
 
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
-	unsigned long len, unsigned long pgoff, unsigned long flags)
+	unsigned long len, unsigned long pgoff, unsigned long flags,
+	vm_flags_t vm_flags)
 {
 	return arch_get_unmapped_area_common(filp,
 			addr0, len, pgoff, flags, UP);

@@ -101,7 +102,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
  */
 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 	unsigned long addr0, unsigned long len, unsigned long pgoff,
-	unsigned long flags)
+	unsigned long flags, vm_flags_t vm_flags)
 {
 	return arch_get_unmapped_area_common(filp,
 			addr0, len, pgoff, flags, DOWN);

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 7e11d7b58761..02bf5353efbd 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c

@@ -110,7 +110,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
  */
 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 	unsigned long addr0, unsigned long len, unsigned long pgoff,
-	unsigned long flags)
+	unsigned long flags, vm_flags_t vm_flags)
 {
 	return arch_get_unmapped_area_common(filp,
 			addr0, len, pgoff, flags, DOWN);

diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index f7722451276e..f852fe274abe 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c

@@ -167,7 +167,8 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 }
 
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
-	unsigned long len, unsigned long pgoff, unsigned long flags)
+	unsigned long len, unsigned long pgoff, unsigned long flags,
+	vm_flags_t vm_flags)
 {
 	return arch_get_unmapped_area_common(filp,
 			addr, len, pgoff, flags, UP);

@@ -175,7 +176,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 
 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 	unsigned long addr, unsigned long len, unsigned long pgoff,
-	unsigned long flags)
+	unsigned long flags, vm_flags_t vm_flags)
 {
 	return arch_get_unmapped_area_common(filp,
 			addr, len, pgoff, flags, DOWN);

diff --git a/arch/parisc/mm/hugetlbpage.c b/arch/parisc/mm/hugetlbpage.c
index 0356199bd9e7..aa664f7ddb63 100644
--- a/arch/parisc/mm/hugetlbpage.c
+++ b/arch/parisc/mm/hugetlbpage.c

@@ -40,7 +40,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 		addr = ALIGN(addr, huge_page_size(h));
 
 	/* we need to make sure the colouring is OK */
-	return arch_get_unmapped_area(file, addr, len, pgoff, flags);
+	return arch_get_unmapped_area(file, addr, len, pgoff, flags, 0);
 }

diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c
index ef3ce37f1bb3..ada6bf896ef8 100644
--- a/arch/powerpc/mm/book3s64/slice.c
+++ b/arch/powerpc/mm/book3s64/slice.c

@@ -637,7 +637,8 @@ unsigned long arch_get_unmapped_area(struct file *filp,
 				     unsigned long addr,
 				     unsigned long len,
 				     unsigned long pgoff,
-				     unsigned long flags)
+				     unsigned long flags,
+				     vm_flags_t vm_flags)
 {
 	if (radix_enabled())
 		return generic_get_unmapped_area(filp, addr, len, pgoff, flags);

@@ -650,7 +651,8 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 					     const unsigned long addr0,
 					     const unsigned long len,
 					     const unsigned long pgoff,
-					     const unsigned long flags)
+					     const unsigned long flags,
+					     vm_flags_t vm_flags)
 {
 	if (radix_enabled())
 		return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 206756946589..96efa061ce01 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c

@@ -82,7 +82,7 @@ static int get_align_mask(struct file *filp, unsigned long flags)
 
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 				     unsigned long len, unsigned long pgoff,
-				     unsigned long flags)
+				     unsigned long flags, vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;

@@ -117,7 +117,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 
 unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 					     unsigned long len, unsigned long pgoff,
-					     unsigned long flags)
+					     unsigned long flags, vm_flags_t vm_flags)
 {
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;

diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
index bee329d4149a..c442734d9b0c 100644
--- a/arch/sh/mm/mmap.c
+++ b/arch/sh/mm/mmap.c

@@ -52,7 +52,8 @@ static inline unsigned long COLOUR_ALIGN(unsigned long addr,
 }
 
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
-	unsigned long len, unsigned long pgoff, unsigned long flags)
+	unsigned long len, unsigned long pgoff, unsigned long flags,
+	vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;

@@ -99,7 +100,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 unsigned long
 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 			  const unsigned long len, const unsigned long pgoff,
-			  const unsigned long flags)
+			  const unsigned long flags, vm_flags_t vm_flags)
 {
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;

diff --git a/arch/sparc/kernel/sys_sparc_32.c b/arch/sparc/kernel/sys_sparc_32.c
index 08a19727795c..80822f922e76 100644
--- a/arch/sparc/kernel/sys_sparc_32.c
+++ b/arch/sparc/kernel/sys_sparc_32.c

@@ -39,7 +39,7 @@ SYSCALL_DEFINE0(getpagesize)
 	return PAGE_SIZE; /* Possibly older binaries want 8192 on sun4's? */
 }
 
-unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags)
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
 {
 	struct vm_unmapped_area_info info = {};

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index d9c3b34ca744..acade309dc2f 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c

@@ -87,7 +87,7 @@ static inline unsigned long COLOR_ALIGN(unsigned long addr,
 	return base + off;
 }
 
-unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags)
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct * vma;

@@ -146,7 +146,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
 unsigned long
 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 			  const unsigned long len, const unsigned long pgoff,
-			  const unsigned long flags)
+			  const unsigned long flags, vm_flags_t vm_flags)
 {
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;

diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 3c4407271d08..7e9db77231ac 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h

@@ -245,7 +245,6 @@ extern void cleanup_highmap(void);
 
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
-#define HAVE_ARCH_UNMAPPED_AREA_VMFLAGS
 
 #define PAGE_AGP    PAGE_KERNEL_NOCACHE
 #define HAVE_PAGE_AGP 1

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 01d7cd85ef97..87f8c9a71c49 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c

@@ -121,7 +121,7 @@ static inline unsigned long stack_guard_placement(vm_flags_t vm_flags)
 }
 
 unsigned long
-arch_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, unsigned long len,
+arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
 		       unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
 {
 	struct mm_struct *mm = current->mm;

@@ -158,7 +158,7 @@ arch_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, unsigned l
 }
 
 unsigned long
-arch_get_unmapped_area_topdown_vmflags(struct file *filp, unsigned long addr0,
+arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr0,
 			  unsigned long len, unsigned long pgoff,
 			  unsigned long flags, vm_flags_t vm_flags)
 {

@@ -228,20 +228,5 @@ arch_get_unmapped_area_topdown_vmflags(struct file *filp, unsigned long addr0,
 	 * can happen with large stack limits and large mmap()
 	 * allocations.
 	 */
-	return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
-}
-
-unsigned long
-arch_get_unmapped_area(struct file *filp, unsigned long addr,
-		unsigned long len, unsigned long pgoff, unsigned long flags)
-{
-	return arch_get_unmapped_area_vmflags(filp, addr, len, pgoff, flags, 0);
-}
-
-unsigned long
-arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
-			  const unsigned long len, const unsigned long pgoff,
-			  const unsigned long flags)
-{
-	return arch_get_unmapped_area_topdown_vmflags(filp, addr, len, pgoff, flags, 0);
+	return arch_get_unmapped_area(filp, addr0, len, pgoff, flags, 0);
 }

diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index b3c2450d6f23..7f048d368dba 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c

@@ -55,7 +55,8 @@ asmlinkage long xtensa_fadvise64_64(int fd, int advice,
 
 #ifdef CONFIG_MMU
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
-		unsigned long len, unsigned long pgoff, unsigned long flags)
+		unsigned long len, unsigned long pgoff, unsigned long flags,
+		vm_flgs_t vm_flags)
 {
 	struct vm_area_struct *vmm;
 	struct vma_iterator vmi;

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 91546493c43d..c4d34abc45d4 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h

@@ -179,27 +179,20 @@ static inline void mm_update_next_owner(struct mm_struct *mm)
 
 extern void arch_pick_mmap_layout(struct mm_struct *mm,
 				  struct rlimit *rlim_stack);
-extern unsigned long
-arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
-		       unsigned long, unsigned long);
-extern unsigned long
+
+unsigned long
+arch_get_unmapped_area(struct file *filp, unsigned long addr,
+		       unsigned long len, unsigned long pgoff,
+		       unsigned long flags, vm_flags_t vm_flags);
+unsigned long
 arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
-			  unsigned long len, unsigned long pgoff,
-			  unsigned long flags);
+			       unsigned long len, unsigned long pgoff,
+			       unsigned long flags, vm_flags_t);
 
 unsigned long mm_get_unmapped_area(struct mm_struct *mm, struct file *filp,
 				   unsigned long addr, unsigned long len,
 				   unsigned long pgoff, unsigned long flags);
 
-unsigned long
-arch_get_unmapped_area_vmflags(struct file *filp, unsigned long addr,
-			       unsigned long len, unsigned long pgoff,
-			       unsigned long flags, vm_flags_t vm_flags);
-unsigned long
-arch_get_unmapped_area_topdown_vmflags(struct file *filp, unsigned long addr,
-				       unsigned long len, unsigned long pgoff,
-				       unsigned long flags, vm_flags_t);
-
 unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm,
 					   struct file *filp,
 					   unsigned long addr,

diff --git a/mm/mmap.c b/mm/mmap.c
index d0dfc85b209b..7528146f886f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c

@@ -1821,7 +1821,7 @@ generic_get_unmapped_area(struct file *filp, unsigned long addr,
 unsigned long
 arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		       unsigned long len, unsigned long pgoff,
-		       unsigned long flags)
+		       unsigned long flags, vm_flags_t vm_flags)
 {
 	return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
 }

@@ -1885,38 +1885,21 @@ generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 unsigned long
 arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 			       unsigned long len, unsigned long pgoff,
-			       unsigned long flags)
+			       unsigned long flags, vm_flags_t vm_flags)
 {
 	return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
 }
 #endif
 
-#ifndef HAVE_ARCH_UNMAPPED_AREA_VMFLAGS
-unsigned long
-arch_get_unmapped_area_vmflags(struct file *filp, unsigned long addr, unsigned long len,
-			       unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
-{
-	return arch_get_unmapped_area(filp, addr, len, pgoff, flags);
-}
-
-unsigned long
-arch_get_unmapped_area_topdown_vmflags(struct file *filp, unsigned long addr,
-				       unsigned long len, unsigned long pgoff,
-				       unsigned long flags, vm_flags_t vm_flags)
-{
-	return arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
-}
-#endif
-
 unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, struct file *filp,
 					   unsigned long addr, unsigned long len,
 					   unsigned long pgoff, unsigned long flags,
 					   vm_flags_t vm_flags)
 {
 	if (test_bit(MMF_TOPDOWN, &mm->flags))
-		return arch_get_unmapped_area_topdown_vmflags(filp, addr, len, pgoff,
-							      flags, vm_flags);
-	return arch_get_unmapped_area_vmflags(filp, addr, len, pgoff, flags, vm_flags);
+		return arch_get_unmapped_area_topdown(filp, addr, len, pgoff,
+						      flags, vm_flags);
+	return arch_get_unmapped_area(filp, addr, len, pgoff, flags, vm_flags);
 }
 
 unsigned long

@@ -1978,8 +1961,8 @@ mm_get_unmapped_area(struct mm_struct *mm, struct file *file,
 		     unsigned long pgoff, unsigned long flags)
 {
 	if (test_bit(MMF_TOPDOWN, &mm->flags))
-		return arch_get_unmapped_area_topdown(file, addr, len, pgoff, flags);
-	return arch_get_unmapped_area(file, addr, len, pgoff, flags);
+		return arch_get_unmapped_area_topdown(file, addr, len, pgoff, flags, 0);
+	return arch_get_unmapped_area(file, addr, len, pgoff, flags, 0);
 }
 EXPORT_SYMBOL(mm_get_unmapped_area);

-- 
2.39.2

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