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/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 72644cf..4e9640c 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -24,18 +24,6 @@
* 0x8000 - : Early init and support code
*/
-
-/*
- * SPRG Usage
- *
- * Register Definition
- *
- * SPRG0 reserved for hypervisor
- * SPRG1 temp - used to save gpr
- * SPRG2 temp - used to save gpr
- * SPRG3 virt addr of paca
- */
-
/*
* This is the start of the interrupt handlers for pSeries
* This code runs with relocation off.
@@ -53,16 +41,16 @@
. = 0x200
_machine_check_pSeries:
HMT_MEDIUM
- mtspr SPRN_SPRG1,r13 /* save r13 */
+ mtspr SPRN_SPRG_SCRATCH0,r13 /* save r13 */
EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
. = 0x300
.globl data_access_pSeries
data_access_pSeries:
HMT_MEDIUM
- mtspr SPRN_SPRG1,r13
+ mtspr SPRN_SPRG_SCRATCH0,r13
BEGIN_FTR_SECTION
- mtspr SPRN_SPRG2,r12
+ mtspr SPRN_SPRG_SCRATCH1,r12
mfspr r13,SPRN_DAR
mfspr r12,SPRN_DSISR
srdi r13,r13,60
@@ -71,7 +59,7 @@
cmpwi r13,0x2c
beq do_stab_bolted_pSeries
mtcrf 0x80,r12
- mfspr r12,SPRN_SPRG2
+ mfspr r12,SPRN_SPRG_SCRATCH1
END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, data_access_common)
@@ -79,8 +67,8 @@
.globl data_access_slb_pSeries
data_access_slb_pSeries:
HMT_MEDIUM
- mtspr SPRN_SPRG1,r13
- mfspr r13,SPRN_SPRG3 /* get paca address into r13 */
+ mtspr SPRN_SPRG_SCRATCH0,r13
+ mfspr r13,SPRN_SPRG_PACA /* get paca address into r13 */
std r3,PACA_EXSLB+EX_R3(r13)
mfspr r3,SPRN_DAR
std r9,PACA_EXSLB+EX_R9(r13) /* save r9 - r12 */
@@ -93,7 +81,7 @@
std r10,PACA_EXSLB+EX_R10(r13)
std r11,PACA_EXSLB+EX_R11(r13)
std r12,PACA_EXSLB+EX_R12(r13)
- mfspr r10,SPRN_SPRG1
+ mfspr r10,SPRN_SPRG_SCRATCH0
std r10,PACA_EXSLB+EX_R13(r13)
mfspr r12,SPRN_SRR1 /* and SRR1 */
#ifndef CONFIG_RELOCATABLE
@@ -117,8 +105,8 @@
.globl instruction_access_slb_pSeries
instruction_access_slb_pSeries:
HMT_MEDIUM
- mtspr SPRN_SPRG1,r13
- mfspr r13,SPRN_SPRG3 /* get paca address into r13 */
+ mtspr SPRN_SPRG_SCRATCH0,r13
+ mfspr r13,SPRN_SPRG_PACA /* get paca address into r13 */
std r3,PACA_EXSLB+EX_R3(r13)
mfspr r3,SPRN_SRR0 /* SRR0 is faulting address */
std r9,PACA_EXSLB+EX_R9(r13) /* save r9 - r12 */
@@ -131,7 +119,7 @@
std r10,PACA_EXSLB+EX_R10(r13)
std r11,PACA_EXSLB+EX_R11(r13)
std r12,PACA_EXSLB+EX_R12(r13)
- mfspr r10,SPRN_SPRG1
+ mfspr r10,SPRN_SPRG_SCRATCH0
std r10,PACA_EXSLB+EX_R13(r13)
mfspr r12,SPRN_SRR1 /* and SRR1 */
#ifndef CONFIG_RELOCATABLE
@@ -161,7 +149,7 @@
beq- 1f
END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE)
mr r9,r13
- mfspr r13,SPRN_SPRG3
+ mfspr r13,SPRN_SPRG_PACA
mfspr r11,SPRN_SRR0
ld r12,PACAKBASE(r13)
ld r10,PACAKMSR(r13)
@@ -230,14 +218,14 @@
rotldi r10,r10,16
mtspr SPRN_SRR1,r10
ld r10,PACA_EXGEN+EX_R10(r13)
- mfspr r13,SPRN_SPRG1
+ mfspr r13,SPRN_SPRG_SCRATCH0
rfid
b .
.align 7
do_stab_bolted_pSeries:
mtcrf 0x80,r12
- mfspr r12,SPRN_SPRG2
+ mfspr r12,SPRN_SPRG_SCRATCH1
EXCEPTION_PROLOG_PSERIES(PACA_EXSLB, .do_stab_bolted)
#ifdef CONFIG_PPC_PSERIES
@@ -248,14 +236,14 @@
.align 7
system_reset_fwnmi:
HMT_MEDIUM
- mtspr SPRN_SPRG1,r13 /* save r13 */
+ mtspr SPRN_SPRG_SCRATCH0,r13 /* save r13 */
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common)
.globl machine_check_fwnmi
.align 7
machine_check_fwnmi:
HMT_MEDIUM
- mtspr SPRN_SPRG1,r13 /* save r13 */
+ mtspr SPRN_SPRG_SCRATCH0,r13 /* save r13 */
EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
#endif /* CONFIG_PPC_PSERIES */
@@ -270,7 +258,7 @@
std r10,PACA_EXGEN+EX_R10(r13)
std r11,PACA_EXGEN+EX_R11(r13)
std r12,PACA_EXGEN+EX_R12(r13)
- mfspr r10,SPRG1
+ mfspr r10,SPRG_SCRATCH0
ld r11,PACA_EXSLB+EX_R9(r13)
ld r12,PACA_EXSLB+EX_R3(r13)
std r10,PACA_EXGEN+EX_R13(r13)