[PATCH 2/7] powerpc/8xx: Remove macro that checks kernel address

From: Christophe Leroy
Date: Wed Jul 12 2017 - 06:09:09 EST


The macro to check if an address is a kernel address or not is
not used anymore in DTLBmiss handler. It is used in ITLB miss handler
and in DTLB error handler. DTLB error handler is not a hot path, it
doesn't need such optimisation.

In order to simplify a following patch which will rework ITLB miss
handler, we remove the macros and reintroduce them inside the handler.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/head_8xx.S | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c032fe8c2d26..02671e33905c 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -50,16 +50,9 @@
mtspr spr, reg
#endif

-/* Macro to test if an address is a kernel address */
#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000
-#define IS_KERNEL(tmp, addr) \
- andis. tmp, addr, 0x8000 /* Address >= 0x80000000 */
-#define BRANCH_UNLESS_KERNEL(label) beq label
-#else
-#define IS_KERNEL(tmp, addr) \
- rlwinm tmp, addr, 16, 16, 31; \
- cmpli cr0, tmp, PAGE_OFFSET >> 16
-#define BRANCH_UNLESS_KERNEL(label) blt label
+/* By simply checking Address >= 0x80000000, we know if its a kernel address */
+#define SIMPLE_KERNEL_ADDRESS 1
#endif


@@ -347,11 +340,20 @@ InstructionTLBMiss:
mfcr r3
#endif
#if defined(CONFIG_MODULES) || defined (CONFIG_DEBUG_PAGEALLOC)
- IS_KERNEL(r11, r10)
+#ifdef SIMPLE_KERNEL_ADDRESS
+ andis. r11, r10, 0x8000 /* Address >= 0x80000000 */
+#else
+ rlwinm r11, r10, 16, 0xfff8
+ cmpli cr0, r11, PAGE_OFFSET@h
+#endif
#endif
mfspr r11, SPRN_M_TW /* Get level 1 table */
#if defined(CONFIG_MODULES) || defined (CONFIG_DEBUG_PAGEALLOC)
- BRANCH_UNLESS_KERNEL(3f)
+#ifdef SIMPLE_KERNEL_ADDRESS
+ beq+ 3f
+#else
+ blt+ 3f
+#endif
lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha
3:
#endif
@@ -705,9 +707,10 @@ FixupDAR:/* Entry point for dcbx workaround. */
mtspr SPRN_SPRG_SCRATCH2, r10
/* fetch instruction from memory. */
mfspr r10, SPRN_SRR0
- IS_KERNEL(r11, r10)
+ rlwinm r11, r10, 16, 0xfff8
+ cmpli cr0, r11, PAGE_OFFSET@h
mfspr r11, SPRN_M_TW /* Get level 1 table */
- BRANCH_UNLESS_KERNEL(3f)
+ blt+ 3f
rlwinm r11, r10, 16, 0xfff8
_ENTRY(FixupDAR_cmp)
cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h
--
2.12.0