1 files changed, 48 insertions, 6 deletions

diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 03ac3aa611f5..8955f2432c2d 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -23,6 +23,7 @@
 #include <asm/string.h>
 #include <asm/switch_to.h>
 #include <asm/thread_info.h>
+#include <asm/cpuidle.h>
 
 register unsigned long gp_in_global __asm__("gp");
 
@@ -37,7 +38,7 @@ extern asmlinkage void ret_from_kernel_thread(void);
 
 void arch_cpu_idle(void)
 {
-	wait_for_interrupt();
+	cpu_do_idle();
 	raw_local_irq_enable();
 }
 
@@ -83,6 +84,34 @@ void show_regs(struct pt_regs *regs)
 		dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
+#ifdef CONFIG_COMPAT
+static bool compat_mode_supported __read_mostly;
+
+bool compat_elf_check_arch(Elf32_Ehdr *hdr)
+{
+	return compat_mode_supported &&
+	       hdr->e_machine == EM_RISCV &&
+	       hdr->e_ident[EI_CLASS] == ELFCLASS32;
+}
+
+static int __init compat_mode_detect(void)
+{
+	unsigned long tmp = csr_read(CSR_STATUS);
+
+	csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32);
+	compat_mode_supported =
+			(csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32;
+
+	csr_write(CSR_STATUS, tmp);
+
+	pr_info("riscv: ELF compat mode %s",
+			compat_mode_supported ? "supported" : "unsupported");
+
+	return 0;
+}
+early_initcall(compat_mode_detect);
+#endif
+
 void start_thread(struct pt_regs *regs, unsigned long pc,
 	unsigned long sp)
 {
@@ -97,6 +126,15 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
 	}
 	regs->epc = pc;
 	regs->sp = sp;
+
+#ifdef CONFIG_64BIT
+	regs->status &= ~SR_UXL;
+
+	if (is_compat_task())
+		regs->status |= SR_UXL_32;
+	else
+		regs->status |= SR_UXL_64;
+#endif
 }
 
 void flush_thread(void)
@@ -119,13 +157,17 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 	return 0;
 }
 
-int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
-		struct task_struct *p, unsigned long tls)
+int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
+	unsigned long clone_flags = args->flags;
+	unsigned long usp = args->stack;
+	unsigned long tls = args->tls;
 	struct pt_regs *childregs = task_pt_regs(p);
 
+	memset(&p->thread.s, 0, sizeof(p->thread.s));
+
 	/* p->thread holds context to be restored by __switch_to() */
-	if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
+	if (unlikely(args->fn)) {
 		/* Kernel thread */
 		memset(childregs, 0, sizeof(struct pt_regs));
 		childregs->gp = gp_in_global;
@@ -133,8 +175,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
 		childregs->status = SR_PP | SR_PIE;
 
 		p->thread.ra = (unsigned long)ret_from_kernel_thread;
-		p->thread.s[0] = usp; /* fn */
-		p->thread.s[1] = arg;
+		p->thread.s[0] = (unsigned long)args->fn;
+		p->thread.s[1] = (unsigned long)args->fn_arg;
 	} else {
 		*childregs = *(current_pt_regs());
 		if (usp) /* User fork */