From 5e8448afe05f2227d9d683f81727864dc4818972 Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Mon, 8 Jan 2018 15:57:12 +0530 Subject: [PATCH 03/26] UBUNTU: SAUCE: rfi-flush: Add barriers to the fallback L1D flushing CVE-2017-5754 Add a hwsync after DCBT_STOP_ALL_STREAM_IDS to order loads/ stores prior to stopping prefetch with loads and stores as a part of the flushing. A lwsync is needed to ensure that after we don't mix the flushing of one congruence class with another Signed-off-by: Balbir Singh Signed-off-by: Stefan Bader --- arch/powerpc/kernel/exceptions-64s.S | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 45dff63..3b73dbb 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -674,13 +674,15 @@ rfi_flush_fallback: addi r12,r12,8 mtctr r11 DCBT_STOP_ALL_STREAM_IDS(r11) /* Stop prefetch streams */ - /* XXX: Should an instruction synchronizing operation be done here? */ + /* order ld/st prior to dcbt stop all streams with flushing */ + hwsync 1: li r8,0 .rept 8 /* 8-way set associative */ ldx r11,r10,r8 add r8,r8,r12 .endr + lwsync /* Ensure that we do all 8 sets before others */ addi r10,r10,128 /* 128 byte cache line */ bdnz 1b @@ -714,13 +716,15 @@ hrfi_flush_fallback: addi r12,r12,8 mtctr r11 DCBT_STOP_ALL_STREAM_IDS(r11) /* Stop prefetch streams */ - /* XXX: Should an instruction synchronizing operation be done here? */ + /* order ld/st prior to dcbt stop all streams with flushing */ + hwsync 1: li r8,0 .rept 8 /* 8-way set associative */ ldx r11,r10,r8 add r8,r8,r12 .endr + lwsync /* Ensure that we do all 8 sets before others */ addi r10,r10,128 /* 128 byte cache line */ bdnz 1b -- 2.7.4