From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Vladimir Murzin <vladimir.murzin@arm.com>
Subject: [PATCH 1/3] mm: fix the MAP_UNINITIALIZED flag
Date: Wed, 3 Jul 2019 05:23:57 -0700 [thread overview]
Message-ID: <20190703122359.18200-2-hch@lst.de> (raw)
In-Reply-To: <20190703122359.18200-1-hch@lst.de>
We can't expose UAPI symbols differently based on CONFIG_ symbols, as
userspace won't have them available. Instead always define the flag,
but only respect it based on the config option.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
arch/xtensa/include/uapi/asm/mman.h | 6 +-----
include/uapi/asm-generic/mman-common.h | 8 +++-----
mm/nommu.c | 4 +++-
3 files changed, 7 insertions(+), 11 deletions(-)
diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h
index be726062412b..ebbb48842190 100644
--- a/arch/xtensa/include/uapi/asm/mman.h
+++ b/arch/xtensa/include/uapi/asm/mman.h
@@ -56,12 +56,8 @@
#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
-#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
-# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
+#define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
* uninitialized */
-#else
-# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
-#endif
/*
* Flags for msync
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index abd238d0f7a4..cb556b430e71 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -19,15 +19,13 @@
#define MAP_TYPE 0x0f /* Mask for type of mapping */
#define MAP_FIXED 0x10 /* Interpret addr exactly */
#define MAP_ANONYMOUS 0x20 /* don't use a file */
-#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
-# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be uninitialized */
-#else
-# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
-#endif
/* 0x0100 - 0x80000 flags are defined in asm-generic/mman.h */
#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
+#define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
+ * uninitialized */
+
/*
* Flags for mlock
*/
diff --git a/mm/nommu.c b/mm/nommu.c
index d8c02fbe03b5..ec75a0dffd4f 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1349,7 +1349,9 @@ unsigned long do_mmap(struct file *file,
add_nommu_region(region);
/* clear anonymous mappings that don't ask for uninitialized data */
- if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
+ if (!vma->vm_file &&
+ (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
+ !(flags & MAP_UNINITIALIZED)))
memset((void *)region->vm_start, 0,
region->vm_end - region->vm_start);
--
2.20.1
next prev parent reply other threads:[~2019-07-03 12:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-03 12:23 nommu fixups Christoph Hellwig
2019-07-03 12:23 ` Christoph Hellwig [this message]
2019-07-03 12:23 ` [PATCH 2/3] mm: provide a print_vma_addr stub for !CONFIG_MMU Christoph Hellwig
2019-07-03 12:23 ` [PATCH 3/3] mm: stub out all of swapops.h " Christoph Hellwig
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