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_booke.h b/arch/powerpc/kernel/head_booke.h
index 5f9febc..50504ae 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -20,14 +20,14 @@
#endif
#define NORMAL_EXCEPTION_PROLOG \
- mtspr SPRN_SPRG0,r10; /* save two registers to work with */\
- mtspr SPRN_SPRG1,r11; \
- mtspr SPRN_SPRG4W,r1; \
+ mtspr SPRN_SPRG_WSCRATCH0,r10;/* save two registers to work with */\
+ mtspr SPRN_SPRG_WSCRATCH1,r11; \
+ mtspr SPRN_SPRG_WSCRATCH2,r1; \
mfcr r10; /* save CR in r10 for now */\
mfspr r11,SPRN_SRR1; /* check whether user or kernel */\
andi. r11,r11,MSR_PR; \
beq 1f; \
- mfspr r1,SPRN_SPRG3; /* if from user, start at top of */\
+ mfspr r1,SPRN_SPRG_THREAD; /* if from user, start at top of */\
lwz r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack */\
ALLOC_STACK_FRAME(r1, THREAD_SIZE); \
1: subi r1,r1,INT_FRAME_SIZE; /* Allocate an exception frame */\
@@ -35,13 +35,13 @@
stw r10,_CCR(r11); /* save various registers */\
stw r12,GPR12(r11); \
stw r9,GPR9(r11); \
- mfspr r10,SPRN_SPRG0; \
+ mfspr r10,SPRN_SPRG_RSCRATCH0; \
stw r10,GPR10(r11); \
- mfspr r12,SPRN_SPRG1; \
+ mfspr r12,SPRN_SPRG_RSCRATCH1; \
stw r12,GPR11(r11); \
mflr r10; \
stw r10,_LINK(r11); \
- mfspr r10,SPRN_SPRG4R; \
+ mfspr r10,SPRN_SPRG_RSCRATCH2; \
mfspr r12,SPRN_SRR0; \
stw r10,GPR1(r11); \
mfspr r9,SPRN_SRR1; \
@@ -69,21 +69,11 @@
* providing configurations that micro-optimize space usage.
*/
-/* CRIT_SPRG only used in critical exception handling */
-#define CRIT_SPRG SPRN_SPRG2
-/* MCHECK_SPRG only used in machine check exception handling */
-#define MCHECK_SPRG SPRN_SPRG6W
-
-#define MCHECK_STACK_BASE mcheckirq_ctx
+#define MC_STACK_BASE mcheckirq_ctx
#define CRIT_STACK_BASE critirq_ctx
/* only on e500mc/e200 */
-#define DEBUG_STACK_BASE dbgirq_ctx
-#ifdef CONFIG_E200
-#define DEBUG_SPRG SPRN_SPRG6W
-#else
-#define DEBUG_SPRG SPRN_SPRG9
-#endif
+#define DBG_STACK_BASE dbgirq_ctx
#define EXC_LVL_FRAME_OVERHEAD (THREAD_SIZE - INT_FRAME_SIZE - EXC_LVL_SIZE)
@@ -110,7 +100,7 @@
* critical/machine check exception stack at low physical addresses.
*/
#define EXC_LEVEL_EXCEPTION_PROLOG(exc_level, exc_level_srr0, exc_level_srr1) \
- mtspr exc_level##_SPRG,r8; \
+ mtspr SPRN_SPRG_WSCRATCH_##exc_level,r8; \
BOOKE_LOAD_EXC_LEVEL_STACK(exc_level);/* r8 points to the exc_level stack*/ \
stw r9,GPR9(r8); /* save various registers */\
mfcr r9; /* save CR in r9 for now */\
@@ -119,7 +109,7 @@
stw r9,_CCR(r8); /* save CR on stack */\
mfspr r10,exc_level_srr1; /* check whether user or kernel */\
andi. r10,r10,MSR_PR; \
- mfspr r11,SPRN_SPRG3; /* if from user, start at top of */\
+ mfspr r11,SPRN_SPRG_THREAD; /* if from user, start at top of */\
lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
addi r11,r11,EXC_LVL_FRAME_OVERHEAD; /* allocate stack frame */\
beq 1f; \
@@ -140,7 +130,7 @@
lwz r9,TI_TASK-EXC_LVL_FRAME_OVERHEAD(r11); \
stw r9,TI_TASK-EXC_LVL_FRAME_OVERHEAD(r8); \
mr r11,r8; \
-2: mfspr r8,exc_level##_SPRG; \
+2: mfspr r8,SPRN_SPRG_RSCRATCH_##exc_level; \
stw r12,GPR12(r11); /* save various registers */\
mflr r10; \
stw r10,_LINK(r11); \
@@ -161,9 +151,9 @@
#define CRITICAL_EXCEPTION_PROLOG \
EXC_LEVEL_EXCEPTION_PROLOG(CRIT, SPRN_CSRR0, SPRN_CSRR1)
#define DEBUG_EXCEPTION_PROLOG \
- EXC_LEVEL_EXCEPTION_PROLOG(DEBUG, SPRN_DSRR0, SPRN_DSRR1)
+ EXC_LEVEL_EXCEPTION_PROLOG(DBG, SPRN_DSRR0, SPRN_DSRR1)
#define MCHECK_EXCEPTION_PROLOG \
- EXC_LEVEL_EXCEPTION_PROLOG(MCHECK, SPRN_MCSRR0, SPRN_MCSRR1)
+ EXC_LEVEL_EXCEPTION_PROLOG(MC, SPRN_MCSRR0, SPRN_MCSRR1)
/*
* Exception vectors.
@@ -282,13 +272,13 @@
mtspr SPRN_DSRR1,r9; \
lwz r9,GPR9(r11); \
lwz r12,GPR12(r11); \
- mtspr DEBUG_SPRG,r8; \
- BOOKE_LOAD_EXC_LEVEL_STACK(DEBUG); /* r8 points to the debug stack */ \
+ mtspr SPRN_SPRG_WSCRATCH_DBG,r8; \
+ BOOKE_LOAD_EXC_LEVEL_STACK(DBG); /* r8 points to the debug stack */ \
lwz r10,GPR10(r8); \
lwz r11,GPR11(r8); \
- mfspr r8,DEBUG_SPRG; \
+ mfspr r8,SPRN_SPRG_RSCRATCH_DBG; \
\
- PPC_RFDI; \
+ PPC_RFDI; \
b .; \
\
/* continue normal handling for a debug exception... */ \
@@ -335,11 +325,11 @@
mtspr SPRN_CSRR1,r9; \
lwz r9,GPR9(r11); \
lwz r12,GPR12(r11); \
- mtspr CRIT_SPRG,r8; \
+ mtspr SPRN_SPRG_WSCRATCH_CRIT,r8; \
BOOKE_LOAD_EXC_LEVEL_STACK(CRIT); /* r8 points to the debug stack */ \
lwz r10,GPR10(r8); \
lwz r11,GPR11(r8); \
- mfspr r8,CRIT_SPRG; \
+ mfspr r8,SPRN_SPRG_RSCRATCH_CRIT; \
\
rfci; \
b .; \