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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
commit48cc95d4e4d6a1265b7f728182d6dc62de849b05 (patch)
tree014db611b6bdaa1e46b59ca89f0085e5a7462adc /arch/powerpc/kernel
parent00e40620a51ebee4ea002ec2efcd64f1960cb964 (diff)
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powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL
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>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/exceptions-64s.S22
1 files changed, 20 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index fd68e19b9ef7..fc72f81411c4 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -655,6 +655,8 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
andi. r10,r12,MSR_RI /* check for unrecoverable exception */
beq- 2f
+ andi. r10,r12,MSR_PR /* check for user mode (PR != 0) */
+ bne 1f
/* All done -- return from exception. */
@@ -671,7 +673,23 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
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
@@ -679,7 +697,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
mtspr SPRN_SRR0,r10
ld r10,PACAKMSR(r13)
mtspr SPRN_SRR1,r10
- rfid
+ RFI_TO_KERNEL
b .
8: mfspr r11,SPRN_SRR0