svn commit: r361859 - in head/sys/powerpc: aim include powerpc

[Justin Hibbits]

Author: jhibbits
Date: Sat Jun  6 02:40:52 2020
New Revision: 361859
URL: https://svnweb.freebsd.org/changeset/base/361859

Log:
  powerpc: Add a (CPU/runtime features) flags set to pcpu struct
  
  Summary:
  The point of this addition is to cache CPU behavior 'features', to avoid
  having to recompute based on CPU, etc.
  
  The first such use case is to avoid the unnecessary manipulation of the
  SLBs (Segment Lookaside Buffers) when using the Radix pmap on POWER9.
  Since we already get the PCPU pointer wherever we swap the SLB entries,
  we can use a cached flag to check if it's necessary to perform the
  operation anyway, and skip it when not.
  
  Reviewed by:	bdragon
  Differential Revision:	https://reviews.freebsd.org/D24908

Modified:
  head/sys/powerpc/aim/mmu_radix.c
  head/sys/powerpc/aim/trap_subr64.S
  head/sys/powerpc/include/pcpu.h
  head/sys/powerpc/powerpc/db_interface.c
  head/sys/powerpc/powerpc/genassym.c
  head/sys/powerpc/powerpc/mp_machdep.c

Modified: head/sys/powerpc/aim/mmu_radix.c
==============================================================================
--- head/sys/powerpc/aim/mmu_radix.c	Sat Jun  6 02:28:21 2020	(r361858)
+++ head/sys/powerpc/aim/mmu_radix.c	Sat Jun  6 02:40:52 2020	(r361859)
@@ -2327,6 +2327,7 @@ mmu_radix_bootstrap(vm_offset_t start, vm_offset_t end
 		printf("%s done\n", __func__);
 	pmap_bootstrapped = 1;
 	dmaplimit = roundup2(powerpc_ptob(Maxmem), L2_PAGE_SIZE);
+	PCPU_SET(flags, PCPU_GET(flags) | PC_FLAG_NOSRS);
 }
 
 static void

Modified: head/sys/powerpc/aim/trap_subr64.S
==============================================================================
--- head/sys/powerpc/aim/trap_subr64.S	Sat Jun  6 02:28:21 2020	(r361858)
+++ head/sys/powerpc/aim/trap_subr64.S	Sat Jun  6 02:40:52 2020	(r361859)
@@ -87,6 +87,9 @@ restore_usersrs:
  */
 restore_kernsrs:
 	GET_CPUINFO(%r28)
+	lwz	%r29, PC_FLAGS(%r28)
+	mtcr	%r29
+	btlr	0
 	addi	%r28,%r28,PC_KERNSLB
 	ld	%r29,16(%r28)		/* One past USER_SLB_SLOT */
 	cmpdi	%r29,0
@@ -270,9 +273,13 @@ restore_kernsrs:
 	std	%r29,(savearea+CPUSAVE_R29)(%r3);			\
 	std	%r30,(savearea+CPUSAVE_R30)(%r3);			\
 	std	%r31,(savearea+CPUSAVE_R31)(%r3);			\
+	lwz	%r28,PC_FLAGS(%r3);					\
+	mtcr	%r28;							\
+	bt	0, 0f;	/* Check to skip restoring SRs. */		\
 	mflr	%r27;			/* preserve LR */		\
 	bl	restore_usersrs;	/* uses r28-r31 */		\
 	mtlr	%r27;							\
+0:									\
 	ld	%r31,(savearea+CPUSAVE_R31)(%r3);			\
 	ld	%r30,(savearea+CPUSAVE_R30)(%r3);			\
 	ld	%r29,(savearea+CPUSAVE_R29)(%r3);			\

Modified: head/sys/powerpc/include/pcpu.h
==============================================================================
--- head/sys/powerpc/include/pcpu.h	Sat Jun  6 02:28:21 2020	(r361858)
+++ head/sys/powerpc/include/pcpu.h	Sat Jun  6 02:40:52 2020	(r361859)
@@ -50,6 +50,7 @@ struct pvo_entry;
 	int		pc_bsp;						\
 	volatile int	pc_awake;					\
 	uint32_t	pc_ipimask;					\
+	uint32_t	pc_flags;		/* cpu feature flags */ \
 	register_t	pc_tempsave[CPUSAVE_LEN];			\
 	register_t	pc_disisave[CPUSAVE_LEN];			\
 	register_t	pc_dbsave[CPUSAVE_LEN];				\
@@ -76,6 +77,9 @@ struct pvo_entry;
 #else
 #define PCPU_MD_AIM_FIELDS	PCPU_MD_AIM32_FIELDS
 #endif
+
+/* CPU feature flags, can be used for cached flow control. */
+#define	PC_FLAG_NOSRS		0x80000000
 
 #define	BOOKE_CRITSAVE_LEN	(CPUSAVE_LEN + 2)
 #define	BOOKE_TLB_MAXNEST	4

Modified: head/sys/powerpc/powerpc/db_interface.c
==============================================================================
--- head/sys/powerpc/powerpc/db_interface.c	Sat Jun  6 02:28:21 2020	(r361858)
+++ head/sys/powerpc/powerpc/db_interface.c	Sat Jun  6 02:40:52 2020	(r361859)
@@ -91,4 +91,5 @@ db_show_mdpcpu(struct pcpu *pc)
 
 	db_printf("PPC: hwref   = %#zx\n", pc->pc_hwref);
 	db_printf("PPC: ipimask = %#x\n", pc->pc_ipimask);
+	db_printf("PPC: flags   = %#x\n", pc->pc_flags);
 }

Modified: head/sys/powerpc/powerpc/genassym.c
==============================================================================
--- head/sys/powerpc/powerpc/genassym.c	Sat Jun  6 02:28:21 2020	(r361858)
+++ head/sys/powerpc/powerpc/genassym.c	Sat Jun  6 02:40:52 2020	(r361859)
@@ -64,6 +64,7 @@ ASSYM(PC_TEMPSAVE, offsetof(struct pcpu, pc_tempsave))
 ASSYM(PC_DISISAVE, offsetof(struct pcpu, pc_disisave));
 ASSYM(PC_DBSAVE, offsetof(struct pcpu, pc_dbsave));
 ASSYM(PC_RESTORE, offsetof(struct pcpu, pc_restore));
+ASSYM(PC_FLAGS, offsetof(struct pcpu, pc_flags));
 
 #if defined(BOOKE)
 ASSYM(PC_BOOKE_CRITSAVE, offsetof(struct pcpu, pc_booke.critsave));
@@ -106,6 +107,7 @@ ASSYM(TLBSAVE_BOOKE_R31, TLBSAVE_BOOKE_R31*sizeof(regi
 
 ASSYM(MTX_LOCK, offsetof(struct mtx, mtx_lock));
 
+ASSYM(PC_FLAG_NOSRS, PC_FLAG_NOSRS);
 #if defined(AIM)
 ASSYM(USER_ADDR, USER_ADDR);
 #ifdef __powerpc64__

Modified: head/sys/powerpc/powerpc/mp_machdep.c
==============================================================================
--- head/sys/powerpc/powerpc/mp_machdep.c	Sat Jun  6 02:28:21 2020	(r361858)
+++ head/sys/powerpc/powerpc/mp_machdep.c	Sat Jun  6 02:40:52 2020	(r361859)
@@ -246,6 +246,7 @@ cpu_mp_unleash(void *dummy)
 				printf("Waking up CPU %d (dev=%x)\n",
 				    pc->pc_cpuid, (int)pc->pc_hwref);
 
+			pc->pc_flags = PCPU_GET(flags); /* Copy cached CPU flags */
 			ret = platform_smp_start_cpu(pc);
 			if (ret == 0) {
 				timeout = 2000;	/* wait 2sec for the AP */