This is a note to let you know that I've just added the patch titled

powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: powerpc-64s-convert-slb_miss_common-to-use-rfi_to_user-kernel.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From c7305645eb0c1621351cfc104038831ae87c0053 Mon Sep 17 00:00:00 2001

From: Nicholas Piggin npiggin@gmail.com Date: Wed, 10 Jan 2018 03:07:15 +1100 Subject: powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL

From: Nicholas Piggin npiggin@gmail.com

commit c7305645eb0c1621351cfc104038831ae87c0053 upstream.

In the SLB miss handler we may be returning to user or kernel. We need to add a check early on and save the result in the cr4 register, and then we bifurcate the return path based on that.

Signed-off-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Nicholas Piggin npiggin@gmail.com [mpe: Backport to 4.4 based on patch from Balbir] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/kernel/exceptions-64s.S | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)

--- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1503,6 +1503,8 @@ slb_miss_realmode:

andi. r10,r12,MSR_RI /* check for unrecoverable exception */ beq- 2f + andi. r10,r12,MSR_PR /* check for user mode (PR != 0) */ + bne 1f

.machine push .machine "power4" @@ -1516,7 +1518,23 @@ slb_miss_realmode: ld r11,PACA_EXSLB+EX_R11(r13) ld r12,PACA_EXSLB+EX_R12(r13) ld r13,PACA_EXSLB+EX_R13(r13) - rfid + RFI_TO_KERNEL + b . /* prevent speculative execution */ + +1: +.machine push +.machine "power4" + mtcrf 0x80,r9 + mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */ +.machine pop + + RESTORE_PPR_PACA(PACA_EXSLB, r9) + ld r9,PACA_EXSLB+EX_R9(r13) + ld r10,PACA_EXSLB+EX_R10(r13) + ld r11,PACA_EXSLB+EX_R11(r13) + ld r12,PACA_EXSLB+EX_R12(r13) + ld r13,PACA_EXSLB+EX_R13(r13) + RFI_TO_USER b . /* prevent speculative execution */

2: mfspr r11,SPRN_SRR0 @@ -1525,7 +1543,7 @@ slb_miss_realmode: mtspr SPRN_SRR0,r10 ld r10,PACAKMSR(r13) mtspr SPRN_SRR1,r10 - rfid + RFI_TO_KERNEL b .

unrecov_slb:

Patches currently in stable-queue which might be from npiggin@gmail.com are

queue-4.4/powerpc-64s-simple-rfi-macro-conversions.patch queue-4.4/powerpc-64-add-macros-for-annotating-the-destination-of-rfid-hrfid.patch queue-4.4/powerpc-64s-allow-control-of-rfi-flush-via-debugfs.patch queue-4.4/powerpc-64s-convert-slb_miss_common-to-use-rfi_to_user-kernel.patch queue-4.4/powerpc-64-convert-the-syscall-exit-path-to-use-rfi_to_user-kernel.patch queue-4.4/powerpc-64s-add-support-for-rfi-flush-of-l1-d-cache.patch queue-4.4/powerpc-64-convert-fast_exception_return-to-use-rfi_to_user-kernel.patch