powerpc/booke64: Eemove mfspr srr1 duplicate in exception prolog

Refactor exception prolog to get rid of mfspr srr1 duplicate. This was
introduced by KVM integration, with DO_KVM macro logic expecting srr1 value
earlier in r11.
Reserve r11 to hold srr1's value also required at the end of the prolog and
free up r10 to serve as spare in addition macros.
For syscalls case this change does not add any performance penalty. For irq
soft-disabled case the change adds a store/load of conditional register value
to/from a paca slot. Paca slots fit in one 64-byte cache line so these
additional operations have little impact on performance.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 32 insertions, 35 deletions

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 3b1ad1ba8c48..83c20e84a4fb 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -45,10 +45,9 @@
         mfcr    r10;                    /* save CR */                       \
         mfspr   r11,SPRN_##type##_SRR1;/* what are we coming from */        \
         DO_KVM  intnum,SPRN_##type##_SRR1;    /* KVM hook */                \
+        stw     r10,PACA_EX##type+EX_CR(r13); /* save old CR in the PACA */ \
         addition;                       /* additional code for that exc. */ \
         std     r1,PACA_EX##type+EX_R1(r13); /* save old r1 in the PACA */  \
-        stw     r10,PACA_EX##type+EX_CR(r13); /* save old CR in the PACA */ \
-        mfspr   r11,SPRN_##type##_SRR1;/* what are we coming from */        \
         type##_SET_KSTACK;              /* get special stack if necessary */\
         andi.   r10,r11,MSR_PR;         /* save stack pointer */            \
         beq     1f;                     /* branch around if supervisor */   \
@@ -109,8 +108,8 @@
 #define PROLOG_ADDITION_NONE_MC(n)
 
 #define PROLOG_ADDITION_MASKABLE_GEN(n)                                     \
-        lbz     r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */      \
-        cmpwi   cr0,r11,0;              /* yes -> go out of line */         \
+        lbz     r10,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */      \
+        cmpwi   cr0,r10,0;              /* yes -> go out of line */         \
         beq     masked_interrupt_book3e_##n
 
 #define PROLOG_ADDITION_2REGS_GEN(n)                                        \
@@ -624,44 +623,42 @@ kernel_dbg_exc:
  * accordingly and if the interrupt is level sensitive, we hard disable
  */
 
+.macro masked_interrupt_book3e paca_irq full_mask
+        lbz     r10,PACAIRQHAPPENED(r13)
+        ori     r10,r10,\paca_irq
+        stb     r10,PACAIRQHAPPENED(r13)
+
+        .if \full_mask == 1
+        rldicl  r10,r11,48,1            /* clear MSR_EE */
+        rotldi  r11,r10,16
+        mtspr   SPRN_SRR1,r11
+        .endif
+
+        lwz     r11,PACA_EXGEN+EX_CR(r13)
+        mtcr    r11
+        ld      r10,PACA_EXGEN+EX_R10(r13)
+        ld      r11,PACA_EXGEN+EX_R11(r13)
+        mfspr   r13,SPRN_SPRG_GEN_SCRATCH
+        rfi
+        b       .
+.endm
+
 masked_interrupt_book3e_0x500:
-        /* XXX When adding support for EPR, use PACA_IRQ_EE_EDGE */
-        li      r11,PACA_IRQ_EE
-        b       masked_interrupt_book3e_full_mask
+        // XXX When adding support for EPR, use PACA_IRQ_EE_EDGE
+        masked_interrupt_book3e PACA_IRQ_EE 1
 
 masked_interrupt_book3e_0x900:
-        ACK_DEC(r11);
-        li      r11,PACA_IRQ_DEC
-        b       masked_interrupt_book3e_no_mask
+        ACK_DEC(r10);
+        masked_interrupt_book3e PACA_IRQ_DEC 0
+
 masked_interrupt_book3e_0x980:
-        ACK_FIT(r11);
-        li      r11,PACA_IRQ_DEC
-        b       masked_interrupt_book3e_no_mask
+        ACK_FIT(r10);
+        masked_interrupt_book3e PACA_IRQ_DEC 0
+
 masked_interrupt_book3e_0x280:
 masked_interrupt_book3e_0x2c0:
-        li      r11,PACA_IRQ_DBELL
-        b       masked_interrupt_book3e_no_mask
+        masked_interrupt_book3e PACA_IRQ_DBELL 0
 
-masked_interrupt_book3e_no_mask:
-        mtcr    r10
-        lbz     r10,PACAIRQHAPPENED(r13)
-        or      r10,r10,r11
-        stb     r10,PACAIRQHAPPENED(r13)
-        b       1f
-masked_interrupt_book3e_full_mask:
-        mtcr    r10
-        lbz     r10,PACAIRQHAPPENED(r13)
-        or      r10,r10,r11
-        stb     r10,PACAIRQHAPPENED(r13)
-        mfspr   r10,SPRN_SRR1
-        rldicl  r11,r10,48,1            /* clear MSR_EE */
-        rotldi  r10,r11,16
-        mtspr   SPRN_SRR1,r10
-1:      ld      r10,PACA_EXGEN+EX_R10(r13);
-        ld      r11,PACA_EXGEN+EX_R11(r13);
-        mfspr   r13,SPRN_SPRG_GEN_SCRATCH;
-        rfi
-        b       .
 /*
  * Called from arch_local_irq_enable when an interrupt needs
  * to be resent. r3 contains either 0x500,0x900,0x260 or 0x280