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From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
To: <linux-kernel@vger.kernel.org>
Cc: <linux-mips@linux-mips.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Victor Kamensky <victor.kamensky@linaro.org>
Subject: [PATCH] uprobes: allow for a cache flush after ixol breakpoint creation
Date: Tue, 13 Dec 2016 11:40:57 +0100	[thread overview]
Message-ID: <1481625657-22850-1-git-send-email-marcin.nowakowski@imgtec.com> (raw)

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: Peter Zijlstra <peterz@infradead.org>
CC: Ingo Molnar <mingo@redhat.com>
CC: Arnaldo Carvalho de Melo <acme@kernel.org>
CC: Alexander Shishkin <alexander.shishkin@linux.intel.com>
CC: Victor Kamensky <victor.kamensky@linaro.org>

---
 kernel/events/uprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f9ec9ad..b5916b4 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -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;
-- 
2.7.4

             reply	other threads:[~2016-12-13 10:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-13 10:40 Marcin Nowakowski [this message]
2016-12-20  7:58 ` [tip:perf/urgent] uprobes: Fix uprobes on MIPS, " tip-bot for Marcin Nowakowski
2016-12-20 13:08   ` Oleg Nesterov
2016-12-20 15:21     ` Marcin Nowakowski
2016-12-20 17:50       ` Oleg Nesterov
2016-12-21 11:24         ` Ralf Baechle

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