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authorNicholas Piggin <npiggin@gmail.com>2018-01-10 03:07:15 +1100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-13 12:35:54 +0100
commit9d914324d966497f4d40cfa9333cbe55150cc09b (patch)
treeea536fd5773261a10b4541e52aceb7c4e5f64f31 /arch/powerpc
parent8fd3f98d0f4d5a9044b900de950ab02164968d27 (diff)
powerpc/64: Convert fast_exception_return to use RFI_TO_USER/KERNEL
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@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/entry_64.S18
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index caa659671599..d267d3bcde90 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -859,7 +859,7 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ACCOUNT_CPU_USER_EXIT(r13, r2, r4)
REST_GPR(13, r1)
-1:
+
mtspr SPRN_SRR1,r3
ld r2,_CCR(r1)
@@ -872,8 +872,22 @@ 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 */