powerpc: Use names rather than numbers for SPRGs (v2)
The kernel uses SPRG registers for various purposes, typically in
low level assembly code as scratch registers or to hold per-cpu
global infos such as the PACA or the current thread_info pointer.
We want to be able to easily shuffle the usage of those registers
as some implementations have specific constraints realted to some
of them, for example, some have userspace readable aliases, etc..
and the current choice isn't always the best.
This patch should not change any code generation, and replaces the
usage of SPRN_SPRGn everywhere in the kernel with a named replacement
and adds documentation next to the definition of the names as to
what those are used for on each processor family.
The only parts that still use the original numbers are bits of KVM
or suspend/resume code that just blindly needs to save/restore all
the SPRGs.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index fc21329..829c3fe 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -244,8 +244,8 @@
* task's thread_struct.
*/
#define EXCEPTION_PROLOG \
- mtspr SPRN_SPRG0,r10; \
- mtspr SPRN_SPRG1,r11; \
+ mtspr SPRN_SPRG_SCRATCH0,r10; \
+ mtspr SPRN_SPRG_SCRATCH1,r11; \
mfcr r10; \
EXCEPTION_PROLOG_1; \
EXCEPTION_PROLOG_2
@@ -255,7 +255,7 @@
andi. r11,r11,MSR_PR; \
tophys(r11,r1); /* use tophys(r1) if kernel */ \
beq 1f; \
- mfspr r11,SPRN_SPRG3; \
+ mfspr r11,SPRN_SPRG_THREAD; \
lwz r11,THREAD_INFO-THREAD(r11); \
addi r11,r11,THREAD_SIZE; \
tophys(r11,r11); \
@@ -267,9 +267,9 @@
stw r10,_CCR(r11); /* save registers */ \
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
- mfspr r10,SPRN_SPRG0; \
+ mfspr r10,SPRN_SPRG_SCRATCH0; \
stw r10,GPR10(r11); \
- mfspr r12,SPRN_SPRG1; \
+ mfspr r12,SPRN_SPRG_SCRATCH1; \
stw r12,GPR11(r11); \
mflr r10; \
stw r10,_LINK(r11); \
@@ -355,11 +355,11 @@
* -- paulus.
*/
. = 0x200
- mtspr SPRN_SPRG0,r10
- mtspr SPRN_SPRG1,r11
+ mtspr SPRN_SPRG_SCRATCH0,r10
+ mtspr SPRN_SPRG_SCRATCH1,r11
mfcr r10
#ifdef CONFIG_PPC_CHRP
- mfspr r11,SPRN_SPRG2
+ mfspr r11,SPRN_SPRG_RTAS
cmpwi 0,r11,0
bne 7f
#endif /* CONFIG_PPC_CHRP */
@@ -367,7 +367,7 @@
7: EXCEPTION_PROLOG_2
addi r3,r1,STACK_FRAME_OVERHEAD
#ifdef CONFIG_PPC_CHRP
- mfspr r4,SPRN_SPRG2
+ mfspr r4,SPRN_SPRG_RTAS
cmpwi cr1,r4,0
bne cr1,1f
#endif
@@ -485,7 +485,7 @@
mfspr r3,SPRN_IMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
- mfspr r2,SPRN_SPRG3
+ mfspr r2,SPRN_SPRG_THREAD
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
lwz r2,PGDIR(r2)
bge- 112f
@@ -559,7 +559,7 @@
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
- mfspr r2,SPRN_SPRG3
+ mfspr r2,SPRN_SPRG_THREAD
li r1,_PAGE_USER|_PAGE_PRESENT /* low addresses tested as user */
lwz r2,PGDIR(r2)
bge- 112f
@@ -598,12 +598,12 @@
mtcrf 0x80,r2
BEGIN_MMU_FTR_SECTION
li r0,1
- mfspr r1,SPRN_SPRG4
+ mfspr r1,SPRN_SPRG_603_LRU
rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
slw r0,r0,r2
xor r1,r0,r1
srw r0,r1,r2
- mtspr SPRN_SPRG4,r1
+ mtspr SPRN_SPRG_603_LRU,r1
mfspr r2,SPRN_SRR1
rlwimi r2,r0,31-14,14,14
mtspr SPRN_SRR1,r2
@@ -643,7 +643,7 @@
mfspr r3,SPRN_DMISS
lis r1,PAGE_OFFSET@h /* check if kernel address */
cmplw 0,r1,r3
- mfspr r2,SPRN_SPRG3
+ mfspr r2,SPRN_SPRG_THREAD
li r1,_PAGE_RW|_PAGE_USER|_PAGE_PRESENT /* access flags */
lwz r2,PGDIR(r2)
bge- 112f
@@ -678,12 +678,12 @@
mtcrf 0x80,r2
BEGIN_MMU_FTR_SECTION
li r0,1
- mfspr r1,SPRN_SPRG4
+ mfspr r1,SPRN_SPRG_603_LRU
rlwinm r2,r3,20,27,31 /* Get Address bits 15:19 */
slw r0,r0,r2
xor r1,r0,r1
srw r0,r1,r2
- mtspr SPRN_SPRG4,r1
+ mtspr SPRN_SPRG_603_LRU,r1
mfspr r2,SPRN_SRR1
rlwimi r2,r0,31-14,14,14
mtspr SPRN_SRR1,r2
@@ -864,9 +864,9 @@
tophys(r4,r2)
addi r4,r4,THREAD /* phys address of our thread_struct */
CLR_TOP32(r4)
- mtspr SPRN_SPRG3,r4
+ mtspr SPRN_SPRG_THREAD,r4
li r3,0
- mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
+ mtspr SPRN_SPRG_RTAS,r3 /* 0 => not in RTAS */
/* enable MMU and jump to start_secondary */
li r4,MSR_KERNEL
@@ -947,9 +947,9 @@
tophys(r4,r2)
addi r4,r4,THREAD /* init task's THREAD */
CLR_TOP32(r4)
- mtspr SPRN_SPRG3,r4
+ mtspr SPRN_SPRG_THREAD,r4
li r3,0
- mtspr SPRN_SPRG2,r3 /* 0 => not in RTAS */
+ mtspr SPRN_SPRG_RTAS,r3 /* 0 => not in RTAS */
/* stack */
lis r1,init_thread_union@ha