diff options
| author | Kristina Martsenko <kristina.martsenko@arm.com> | 2017-05-03 16:37:46 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2017-05-09 17:26:40 +0100 |
| commit | 7dcd9dd8cebe9fa626af7e2358d03a37041a70fb (patch) | |
| tree | 45bbe17e3f608ba637e25fab2d12e39f1dc95cc8 | |
| parent | 81cddd65b5c82758ea5571a25e31ff6f1f89ff02 (diff) | |
arm64: hw_breakpoint: fix watchpoint matching for tagged pointers
When we take a watchpoint exception, the address that triggered the
watchpoint is found in FAR_EL1. We compare it to the address of each
configured watchpoint to see which one was hit.
The configured watchpoint addresses are untagged, while the address in
FAR_EL1 will have an address tag if the data access was done using a
tagged address. The tag needs to be removed to compare the address to
the watchpoints.
Currently we don't remove it, and as a result can report the wrong
watchpoint as being hit (specifically, always either the highest TTBR0
watchpoint or lowest TTBR1 watchpoint). This patch removes the tag.
Fixes: d50240a5f6ce ("arm64: mm: permit use of tagged pointers at EL0")
Cc: <stable@vger.kernel.org> # 3.12.x-
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 6 | ||||
| -rw-r--r-- | arch/arm64/kernel/hw_breakpoint.c | 3 |
2 files changed, 6 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 5308d696311b..0221029e27ff 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -106,9 +106,9 @@ static inline void set_fs(mm_segment_t fs) }) /* - * When dealing with data aborts or instruction traps we may end up with - * a tagged userland pointer. Clear the tag to get a sane pointer to pass - * on to access_ok(), for instance. + * When dealing with data aborts, watchpoints, or instruction traps we may end + * up with a tagged userland pointer. Clear the tag to get a sane pointer to + * pass on to access_ok(), for instance. */ #define untagged_addr(addr) sign_extend64(addr, 55) diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index 0296e7924240..749f81779420 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -36,6 +36,7 @@ #include <asm/traps.h> #include <asm/cputype.h> #include <asm/system_misc.h> +#include <asm/uaccess.h> /* Breakpoint currently in use for each BRP. */ static DEFINE_PER_CPU(struct perf_event *, bp_on_reg[ARM_MAX_BRP]); @@ -721,6 +722,8 @@ static u64 get_distance_from_watchpoint(unsigned long addr, u64 val, u64 wp_low, wp_high; u32 lens, lene; + addr = untagged_addr(addr); + lens = __ffs(ctrl->len); lene = __fls(ctrl->len); |