16 files changed, 432 insertions, 195 deletions

diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index e1274fc03af4..f13f7f276639 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -31,6 +31,7 @@ obj-y	+= vdso/
 
 CFLAGS_setup.o := -mcmodel=medany
 
+obj-$(CONFIG_FPU)		+= fpu.o
 obj-$(CONFIG_SMP)		+= smpboot.o
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_MODULES)		+= module.o
diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
index 0bc86e5f8f3f..cb35ffd8ec6b 100644
--- a/arch/riscv/kernel/cacheinfo.c
+++ b/arch/riscv/kernel/cacheinfo.c
@@ -22,13 +22,6 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
 {
 	this_leaf->level = level;
 	this_leaf->type = type;
-	/* not a sector cache */
-	this_leaf->physical_line_partition = 1;
-	/* TODO: Add to DTS */
-	this_leaf->attributes =
-		CACHE_WRITE_BACK
-		| CACHE_READ_ALLOCATE
-		| CACHE_WRITE_ALLOCATE;
 }
 
 static int __init_cache_level(unsigned int cpu)
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index ca6c81e54e37..3a5a2ee31547 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -14,9 +14,13 @@
 #include <linux/init.h>
 #include <linux/seq_file.h>
 #include <linux/of.h>
+#include <asm/smp.h>
 
-/* Return -1 if not a valid hart */
-int riscv_of_processor_hart(struct device_node *node)
+/*
+ * Returns the hart ID of the given device tree node, or -1 if the device tree
+ * node isn't a RISC-V hart.
+ */
+int riscv_of_processor_hartid(struct device_node *node)
 {
 	const char *isa, *status;
 	u32 hart;
@@ -58,6 +62,64 @@ int riscv_of_processor_hart(struct device_node *node)
 
 #ifdef CONFIG_PROC_FS
 
+static void print_isa(struct seq_file *f, const char *orig_isa)
+{
+	static const char *ext = "mafdc";
+	const char *isa = orig_isa;
+	const char *e;
+
+	/*
+	 * Linux doesn't support rv32e or rv128i, and we only support booting
+	 * kernels on harts with the same ISA that the kernel is compiled for.
+	 */
+#if defined(CONFIG_32BIT)
+	if (strncmp(isa, "rv32i", 5) != 0)
+		return;
+#elif defined(CONFIG_64BIT)
+	if (strncmp(isa, "rv64i", 5) != 0)
+		return;
+#endif
+
+	/* Print the base ISA, as we already know it's legal. */
+	seq_puts(f, "isa\t\t: ");
+	seq_write(f, isa, 5);
+	isa += 5;
+
+	/*
+	 * Check the rest of the ISA string for valid extensions, printing those
+	 * we find.  RISC-V ISA strings define an order, so we only print the
+	 * extension bits when they're in order.
+	 */
+	for (e = ext; *e != '\0'; ++e) {
+		if (isa[0] == e[0]) {
+			seq_write(f, isa, 1);
+			isa++;
+		}
+	}
+	seq_puts(f, "\n");
+
+	/*
+	 * If we were given an unsupported ISA in the device tree then print
+	 * a bit of info describing what went wrong.
+	 */
+	if (isa[0] != '\0')
+		pr_info("unsupported ISA \"%s\" in device tree", orig_isa);
+}
+
+static void print_mmu(struct seq_file *f, const char *mmu_type)
+{
+#if defined(CONFIG_32BIT)
+	if (strcmp(mmu_type, "riscv,sv32") != 0)
+		return;
+#elif defined(CONFIG_64BIT)
+	if (strcmp(mmu_type, "riscv,sv39") != 0 &&
+	    strcmp(mmu_type, "riscv,sv48") != 0)
+		return;
+#endif
+
+	seq_printf(f, "mmu\t\t: %s\n", mmu_type+6);
+}
+
 static void *c_start(struct seq_file *m, loff_t *pos)
 {
 	*pos = cpumask_next(*pos - 1, cpu_online_mask);
@@ -78,21 +140,20 @@ static void c_stop(struct seq_file *m, void *v)
 
 static int c_show(struct seq_file *m, void *v)
 {
-	unsigned long hart_id = (unsigned long)v - 1;
-	struct device_node *node = of_get_cpu_node(hart_id, NULL);
+	unsigned long cpu_id = (unsigned long)v - 1;
+	struct device_node *node = of_get_cpu_node(cpuid_to_hartid_map(cpu_id),
+						   NULL);
 	const char *compat, *isa, *mmu;
 
-	seq_printf(m, "hart\t: %lu\n", hart_id);
-	if (!of_property_read_string(node, "riscv,isa", &isa)
-	    && isa[0] == 'r'
-	    && isa[1] == 'v')
-		seq_printf(m, "isa\t: %s\n", isa);
-	if (!of_property_read_string(node, "mmu-type", &mmu)
-	    && !strncmp(mmu, "riscv,", 6))
-		seq_printf(m, "mmu\t: %s\n", mmu+6);
+	seq_printf(m, "processor\t: %lu\n", cpu_id);
+	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
+	if (!of_property_read_string(node, "riscv,isa", &isa))
+		print_isa(m, isa);
+	if (!of_property_read_string(node, "mmu-type", &mmu))
+		print_mmu(m, mmu);
 	if (!of_property_read_string(node, "compatible", &compat)
 	    && strcmp(compat, "riscv"))
-		seq_printf(m, "uarch\t: %s\n", compat);
+		seq_printf(m, "uarch\t\t: %s\n", compat);
 	seq_puts(m, "\n");
 
 	return 0;
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 17011a870044..0339087aa652 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -22,10 +22,13 @@
 #include <asm/hwcap.h>
 
 unsigned long elf_hwcap __read_mostly;
+#ifdef CONFIG_FPU
+bool has_fpu __read_mostly;
+#endif
 
 void riscv_fill_hwcap(void)
 {
-	struct device_node *node;
+	struct device_node *node = NULL;
 	const char *isa;
 	size_t i;
 	static unsigned long isa2hwcap[256] = {0};
@@ -41,9 +44,11 @@ void riscv_fill_hwcap(void)
 
 	/*
 	 * We don't support running Linux on hertergenous ISA systems.  For
-	 * now, we just check the ISA of the first processor.
+	 * now, we just check the ISA of the first "okay" processor.
 	 */
-	node = of_find_node_by_type(NULL, "cpu");
+	while ((node = of_find_node_by_type(node, "cpu")))
+		if (riscv_of_processor_hartid(node) >= 0)
+			break;
 	if (!node) {
 		pr_warning("Unable to find \"cpu\" devicetree entry");
 		return;
@@ -57,5 +62,17 @@ void riscv_fill_hwcap(void)
 	for (i = 0; i < strlen(isa); ++i)
 		elf_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
 
+	/* We don't support systems with F but without D, so mask those out
+	 * here. */
+	if ((elf_hwcap & COMPAT_HWCAP_ISA_F) && !(elf_hwcap & COMPAT_HWCAP_ISA_D)) {
+		pr_info("This kernel does not support systems with F but not D");
+		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
+	}
+
 	pr_info("elf_hwcap is 0x%lx", elf_hwcap);
+
+#ifdef CONFIG_FPU
+	if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
+		has_fpu = true;
+#endif
 }
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index fa2c08e3c05e..13d4826ab2a1 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -168,7 +168,6 @@ ENTRY(handle_exception)
 
 	/* Handle interrupts */
 	move a0, sp /* pt_regs */
-	move a1, s4 /* scause */
 	tail do_IRQ
 1:
 	/* Exceptions run with interrupts enabled */
@@ -357,93 +356,6 @@ ENTRY(__switch_to)
 	ret
 ENDPROC(__switch_to)
 
-ENTRY(__fstate_save)
-	li  a2,  TASK_THREAD_F0
-	add a0, a0, a2
-	li t1, SR_FS
-	csrs sstatus, t1
-	frcsr t0
-	fsd f0,  TASK_THREAD_F0_F0(a0)
-	fsd f1,  TASK_THREAD_F1_F0(a0)
-	fsd f2,  TASK_THREAD_F2_F0(a0)
-	fsd f3,  TASK_THREAD_F3_F0(a0)
-	fsd f4,  TASK_THREAD_F4_F0(a0)
-	fsd f5,  TASK_THREAD_F5_F0(a0)
-	fsd f6,  TASK_THREAD_F6_F0(a0)
-	fsd f7,  TASK_THREAD_F7_F0(a0)
-	fsd f8,  TASK_THREAD_F8_F0(a0)
-	fsd f9,  TASK_THREAD_F9_F0(a0)
-	fsd f10, TASK_THREAD_F10_F0(a0)
-	fsd f11, TASK_THREAD_F11_F0(a0)
-	fsd f12, TASK_THREAD_F12_F0(a0)
-	fsd f13, TASK_THREAD_F13_F0(a0)
-	fsd f14, TASK_THREAD_F14_F0(a0)
-	fsd f15, TASK_THREAD_F15_F0(a0)
-	fsd f16, TASK_THREAD_F16_F0(a0)
-	fsd f17, TASK_THREAD_F17_F0(a0)
-	fsd f18, TASK_THREAD_F18_F0(a0)
-	fsd f19, TASK_THREAD_F19_F0(a0)
-	fsd f20, TASK_THREAD_F20_F0(a0)
-	fsd f21, TASK_THREAD_F21_F0(a0)
-	fsd f22, TASK_THREAD_F22_F0(a0)
-	fsd f23, TASK_THREAD_F23_F0(a0)
-	fsd f24, TASK_THREAD_F24_F0(a0)
-	fsd f25, TASK_THREAD_F25_F0(a0)
-	fsd f26, TASK_THREAD_F26_F0(a0)
-	fsd f27, TASK_THREAD_F27_F0(a0)
-	fsd f28, TASK_THREAD_F28_F0(a0)
-	fsd f29, TASK_THREAD_F29_F0(a0)
-	fsd f30, TASK_THREAD_F30_F0(a0)
-	fsd f31, TASK_THREAD_F31_F0(a0)
-	sw t0, TASK_THREAD_FCSR_F0(a0)
-	csrc sstatus, t1
-	ret
-ENDPROC(__fstate_save)
-
-ENTRY(__fstate_restore)
-	li  a2,  TASK_THREAD_F0
-	add a0, a0, a2
-	li t1, SR_FS
-	lw t0, TASK_THREAD_FCSR_F0(a0)
-	csrs sstatus, t1
-	fld f0,  TASK_THREAD_F0_F0(a0)
-	fld f1,  TASK_THREAD_F1_F0(a0)
-	fld f2,  TASK_THREAD_F2_F0(a0)
-	fld f3,  TASK_THREAD_F3_F0(a0)
-	fld f4,  TASK_THREAD_F4_F0(a0)
-	fld f5,  TASK_THREAD_F5_F0(a0)
-	fld f6,  TASK_THREAD_F6_F0(a0)
-	fld f7,  TASK_THREAD_F7_F0(a0)
-	fld f8,  TASK_THREAD_F8_F0(a0)
-	fld f9,  TASK_THREAD_F9_F0(a0)
-	fld f10, TASK_THREAD_F10_F0(a0)
-	fld f11, TASK_THREAD_F11_F0(a0)
-	fld f12, TASK_THREAD_F12_F0(a0)
-	fld f13, TASK_THREAD_F13_F0(a0)
-	fld f14, TASK_THREAD_F14_F0(a0)
-	fld f15, TASK_THREAD_F15_F0(a0)
-	fld f16, TASK_THREAD_F16_F0(a0)
-	fld f17, TASK_THREAD_F17_F0(a0)
-	fld f18, TASK_THREAD_F18_F0(a0)
-	fld f19, TASK_THREAD_F19_F0(a0)
-	fld f20, TASK_THREAD_F20_F0(a0)
-	fld f21, TASK_THREAD_F21_F0(a0)
-	fld f22, TASK_THREAD_F22_F0(a0)
-	fld f23, TASK_THREAD_F23_F0(a0)
-	fld f24, TASK_THREAD_F24_F0(a0)
-	fld f25, TASK_THREAD_F25_F0(a0)
-	fld f26, TASK_THREAD_F26_F0(a0)
-	fld f27, TASK_THREAD_F27_F0(a0)
-	fld f28, TASK_THREAD_F28_F0(a0)
-	fld f29, TASK_THREAD_F29_F0(a0)
-	fld f30, TASK_THREAD_F30_F0(a0)
-	fld f31, TASK_THREAD_F31_F0(a0)
-	fscsr t0
-	csrc sstatus, t1
-	ret
-ENDPROC(__fstate_restore)
-
-
 	.section ".rodata"
 	/* Exception vector table */
 ENTRY(excp_vect_table)
diff --git a/arch/riscv/kernel/fpu.S b/arch/riscv/kernel/fpu.S
new file mode 100644
index 000000000000..1defb0618aff
--- /dev/null
+++ b/arch/riscv/kernel/fpu.S
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/asm.h>
+#include <asm/csr.h>
+#include <asm/asm-offsets.h>
+
+ENTRY(__fstate_save)
+	li  a2,  TASK_THREAD_F0
+	add a0, a0, a2
+	li t1, SR_FS
+	csrs sstatus, t1
+	frcsr t0
+	fsd f0,  TASK_THREAD_F0_F0(a0)
+	fsd f1,  TASK_THREAD_F1_F0(a0)
+	fsd f2,  TASK_THREAD_F2_F0(a0)
+	fsd f3,  TASK_THREAD_F3_F0(a0)
+	fsd f4,  TASK_THREAD_F4_F0(a0)
+	fsd f5,  TASK_THREAD_F5_F0(a0)
+	fsd f6,  TASK_THREAD_F6_F0(a0)
+	fsd f7,  TASK_THREAD_F7_F0(a0)
+	fsd f8,  TASK_THREAD_F8_F0(a0)
+	fsd f9,  TASK_THREAD_F9_F0(a0)
+	fsd f10, TASK_THREAD_F10_F0(a0)
+	fsd f11, TASK_THREAD_F11_F0(a0)
+	fsd f12, TASK_THREAD_F12_F0(a0)
+	fsd f13, TASK_THREAD_F13_F0(a0)
+	fsd f14, TASK_THREAD_F14_F0(a0)
+	fsd f15, TASK_THREAD_F15_F0(a0)
+	fsd f16, TASK_THREAD_F16_F0(a0)
+	fsd f17, TASK_THREAD_F17_F0(a0)
+	fsd f18, TASK_THREAD_F18_F0(a0)
+	fsd f19, TASK_THREAD_F19_F0(a0)
+	fsd f20, TASK_THREAD_F20_F0(a0)
+	fsd f21, TASK_THREAD_F21_F0(a0)
+	fsd f22, TASK_THREAD_F22_F0(a0)
+	fsd f23, TASK_THREAD_F23_F0(a0)
+	fsd f24, TASK_THREAD_F24_F0(a0)
+	fsd f25, TASK_THREAD_F25_F0(a0)
+	fsd f26, TASK_THREAD_F26_F0(a0)
+	fsd f27, TASK_THREAD_F27_F0(a0)
+	fsd f28, TASK_THREAD_F28_F0(a0)
+	fsd f29, TASK_THREAD_F29_F0(a0)
+	fsd f30, TASK_THREAD_F30_F0(a0)
+	fsd f31, TASK_THREAD_F31_F0(a0)
+	sw t0, TASK_THREAD_FCSR_F0(a0)
+	csrc sstatus, t1
+	ret
+ENDPROC(__fstate_save)
+
+ENTRY(__fstate_restore)
+	li  a2,  TASK_THREAD_F0
+	add a0, a0, a2
+	li t1, SR_FS
+	lw t0, TASK_THREAD_FCSR_F0(a0)
+	csrs sstatus, t1
+	fld f0,  TASK_THREAD_F0_F0(a0)
+	fld f1,  TASK_THREAD_F1_F0(a0)
+	fld f2,  TASK_THREAD_F2_F0(a0)
+	fld f3,  TASK_THREAD_F3_F0(a0)
+	fld f4,  TASK_THREAD_F4_F0(a0)
+	fld f5,  TASK_THREAD_F5_F0(a0)
+	fld f6,  TASK_THREAD_F6_F0(a0)
+	fld f7,  TASK_THREAD_F7_F0(a0)
+	fld f8,  TASK_THREAD_F8_F0(a0)
+	fld f9,  TASK_THREAD_F9_F0(a0)
+	fld f10, TASK_THREAD_F10_F0(a0)
+	fld f11, TASK_THREAD_F11_F0(a0)
+	fld f12, TASK_THREAD_F12_F0(a0)
+	fld f13, TASK_THREAD_F13_F0(a0)
+	fld f14, TASK_THREAD_F14_F0(a0)
+	fld f15, TASK_THREAD_F15_F0(a0)
+	fld f16, TASK_THREAD_F16_F0(a0)
+	fld f17, TASK_THREAD_F17_F0(a0)
+	fld f18, TASK_THREAD_F18_F0(a0)
+	fld f19, TASK_THREAD_F19_F0(a0)
+	fld f20, TASK_THREAD_F20_F0(a0)
+	fld f21, TASK_THREAD_F21_F0(a0)
+	fld f22, TASK_THREAD_F22_F0(a0)
+	fld f23, TASK_THREAD_F23_F0(a0)
+	fld f24, TASK_THREAD_F24_F0(a0)
+	fld f25, TASK_THREAD_F25_F0(a0)
+	fld f26, TASK_THREAD_F26_F0(a0)
+	fld f27, TASK_THREAD_F27_F0(a0)
+	fld f28, TASK_THREAD_F28_F0(a0)
+	fld f29, TASK_THREAD_F29_F0(a0)
+	fld f30, TASK_THREAD_F30_F0(a0)
+	fld f31, TASK_THREAD_F31_F0(a0)
+	fscsr t0
+	csrc sstatus, t1
+	ret
+ENDPROC(__fstate_restore)
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index c4d2c63f9a29..711190d473d4 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -47,6 +47,8 @@ ENTRY(_start)
 	/* Save hart ID and DTB physical address */
 	mv s0, a0
 	mv s1, a1
+	la a2, boot_cpu_hartid
+	REG_S a0, (a2)
 
 	/* Initialize page tables and relocate to virtual addresses */
 	la sp, init_thread_union + THREAD_SIZE
@@ -55,7 +57,7 @@ ENTRY(_start)
 
 	/* Restore C environment */
 	la tp, init_task
-	sw s0, TASK_TI_CPU(tp)
+	sw zero, TASK_TI_CPU(tp)
 
 	la sp, init_thread_union
 	li a0, ASM_THREAD_SIZE
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 0cfac48a1272..48e6b7db83a1 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -8,6 +8,8 @@
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>
+#include <linux/seq_file.h>
+#include <asm/smp.h>
 
 /*
  * Possible interrupt causes:
@@ -24,12 +26,18 @@
  */
 #define INTERRUPT_CAUSE_FLAG	(1UL << (__riscv_xlen - 1))
 
-asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause)
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	show_ipi_stats(p, prec);
+	return 0;
+}
+
+asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
 
 	irq_enter();
-	switch (cause & ~INTERRUPT_CAUSE_FLAG) {
+	switch (regs->scause & ~INTERRUPT_CAUSE_FLAG) {
 	case INTERRUPT_CAUSE_TIMER:
 		riscv_timer_interrupt();
 		break;
diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
index 5721624886a1..8a5593ff9ff3 100644
--- a/arch/riscv/kernel/mcount.S
+++ b/arch/riscv/kernel/mcount.S
@@ -75,7 +75,6 @@ ENTRY(return_to_handler)
 	RESTORE_RET_ABI_STATE
 	jalr	a1
 ENDPROC(return_to_handler)
-EXPORT_SYMBOL(return_to_handler)
 #endif
 
 #ifndef CONFIG_DYNAMIC_FTRACE
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index d7c6ca7c95ae..bef19993ea92 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -76,7 +76,9 @@ void show_regs(struct pt_regs *regs)
 void start_thread(struct pt_regs *regs, unsigned long pc,
 	unsigned long sp)
 {
-	regs->sstatus = SR_SPIE /* User mode, irqs on */ | SR_FS_INITIAL;
+	regs->sstatus = SR_SPIE;
+	if (has_fpu)
+		regs->sstatus |= SR_FS_INITIAL;
 	regs->sepc = pc;
 	regs->sp = sp;
 	set_fs(USER_DS);
@@ -84,12 +86,14 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
 
 void flush_thread(void)
 {
+#ifdef CONFIG_FPU
 	/*
 	 * Reset FPU context
 	 *	frm: round to nearest, ties to even (IEEE default)
 	 *	fflags: accrued exceptions cleared
 	 */
 	memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
+#endif
 }
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
index 9f82a7e34c64..60f1e02eed36 100644
--- a/arch/riscv/kernel/ptrace.c
+++ b/arch/riscv/kernel/ptrace.c
@@ -28,6 +28,9 @@
 
 enum riscv_regset {
 	REGSET_X,
+#ifdef CONFIG_FPU
+	REGSET_F,
+#endif
 };
 
 static int riscv_gpr_get(struct task_struct *target,
@@ -54,6 +57,45 @@ static int riscv_gpr_set(struct task_struct *target,
 	return ret;
 }
 
+#ifdef CONFIG_FPU
+static int riscv_fpr_get(struct task_struct *target,
+			 const struct user_regset *regset,
+			 unsigned int pos, unsigned int count,
+			 void *kbuf, void __user *ubuf)
+{
+	int ret;
+	struct __riscv_d_ext_state *fstate = &target->thread.fstate;
+
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
+				  offsetof(struct __riscv_d_ext_state, fcsr));
+	if (!ret) {
+		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
+					  offsetof(struct __riscv_d_ext_state, fcsr) +
+					  sizeof(fstate->fcsr));
+	}
+
+	return ret;
+}
+
+static int riscv_fpr_set(struct task_struct *target,
+			 const struct user_regset *regset,
+			 unsigned int pos, unsigned int count,
+			 const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	struct __riscv_d_ext_state *fstate = &target->thread.fstate;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
+				 offsetof(struct __riscv_d_ext_state, fcsr));
+	if (!ret) {
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
+					 offsetof(struct __riscv_d_ext_state, fcsr) +
+					 sizeof(fstate->fcsr));
+	}
+
+	return ret;
+}
+#endif
 
 static const struct user_regset riscv_user_regset[] = {
 	[REGSET_X] = {
@@ -64,6 +106,16 @@ static const struct user_regset riscv_user_regset[] = {
 		.get = &riscv_gpr_get,
 		.set = &riscv_gpr_set,
 	},
+#ifdef CONFIG_FPU
+	[REGSET_F] = {
+		.core_note_type = NT_PRFPREG,
+		.n = ELF_NFPREG,
+		.size = sizeof(elf_fpreg_t),
+		.align = sizeof(elf_fpreg_t),
+		.get = &riscv_fpr_get,
+		.set = &riscv_fpr_set,
+	},
+#endif
 };
 
 static const struct user_regset_view riscv_user_native_view = {
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index db20dc630e7e..2c290e6aaa6e 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -81,19 +81,22 @@ EXPORT_SYMBOL(empty_zero_page);
 
 /* The lucky hart to first increment this variable will boot the other cores */
 atomic_t hart_lottery;
+unsigned long boot_cpu_hartid;
+
+unsigned long __cpuid_to_hartid_map[NR_CPUS] = {
+	[0 ... NR_CPUS-1] = INVALID_HARTID
+};
+
+void __init smp_setup_processor_id(void)
+{
+	cpuid_to_hartid_map(0) = boot_cpu_hartid;
+}
 
 #ifdef CONFIG_BLK_DEV_INITRD
 static void __init setup_initrd(void)
 {
-	extern char __initramfs_start[];
-	extern unsigned long __initramfs_size;
 	unsigned long size;
 
-	if (__initramfs_size > 0) {
-		initrd_start = (unsigned long)(&__initramfs_start);
-		initrd_end = initrd_start + __initramfs_size;
-	}
-
 	if (initrd_start >= initrd_end) {
 		printk(KERN_INFO "initrd not found or empty");
 		goto disable;
@@ -193,7 +196,7 @@ static void __init setup_bootmem(void)
 	BUG_ON(mem_size == 0);
 
 	set_max_mapnr(PFN_DOWN(mem_size));
-	max_low_pfn = pfn_base + PFN_DOWN(mem_size);
+	max_low_pfn = memblock_end_of_DRAM();
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	setup_initrd();
@@ -234,7 +237,10 @@ void __init setup_arch(char **cmdline_p)
 	setup_bootmem();
 	paging_init();
 	unflatten_device_tree();
+
+#ifdef CONFIG_SWIOTLB
 	swiotlb_init(1);
+#endif
 
 #ifdef CONFIG_SMP
 	setup_smp();
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 718d0c984ef0..f9b5e7e352ef 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -37,45 +37,69 @@ struct rt_sigframe {
 	struct ucontext uc;
 };
 
-static long restore_d_state(struct pt_regs *regs,
-	struct __riscv_d_ext_state __user *state)
+#ifdef CONFIG_FPU
+static long restore_fp_state(struct pt_regs *regs,
+			     union __riscv_fp_state *sc_fpregs)
 {
 	long err;
+	struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
+	size_t i;
+
 	err = __copy_from_user(&current->thread.fstate, state, sizeof(*state));
-	if (likely(!err))
-		fstate_restore(current, regs);
+	if (unlikely(err))
+		return err;
+
+	fstate_restore(current, regs);
+
+	/* We support no other extension state at this time. */
+	for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
+		u32 value;
+
+		err = __get_user(value, &sc_fpregs->q.reserved[i]);
+		if (unlikely(err))
+			break;
+		if (value != 0)
+			return -EINVAL;
+	}
+
 	return err;
 }
 
-static long save_d_state(struct pt_regs *regs,
-	struct __riscv_d_ext_state __user *state)
+static long save_fp_state(struct pt_regs *regs,
+			  union __riscv_fp_state *sc_fpregs)
 {
+	long err;
+	struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
+	size_t i;
+
 	fstate_save(current, regs);
-	return __copy_to_user(state, &current->thread.fstate, sizeof(*state));
+	err = __copy_to_user(state, &current->thread.fstate, sizeof(*state));
+	if (unlikely(err))
+		return err;
+
+	/* We support no other extension state at this time. */
+	for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
+		err = __put_user(0, &sc_fpregs->q.reserved[i]);
+		if (unlikely(err))
+			break;
+	}
+
+	return err;
 }
+#else
+#define save_fp_state(task, regs) (0)
+#define restore_fp_state(task, regs) (0)
+#endif
 
 static long restore_sigcontext(struct pt_regs *regs,
 	struct sigcontext __user *sc)
 {
 	long err;
-	size_t i;
 	/* sc_regs is structured the same as the start of pt_regs */
 	err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs));
-	if (unlikely(err))
-		return err;
 	/* Restore the floating-point state. */
-	err = restore_d_state(regs, &sc->sc_fpregs.d);
-	if (unlikely(err))
-		return err;
-	/* We support no other extension state at this time. */
-	for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) {
-		u32 value;
-		err = __get_user(value, &sc->sc_fpregs.q.reserved[i]);
-		if (unlikely(err))
-			break;
-		if (value != 0)
-			return -EINVAL;
-	}
+	if (has_fpu)
+		err |= restore_fp_state(regs, &sc->sc_fpregs);
 	return err;
 }
 
@@ -124,14 +148,11 @@ static long setup_sigcontext(struct rt_sigframe __user *frame,
 {
 	struct sigcontext __user *sc = &frame->uc.uc_mcontext;
 	long err;
-	size_t i;
 	/* sc_regs is structured the same as the start of pt_regs */
 	err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs));
 	/* Save the floating-point state. */
-	err |= save_d_state(regs, &sc->sc_fpregs.d);
-	/* We support no other extension state at this time. */
-	for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++)
-		err |= __put_user(0, &sc->sc_fpregs.q.reserved[i]);
+	if (has_fpu)
+		err |= save_fp_state(regs, &sc->sc_fpregs);
 	return err;
 }
 
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 906fe21ea21b..57b1383e5ef7 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -22,23 +22,44 @@
 #include <linux/interrupt.h>
 #include <linux/smp.h>
 #include <linux/sched.h>
+#include <linux/seq_file.h>
 
 #include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
 
-/* A collection of single bit ipi messages.  */
-static struct {
-	unsigned long bits ____cacheline_aligned;
-} ipi_data[NR_CPUS] __cacheline_aligned;
-
 enum ipi_message_type {
 	IPI_RESCHEDULE,
 	IPI_CALL_FUNC,
 	IPI_MAX
 };
 
+/* A collection of single bit ipi messages.  */
+static struct {
+	unsigned long stats[IPI_MAX] ____cacheline_aligned;
+	unsigned long bits ____cacheline_aligned;
+} ipi_data[NR_CPUS] __cacheline_aligned;
+
+int riscv_hartid_to_cpuid(int hartid)
+{
+	int i = -1;
+
+	for (i = 0; i < NR_CPUS; i++)
+		if (cpuid_to_hartid_map(i) == hartid)
+			return i;
 
+	pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
+	BUG();
+	return i;
+}
+
+void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)
+{
+	int cpu;
+
+	for_each_cpu(cpu, in)
+		cpumask_set_cpu(cpuid_to_hartid_map(cpu), out);
+}
 /* Unsupported */
 int setup_profiling_timer(unsigned int multiplier)
 {
@@ -48,6 +69,7 @@ int setup_profiling_timer(unsigned int multiplier)
 void riscv_software_interrupt(void)
 {
 	unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
+	unsigned long *stats = ipi_data[smp_processor_id()].stats;
 
 	/* Clear pending IPI */
 	csr_clear(sip, SIE_SSIE);
@@ -62,11 +84,15 @@ void riscv_software_interrupt(void)
 		if (ops == 0)
 			return;
 
-		if (ops & (1 << IPI_RESCHEDULE))
+		if (ops & (1 << IPI_RESCHEDULE)) {
+			stats[IPI_RESCHEDULE]++;
 			scheduler_ipi();
+		}
 
-		if (ops & (1 << IPI_CALL_FUNC))
+		if (ops & (1 << IPI_CALL_FUNC)) {
+			stats[IPI_CALL_FUNC]++;
 			generic_smp_call_function_interrupt();
+		}
 
 		BUG_ON((ops >> IPI_MAX) != 0);
 
@@ -78,14 +104,36 @@ void riscv_software_interrupt(void)
 static void
 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
 {
-	int i;
+	int cpuid, hartid;
+	struct cpumask hartid_mask;
 
+	cpumask_clear(&hartid_mask);
 	mb();
-	for_each_cpu(i, to_whom)
-		set_bit(operation, &ipi_data[i].bits);
-
+	for_each_cpu(cpuid, to_whom) {
+		set_bit(operation, &ipi_data[cpuid].bits);
+		hartid = cpuid_to_hartid_map(cpuid);
+		cpumask_set_cpu(hartid, &hartid_mask);
+	}
 	mb();
-	sbi_send_ipi(cpumask_bits(to_whom));
+	sbi_send_ipi(cpumask_bits(&hartid_mask));
+}
+
+static const char * const ipi_names[] = {
+	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
+	[IPI_CALL_FUNC]		= "Function call interrupts",
+};
+
+void show_ipi_stats(struct seq_file *p, int prec)
+{
+	unsigned int cpu, i;
+
+	for (i = 0; i < IPI_MAX; i++) {
+		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
+			   prec >= 4 ? " " : "");
+		for_each_online_cpu(cpu)
+			seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]);
+		seq_printf(p, " %s\n", ipi_names[i]);
+	}
 }
 
 void arch_send_call_function_ipi_mask(struct cpumask *mask)
@@ -127,7 +175,7 @@ void smp_send_reschedule(int cpu)
 void flush_icache_mm(struct mm_struct *mm, bool local)
 {
 	unsigned int cpu;
-	cpumask_t others, *mask;
+	cpumask_t others, hmask, *mask;
 
 	preempt_disable();
 
@@ -145,9 +193,11 @@ void flush_icache_mm(struct mm_struct *mm, bool local)
 	 */
 	cpumask_andnot(&others, mm_cpumask(mm), cpumask_of(cpu));
 	local |= cpumask_empty(&others);
-	if (mm != current->active_mm || !local)
-		sbi_remote_fence_i(others.bits);
-	else {
+	if (mm != current->active_mm || !local) {
+		cpumask_clear(&hmask);
+		riscv_cpuid_to_hartid_mask(&others, &hmask);
+		sbi_remote_fence_i(hmask.bits);
+	} else {
 		/*
 		 * It's assumed that at least one strongly ordered operation is
 		 * performed on this hart between setting a hart's cpumask bit
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 56abab6a9812..18cda0e8cf94 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -30,6 +30,7 @@
 #include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/sched/task_stack.h>
+#include <linux/sched/mm.h>
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
@@ -50,25 +51,33 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 void __init setup_smp(void)
 {
 	struct device_node *dn = NULL;
-	int hart, im_okay_therefore_i_am = 0;
+	int hart;
+	bool found_boot_cpu = false;
+	int cpuid = 1;
 
 	while ((dn = of_find_node_by_type(dn, "cpu"))) {
-		hart = riscv_of_processor_hart(dn);
-		if (hart >= 0) {
-			set_cpu_possible(hart, true);
-			set_cpu_present(hart, true);
-			if (hart == smp_processor_id()) {
-				BUG_ON(im_okay_therefore_i_am);
-				im_okay_therefore_i_am = 1;
-			}
+		hart = riscv_of_processor_hartid(dn);
+		if (hart < 0)
+			continue;
+
+		if (hart == cpuid_to_hartid_map(0)) {
+			BUG_ON(found_boot_cpu);
+			found_boot_cpu = 1;
+			continue;
 		}
+
+		cpuid_to_hartid_map(cpuid) = hart;
+		set_cpu_possible(cpuid, true);
+		set_cpu_present(cpuid, true);
+		cpuid++;
 	}
 
-	BUG_ON(!im_okay_therefore_i_am);
+	BUG_ON(!found_boot_cpu);
 }
 
 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
+	int hartid = cpuid_to_hartid_map(cpu);
 	tidle->thread_info.cpu = cpu;
 
 	/*
@@ -79,8 +88,9 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 	 * the spinning harts that they can continue the boot process.
 	 */
 	smp_mb();
-	__cpu_up_stack_pointer[cpu] = task_stack_page(tidle) + THREAD_SIZE;
-	__cpu_up_task_pointer[cpu] = tidle;
+	WRITE_ONCE(__cpu_up_stack_pointer[hartid],
+		  task_stack_page(tidle) + THREAD_SIZE);
+	WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle);
 
 	while (!cpu_online(cpu))
 		cpu_relax();
@@ -100,14 +110,22 @@ asmlinkage void __init smp_callin(void)
 	struct mm_struct *mm = &init_mm;
 
 	/* All kernel threads share the same mm context.  */
-	atomic_inc(&mm->mm_count);
+	mmgrab(mm);
 	current->active_mm = mm;
 
 	trap_init();
 	notify_cpu_starting(smp_processor_id());
 	set_cpu_online(smp_processor_id(), 1);
+	/*
+	 * Remote TLB flushes are ignored while the CPU is offline, so emit
+	 * a local TLB flush right now just in case.
+	 */
 	local_flush_tlb_all();
-	local_irq_enable();
+	/*
+	 * Disable preemption before enabling interrupts, so we don't try to
+	 * schedule a CPU that hasn't actually started yet.
+	 */
 	preempt_disable();
+	local_irq_enable();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 568026ccf6e8..fb03a4482ad6 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -65,24 +65,11 @@ SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
 	uintptr_t, flags)
 {
-#ifdef CONFIG_SMP
-	struct mm_struct *mm = current->mm;
-	bool local = (flags & SYS_RISCV_FLUSH_ICACHE_LOCAL) != 0;
-#endif
-
 	/* Check the reserved flags. */
 	if (unlikely(flags & ~SYS_RISCV_FLUSH_ICACHE_ALL))
 		return -EINVAL;
 
-	/*
-	 * Without CONFIG_SMP flush_icache_mm is a just a flush_icache_all(),
-	 * which generates unused variable warnings all over this function.
-	 */
-#ifdef CONFIG_SMP
-	flush_icache_mm(mm, local);
-#else
-	flush_icache_all();
-#endif
+	flush_icache_mm(current->mm, flags & SYS_RISCV_FLUSH_ICACHE_LOCAL);
 
 	return 0;
 }