@@ -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)
@@ -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);
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") Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> --- arch/arm64/include/asm/uaccess.h | 6 +++--- arch/arm64/kernel/hw_breakpoint.c | 3 +++ 2 files changed, 6 insertions(+), 3 deletions(-)