On 9/1/16 11:46 PM, Thiago Jung Bauermann wrote:
Am Freitag, 26 August 2016, 11:50:10 schrieb Rui Teng:
The same logic appears twice and should probably be pulled out into a
function.
Suggested-by: Michael Ellerman <m...@ellerman.id.au>
Signed-off-by: Rui Teng <rui.t...@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 45
+++++++++++++++++------------------------ 1 file changed, 19
insertions(+), 26 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c
b/arch/powerpc/mm/hash_utils_64.c index 0821556..69ef702 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1460,6 +1460,23 @@ out_exit:
local_irq_restore(flags);
}
+/*
+ * Transactions are not aborted by tlbiel, only tlbie.
+ * Without, syncing a page back to a block device w/ PIO could pick up
+ * transactional data (bad!) so we force an abort here. Before the
+ * sync the page will be made read-only, which will flush_hash_page.
+ * BIG ISSUE here: if the kernel uses a page from userspace without
+ * unmapping it first, it may see the speculated version.
+ */
+void local_tm_abort(int local)
+{
+ if (local && cpu_has_feature(CPU_FTR_TM) && current->thread.regs &&
+ MSR_TM_ACTIVE(current->thread.regs->msr)) {
+ tm_enable();
+ tm_abort(TM_CAUSE_TLBI);
+ }
+}
+
Since local_tm_abort is only used in this file, it should be static.
OK
Also, since both places calling it are guarded by
CONFIG_PPC_TRANSACTIONAL_MEM, wouldn't it be cleaner if the #ifdef was here
instead and the #else block defined an empty static inline function? Then
the call sites wouldn't need to be guarded.
I have considered this style before, but I am worried about the call
stacks increased by empty function and forgot the inline function.
Will send v2 with your comments.
Thanks!
