lkml.org 
[lkml]   [2018]   [Jan]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.14 11/89] powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

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

\
 
 \ /
  Last update: 2018-01-22 10:21    [W:0.222 / U:13.500 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site