powerpc/64s: SLB miss already has CTR saved for relocatable kernel

The EXCEPTION_PROLOG_1 used by SLB miss already saves CTR when the
kernel is built with CONFIG_RELOCATABLE. So it does not have to be
saved and reloaded when branching to slb_miss_realmode. It can be
restored from the PACA as usual.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index fe3bc52aadf88f42e7b0d648295c82091a3772fb..059b3a3562505bac8506d48f1ded1d8c09444471 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -522,7 +522,6 @@ EXC_REAL_BEGIN(data_access_slb, 0x380, 0x80)
         * because the distance from here to there depends on where
         * the kernel ends up being put.
         */
-       mfctr   r11
        LOAD_HANDLER(r10, slb_miss_realmode)
        mtctr   r10
        bctr
@@ -545,7 +544,6 @@ EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80)
         * because the distance from here to there depends on where
         * the kernel ends up being put.
         */
-       mfctr   r11
        LOAD_HANDLER(r10, slb_miss_realmode)
        mtctr   r10
        bctr
@@ -585,7 +583,6 @@ EXC_REAL_BEGIN(instruction_access_slb, 0x480, 0x80)
 #ifndef CONFIG_RELOCATABLE
        b       slb_miss_realmode
 #else
-       mfctr   r11
        LOAD_HANDLER(r10, slb_miss_realmode)
        mtctr   r10
        bctr
@@ -603,7 +600,6 @@ EXC_VIRT_BEGIN(instruction_access_slb, 0x4480, 0x80)
 #ifndef CONFIG_RELOCATABLE
        b       slb_miss_realmode
 #else
-       mfctr   r11
        LOAD_HANDLER(r10, slb_miss_realmode)
        mtctr   r10
        bctr
@@ -625,10 +621,6 @@ EXC_COMMON_BEGIN(slb_miss_realmode)
         * procedure.
         */
        mflr    r10
-#ifdef CONFIG_RELOCATABLE
-       mtctr   r11
-#endif
-
        stw     r9,PACA_EXSLB+EX_CCR(r13)       /* save CR in exc. frame */
        std     r10,PACA_EXSLB+EX_LR(r13)       /* save LR */
 
@@ -657,6 +649,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
        mtcrf   0x01,r9         /* slb_allocate uses cr0 and cr7 */
 .machine       pop
 
+       RESTORE_CTR(r9, PACA_EXSLB)
        RESTORE_PPR_PACA(PACA_EXSLB, r9)
        ld      r3,PACA_EXSLB+EX_R3(r13)
        ld      r9,PACA_EXSLB+EX_R9(r13)