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 4.14-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-4.14 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: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/kernel/exceptions-64s.S | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-)

--- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -596,6 +596,9 @@ EXC_COMMON_BEGIN(slb_miss_common) stw r9,PACA_EXSLB+EX_CCR(r13) /* save CR in exc. frame */ std r10,PACA_EXSLB+EX_LR(r13) /* save LR */

+ andi. r9,r11,MSR_PR // Check for exception from userspace + cmpdi cr4,r9,MSR_PR // And save the result in CR4 for later + /* * Test MSR_RI before calling slb_allocate_realmode, because the * MSR in r11 gets clobbered. However we still want to allocate @@ -622,9 +625,32 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_R

/* All done -- return from exception. */

+ bne cr4,1f /* returning to kernel */ + +.machine push +.machine "power4" + mtcrf 0x80,r9 + mtcrf 0x08,r9 /* MSR[PR] indication is in cr4 */ + mtcrf 0x04,r9 /* MSR[RI] indication is in cr5 */ + mtcrf 0x02,r9 /* I/D indication is in cr6 */ + mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */ +.machine pop + + RESTORE_CTR(r9, PACA_EXSLB) + RESTORE_PPR_PACA(PACA_EXSLB, r9) + mr r3,r12 + 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 */ +1: .machine push .machine "power4" mtcrf 0x80,r9 + mtcrf 0x08,r9 /* MSR[PR] indication is in cr4 */ mtcrf 0x04,r9 /* MSR[RI] indication is in cr5 */ mtcrf 0x02,r9 /* I/D indication is in cr6 */ mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */ @@ -638,9 +664,10 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_R 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 */

+ 2: std r3,PACA_EXSLB+EX_DAR(r13) mr r3,r12 mfspr r11,SPRN_SRR0

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

queue-4.14/powerpc-64s-simple-rfi-macro-conversions.patch queue-4.14/powerpc-64-add-macros-for-annotating-the-destination-of-rfid-hrfid.patch queue-4.14/powerpc-64s-convert-slb_miss_common-to-use-rfi_to_user-kernel.patch queue-4.14/powerpc-64-convert-the-syscall-exit-path-to-use-rfi_to_user-kernel.patch queue-4.14/powerpc-64s-add-support-for-rfi-flush-of-l1-d-cache.patch queue-4.14/powerpc-64-convert-fast_exception_return-to-use-rfi_to_user-kernel.patch