uprobes: Fix uprobes on MIPS, allow for a cache flush after ixol breakpoint creation
authorMarcin Nowakowski <marcin.nowakowski@imgtec.com>
Tue, 13 Dec 2016 10:40:57 +0000 (11:40 +0100)
committerIngo Molnar <mingo@kernel.org>
Sun, 18 Dec 2016 08:42:11 +0000 (09:42 +0100)
Commit:

  72e6ae285a1d ('ARM: 8043/1: uprobes need icache flush after xol write'

... has introduced an arch-specific method to ensure all caches are
flushed appropriately after an instruction is written to an XOL page.

However, when the XOL area is created and the out-of-line breakpoint
instruction is copied, caches are not flushed at all and stale data may
be found in icache.

Replace a simple copy_to_page() with arch_uprobe_copy_ixol() to allow
the arch to ensure all caches are updated accordingly.

This change fixes uprobes on MIPS InterAptiv (tested on Creator Ci40).

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/1481625657-22850-1-git-send-email-marcin.nowakowski@imgtec.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/events/uprobes.c

index f9ec9ad..b5916b4 100644 (file)
@@ -1194,7 +1194,7 @@ static struct xol_area *__create_xol_area(unsigned long vaddr)
        /* Reserve the 1st slot for get_trampoline_vaddr() */
        set_bit(0, area->bitmap);
        atomic_set(&area->slot_count, 1);
-       copy_to_page(area->pages[0], 0, &insn, UPROBE_SWBP_INSN_SIZE);
+       arch_uprobe_copy_ixol(area->pages[0], 0, &insn, UPROBE_SWBP_INSN_SIZE);
 
        if (!xol_add_vma(mm, area))
                return area;