From e196d237beb5cd2f354cdf681a5c560d9d02ca93 Mon Sep 17 00:00:00 2001
From: Mitchell Horne <mhorne@FreeBSD.org>
Date: Sun, 7 Apr 2019 20:12:24 +0000
Subject: [PATCH] RISC-V: initialize pcpu slightly earlier

In certain scenarios, it is possible for PCPU data to be
accessed before it has been initialized (e.g. during printf
if the kernel was built with the TSLOG option).

Initialize the PCPU pointer for hart 0 at the beginning of
initriscv() rather than near the end.

Reviewed by:		markj
Approved by:		markj (mentor)
Differential Revision:	https://reviews.freebsd.org/D19726
---
 sys/riscv/include/pcpu.h  |  1 -
 sys/riscv/riscv/machdep.c | 22 +++++++++++-----------
 2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/sys/riscv/include/pcpu.h b/sys/riscv/include/pcpu.h
index d570a68138c5..7447d14fa777 100644
--- a/sys/riscv/include/pcpu.h
+++ b/sys/riscv/include/pcpu.h
@@ -53,7 +53,6 @@
 
 struct pcb;
 struct pcpu;
-extern struct pcpu *pcpup;
 
 static inline struct pcpu *
 get_pcpu(void)
diff --git a/sys/riscv/riscv/machdep.c b/sys/riscv/riscv/machdep.c
index d5159c72cb51..30b4ce787961 100644
--- a/sys/riscv/riscv/machdep.c
+++ b/sys/riscv/riscv/machdep.c
@@ -120,8 +120,6 @@ int64_t idcache_line_size;	/* The minimum cache line size */
 extern int *end;
 extern int *initstack_end;
 
-struct pcpu *pcpup;
-
 uintptr_t mcall_trap(uintptr_t mcause, uintptr_t* regs);
 
 uintptr_t
@@ -627,6 +625,7 @@ sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 static void
 init_proc0(vm_offset_t kstack)
 {
+	struct pcpu *pcpup;
 
 	pcpup = &__pcpu[0];
 
@@ -798,6 +797,7 @@ void
 initriscv(struct riscv_bootparams *rvbp)
 {
 	struct mem_region mem_regions[FDT_MEM_REGIONS];
+	struct pcpu *pcpup;
 	vm_offset_t rstart, rend;
 	vm_offset_t s, e;
 	int mem_regions_sz;
@@ -806,6 +806,15 @@ initriscv(struct riscv_bootparams *rvbp)
 	caddr_t kmdp;
 	int i;
 
+	/* Set the pcpu data, this is needed by pmap_bootstrap */
+	pcpup = &__pcpu[0];
+	pcpu_init(pcpup, 0, sizeof(struct pcpu));
+
+	/* Set the pcpu pointer */
+	__asm __volatile("mv gp, %0" :: "r"(pcpup));
+
+	PCPU_SET(curthread, &thread0);
+
 	/* Set the module data location */
 	lastaddr = fake_preload_metadata(rvbp);
 
@@ -849,15 +858,6 @@ initriscv(struct riscv_bootparams *rvbp)
 	}
 #endif
 
-	/* Set the pcpu data, this is needed by pmap_bootstrap */
-	pcpup = &__pcpu[0];
-	pcpu_init(pcpup, 0, sizeof(struct pcpu));
-
-	/* Set the pcpu pointer */
-	__asm __volatile("mv gp, %0" :: "r"(pcpup));
-
-	PCPU_SET(curthread, &thread0);
-
 	/* Do basic tuning, hz etc */
 	init_param1();