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UPSTREAM: arm64: vdso: fix clock_getres for 4GiB-aligned res

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(cherry pick from commit c80ed088a519da53f27b798a69748eaabc66aadf)

The vdso tries to check for a NULL res pointer in __kernel_clock_getres,
but only checks the lower 32 bits as is uses CBZ on the W register the
res pointer is held in.

Thus, if the res pointer happened to be aligned to a 4GiB boundary, we'd
spuriously skip storing the timespec to it, while returning a zero error code
to the caller.

Prevent this by checking the whole pointer, using CBZ on the X register
the res pointer is held in.

Fixes: 9031fefde6 ("arm64: VDSO support")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Andrew Pinski <apinski@cavium.com>
Reported-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Bug: 20045882
Bug: 63737556
Change-Id: Iab5449d8515f9d655e792e3d7ce43a8f016fa2a0
This commit is contained in:
Mark Rutland 2017-10-30 21:23:19 +00:00 • committed by Mark Salyzyn
parent 353c16247d
commit 67a8ab4adc
1 changed files with 1 additions and 1 deletions
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2
arch/arm64/kernel/vdso/gettimeofday.S
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@ -310,7 +310,7 @@ ENTRY(__kernel_clock_getres)
b.ne 4f b.ne 4f
ldr x2, 6f ldr x2, 6f
2: 2:
cbz w1, 3f cbz x1, 3f
stp xzr, x2, [x1] stp xzr, x2, [x1]
3: /* res == NULL. */ 3: /* res == NULL. */