This is a note to let you know that I've just added the patch titled
powerpc/64: Convert fast_exception_return 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;a=summary
The filename of the patch is:
powerpc-64-convert-fast_exception_return-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@xxxxxxxxxxxxxxx> know about it.
>From a08f828cf47e6c605af21d2cdec68f84e799c318 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@xxxxxxxxx>
Date: Wed, 10 Jan 2018 03:07:15 +1100
Subject: powerpc/64: Convert fast_exception_return to use RFI_TO_USER/KERNEL
From: Nicholas Piggin <npiggin@xxxxxxxxx>
commit a08f828cf47e6c605af21d2cdec68f84e799c318 upstream.
Similar to the syscall return path, in fast_exception_return we may be
returning to user or kernel context. We already have a test for that,
because we conditionally restore r13. So use that existing test and
branch, and bifurcate the return based on that.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/entry_64.S | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -891,7 +891,7 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ACCOUNT_CPU_USER_EXIT(r2, r4)
REST_GPR(13, r1)
-1:
+
mtspr SPRN_SRR1,r3
ld r2,_CCR(r1)
@@ -904,8 +904,22 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r3,GPR3(r1)
ld r4,GPR4(r1)
ld r1,GPR1(r1)
+ RFI_TO_USER
+ b . /* prevent speculative execution */
- rfid
+1: mtspr SPRN_SRR1,r3
+
+ ld r2,_CCR(r1)
+ mtcrf 0xFF,r2
+ ld r2,_NIP(r1)
+ mtspr SPRN_SRR0,r2
+
+ ld r0,GPR0(r1)
+ ld r2,GPR2(r1)
+ ld r3,GPR3(r1)
+ ld r4,GPR4(r1)
+ ld r1,GPR1(r1)
+ RFI_TO_KERNEL
b . /* prevent speculative execution */
#endif /* CONFIG_PPC_BOOK3E */
Patches currently in stable-queue which might be from npiggin@xxxxxxxxx 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