MMU: Implement a vestigial partition table

This implements a 1-entry partition table, so that instead of getting
the process table base address from the PRTBL SPR, the MMU now reads
the doubleword pointed to by the PTCR register plus 8 to get the
process table base address.  The partition table entry is cached.

Having the PTCR and the vestigial partition table reduces the amount
of software change required in Linux for Microwatt support.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

tests/mmu/mmu.c

@@ -24,7 +24,7 @@ static inline void do_tlbie(unsigned long rb, unsigned long rs)
 #define SRR0	26
 #define SRR1	27
 #define PID	48
-#define PRTBL	720
+#define PTCR	464
 
 static inline unsigned long mfspr(int sprnum)
 {
@@ -115,15 +115,18 @@ void zero_memory(void *ptr, unsigned long nbytes)
  */
 unsigned long *pgdir = (unsigned long *) 0x10000;
 unsigned long *proc_tbl = (unsigned long *) 0x12000;
-unsigned long free_ptr = 0x13000;
+unsigned long *part_tbl = (unsigned long *) 0x13000;
+unsigned long free_ptr = 0x14000;
 void *eas_mapped[4];
 int neas_mapped;
 
 void init_mmu(void)
 {
+	/* set up partition table */
+	store_pte(&part_tbl[1], (unsigned long)proc_tbl);
 	/* set up process table */
 	zero_memory(proc_tbl, 512 * sizeof(unsigned long));
-	mtspr(PRTBL, (unsigned long)proc_tbl);
+	mtspr(PTCR, (unsigned long)part_tbl);
 	mtspr(PID, 1);
 	zero_memory(pgdir, 1024 * sizeof(unsigned long));
 	/* RTS = 0 (2GB address space), RPDS = 10 (1024-entry top level) */

tests/modes/modes.c

@@ -33,7 +33,7 @@ static inline void do_tlbie(unsigned long rb, unsigned long rs)
 #define SPRG0	272
 #define SPRG1	273
 #define SPRG3	275
-#define PRTBL	720
+#define PTCR	464
 
 static inline unsigned long mfspr(int sprnum)
 {
@@ -121,15 +121,18 @@ void zero_memory(void *ptr, unsigned long nbytes)
  * Set up an MMU translation tree using memory starting at the 64k point.
  * We use 3 levels, mapping 512GB, with 4kB PGD/PMD/PTE pages.
  */
-unsigned long *proc_tbl = (unsigned long *) 0x10000;
-unsigned long *pgdir = (unsigned long *) 0x11000;
-unsigned long free_ptr = 0x12000;
+unsigned long *part_tbl = (unsigned long *) 0x10000;
+unsigned long *proc_tbl = (unsigned long *) 0x11000;
+unsigned long *pgdir = (unsigned long *) 0x12000;
+unsigned long free_ptr = 0x13000;
 
 void init_mmu(void)
 {
+	/* set up partition table */
+	store_pte(&part_tbl[1], (unsigned long)proc_tbl);
 	/* set up process table */
 	zero_memory(proc_tbl, 512 * sizeof(unsigned long));
-	mtspr(PRTBL, (unsigned long)proc_tbl);
+	mtspr(PTCR, (unsigned long)part_tbl);
 	mtspr(PID, 1);
 	zero_memory(pgdir, 512 * sizeof(unsigned long));
 	/* RTS = 8 (512GB address space), RPDS = 9 (512-entry top level) */

tests/privileged/privileged.c

@@ -14,7 +14,7 @@ extern int call_with_msr(unsigned long arg, int (*fn)(unsigned long), unsigned l
 #define SRR0	26
 #define SRR1	27
 #define PID	48
-#define PRTBL	720
+#define PTCR	464
 #define PVR	287
 
 static inline unsigned long mfspr(int sprnum)
@@ -106,15 +106,18 @@ void zero_memory(void *ptr, unsigned long nbytes)
  */
 unsigned long *pgdir = (unsigned long *) 0x10000;
 unsigned long *proc_tbl = (unsigned long *) 0x12000;
-unsigned long free_ptr = 0x13000;
+unsigned long *part_tbl = (unsigned long *) 0x13000;
+unsigned long free_ptr = 0x14000;
 
 void init_mmu(void)
 {
+	/* set up partition table */
+	store_pte(&part_tbl[1], (unsigned long)proc_tbl);
 	/* set up process table */
 	zero_memory(proc_tbl, 512 * sizeof(unsigned long));
 	/* RTS = 0 (2GB address space), RPDS = 10 (1024-entry top level) */
 	store_pte(&proc_tbl[2 * 1], (unsigned long) pgdir | 10);
-	mtspr(PRTBL, (unsigned long)proc_tbl);
+	mtspr(PTCR, (unsigned long)part_tbl);
 	mtspr(PID, 1);
 	zero_memory(pgdir, 1024 * sizeof(unsigned long));
 }

tests/reservation/reservation.c

@@ -18,7 +18,6 @@ extern unsigned long do_stqcx(unsigned long dst, unsigned long regs);
 #define PID	48
 #define SPRG0	272
 #define SPRG1	273
-#define PRTBL	720
 
 static inline unsigned long mfspr(int sprnum)
 {

tests/spr_read/spr_read.c

@@ -38,7 +38,7 @@ void print_test(char *str)
 #define SPR_HSPRG0	304
 #define SPR_HSPRG1	305
 #define SPR_PID		48
-#define SPR_PRTBL	720
+#define SPR_PTCR	464
 #define SPR_PVR		287
 
 #define __stringify_1(x...)	#x
@@ -83,7 +83,7 @@ int main(void)
 	DO_ONE(SPR_HSPRG0);
 	DO_ONE(SPR_HSPRG1);
 	DO_ONE(SPR_PID);
-	DO_ONE(SPR_PRTBL);
+	DO_ONE(SPR_PTCR);
 	DO_ONE(SPR_PVR);
 
 	puts(PASS);

tests/test_spr_read.console_out

@@ -20,6 +20,6 @@ Test SPR_SPRG3U:PASS
 Test SPR_HSPRG0:PASS
 Test SPR_HSPRG1:PASS
 Test SPR_PID:PASS
-Test SPR_PRTBL:PASS
+Test SPR_PTCR:PASS
 Test SPR_PVR:PASS
 PASS