diff options
| author | Vincenzo Frascino <vincenzo.frascino@arm.com> | 2019-04-01 12:30:14 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-22 07:37:36 +0200 |
| commit | 26e7d2ad97b9dcc1a4618d0803847a31fc013e86 (patch) | |
| tree | 838d379a97f32df2d27672fc075d162688379dd9 /arch | |
| parent | 6d696ceb15a31bedf89b3c572bf62b64fe5d69c4 (diff) | |
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>
Diffstat (limited to 'arch')
| -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 79657ad91397..def5a5e807f0 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -53,7 +53,15 @@ * 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) ? \ |