diff options
| author | Kristina Martsenko <kristina.martsenko@arm.com> | 2017-06-06 20:14:09 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-14 15:06:05 +0200 |
| commit | 1d61ccb5ac272b6cddc50c542646d2b35f87de8d (patch) | |
| tree | 135c8bc2bcd00520e78b6101d7cdc65223d35245 /arch | |
| parent | 791d94ef40f6b9c2e809bd118d1b3423e7514d37 (diff) | |
arm64: hw_breakpoint: fix watchpoint matching for tagged pointers
commit 7dcd9dd8cebe9fa626af7e2358d03a37041a70fb upstream.
This backport has a small difference from the upstream commit:
- The address tag is removed in watchpoint_handler() instead of
get_distance_from_watchpoint(), because 4.9 does not have commit
fdfeff0f9e3d ("arm64: hw_breakpoint: Handle inexact watchpoint
addresses").
Original patch description:
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")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 6 | ||||
| -rw-r--r-- | arch/arm64/kernel/hw_breakpoint.c | 3 |
2 files changed, 5 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 14cca10aeb4e..811cf16a65f9 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -105,9 +105,9 @@ 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 948b73148d56..0b9e5f6290f9 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]); @@ -696,7 +697,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr, /* Check if the watchpoint value matches. */ val = read_wb_reg(AARCH64_DBG_REG_WVR, i); - if (val != (addr & ~alignment_mask)) + if (val != (untagged_addr(addr) & ~alignment_mask)) goto unlock; /* Possible match, check the byte address select to confirm. */ |