7 files changed, 24 insertions, 14 deletions

diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index 6a92a2fe198e..dac98348c6a3 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -39,6 +39,7 @@ void asm_offsets(void)
 	OFFSET(TASK_STACK, task_struct, stack);
 	OFFSET(TASK_TI, task_struct, thread_info);
 	OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags);
+	OFFSET(TASK_TI_PREEMPT_COUNT, task_struct, thread_info.preempt_count);
 	OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp);
 	OFFSET(TASK_TI_USER_SP, task_struct, thread_info.user_sp);
 	OFFSET(TASK_TI_CPU, task_struct, thread_info.cpu);
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 355166f57205..fd9b57c8b4ce 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -144,6 +144,10 @@ _save_context:
 	REG_L x2,  PT_SP(sp)
 	.endm
 
+#if !IS_ENABLED(CONFIG_PREEMPT)
+.set resume_kernel, restore_all
+#endif
+
 ENTRY(handle_exception)
 	SAVE_ALL
 
@@ -228,7 +232,7 @@ ret_from_exception:
 	REG_L s0, PT_SSTATUS(sp)
 	csrc sstatus, SR_SIE
 	andi s0, s0, SR_SPP
-	bnez s0, restore_all
+	bnez s0, resume_kernel
 
 resume_userspace:
 	/* Interrupts must be disabled here so flags are checked atomically */
@@ -250,6 +254,18 @@ restore_all:
 	RESTORE_ALL
 	sret
 
+#if IS_ENABLED(CONFIG_PREEMPT)
+resume_kernel:
+	REG_L s0, TASK_TI_PREEMPT_COUNT(tp)
+	bnez s0, restore_all
+need_resched:
+	REG_L s0, TASK_TI_FLAGS(tp)
+	andi s0, s0, _TIF_NEED_RESCHED
+	beqz s0, restore_all
+	call preempt_schedule_irq
+	j need_resched
+#endif
+
 work_pending:
 	/* Enter slow path for supplementary processing */
 	la ra, ret_from_exception
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 6e079e94b638..77564310235f 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -181,7 +181,7 @@ static void __init setup_bootmem(void)
 	BUG_ON(mem_size == 0);
 
 	set_max_mapnr(PFN_DOWN(mem_size));
-	max_low_pfn = memblock_end_of_DRAM();
+	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	setup_initrd();
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index fc185ecabb0a..18cda0e8cf94 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -57,15 +57,12 @@ void __init setup_smp(void)
 
 	while ((dn = of_find_node_by_type(dn, "cpu"))) {
 		hart = riscv_of_processor_hartid(dn);
-		if (hart < 0) {
-			of_node_put(dn);
+		if (hart < 0)
 			continue;
-		}
 
 		if (hart == cpuid_to_hartid_map(0)) {
 			BUG_ON(found_boot_cpu);
 			found_boot_cpu = 1;
-			of_node_put(dn);
 			continue;
 		}
 
@@ -73,7 +70,6 @@ void __init setup_smp(void)
 		set_cpu_possible(cpuid, true);
 		set_cpu_present(cpuid, true);
 		cpuid++;
-		of_node_put(dn);
 	}
 
 	BUG_ON(!found_boot_cpu);
diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index 582cb153eb24..0cd044122234 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -54,7 +54,6 @@ static int __init vdso_init(void)
 		struct page *pg;
 
 		pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
-		ClearPageReserved(pg);
 		vdso_pagelist[i] = pg;
 	}
 	vdso_pagelist[i] = virt_to_page(vdso_data);
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index eed1c137f618..fec62b24df89 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -2,9 +2,11 @@
 
 # Symbols present in the vdso
 vdso-syms  = rt_sigreturn
+ifdef CONFIG_64BIT
 vdso-syms += gettimeofday
 vdso-syms += clock_gettime
 vdso-syms += clock_getres
+endif
 vdso-syms += getcpu
 vdso-syms += flush_icache
 
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index 1e1395d63dab..65df1dfdc303 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -18,8 +18,6 @@
 #include <asm/cache.h>
 #include <asm/thread_info.h>
 
-#define MAX_BYTES_PER_LONG	0x10
-
 OUTPUT_ARCH(riscv)
 ENTRY(_start)
 
@@ -76,6 +74,8 @@ SECTIONS
 		*(.sbss*)
 	}
 
+	BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0)
+
 	EXCEPTION_TABLE(0x10)
 	NOTES
 
@@ -83,10 +83,6 @@ SECTIONS
 		*(.rel.dyn*)
 	}
 
-	BSS_SECTION(MAX_BYTES_PER_LONG,
-		    MAX_BYTES_PER_LONG,
-		    MAX_BYTES_PER_LONG)
-
 	_end = .;
 
 	STABS_DEBUG