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| author | Vincenzo Frascino <vincenzo.frascino@arm.com> | 2019-04-01 14:30:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-21 19:50:14 +0300 |
| commit | 45514ea4f2298e8bab3597c33ed24d5bbb0abf09 (patch) | |
| tree | ef53f02afaa114414918ca7f534fb3f5204beec6 | |
| parent | d43a4430d510f84b93ceb94d76ed65bb7b0b020d (diff) | |
| download | linux-45514ea4f2298e8bab3597c33ed24d5bbb0abf09.tar.xz | |
arm64: compat: Reduce address limit
commit d263119387de9975d2acba1dfd3392f7c5979c18 upstream.
Currently, compat tasks running on arm64 can allocate memory up to
TASK_SIZE_32 (UL(0x100000000)).
This means that mmap() allocations, if we treat them as returning an
array, are not compliant with the sections 6.5.8 of the C standard
(C99) which states that: "If the expression P points to an element of
an array object and the expression Q points to the last element of the
same array object, the pointer expression Q+1 compares greater than P".
Redefine TASK_SIZE_32 to address the issue.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: <stable@vger.kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
[will: fixed typo in comment]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/include/asm/processor.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index fda6f5812281..91bb97d8bdbf 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -49,7 +49,15 @@ * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area. */ #ifdef CONFIG_COMPAT +#ifdef CONFIG_ARM64_64K_PAGES +/* + * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied + * by the compat vectors page. + */ #define TASK_SIZE_32 UL(0x100000000) +#else +#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE) +#endif /* CONFIG_ARM64_64K_PAGES */ #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ |