3 files changed, 17 insertions, 4 deletions

diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 3a5a2ee31547..b4a7d4427fbb 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -64,7 +64,7 @@ int riscv_of_processor_hartid(struct device_node *node)
 
 static void print_isa(struct seq_file *f, const char *orig_isa)
 {
-        static const char *ext = "mafdc";
+        static const char *ext = "mafdcsu";
         const char *isa = orig_isa;
         const char *e;
 
@@ -88,11 +88,14 @@ static void print_isa(struct seq_file *f, const char *orig_isa)
         /*
          * 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.
+         * extension bits when they're in order. Hide the supervisor (S)
+         * extension from userspace as it's not accessible from there.
          */
         for (e = ext; *e != '\0'; ++e) {
                 if (isa[0] == e[0]) {
-                        seq_write(f, isa, 1);
+                        if (isa[0] != 's')
+                                seq_write(f, isa, 1);
+
                         isa++;
                 }
         }
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 711190d473d4..fe884cd69abd 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -44,6 +44,16 @@ ENTRY(_start)
         amoadd.w a3, a2, (a3)
         bnez a3, .Lsecondary_start
 
+        /* Clear BSS for flat non-ELF images */
+        la a3, __bss_start
+        la a4, __bss_stop
+        ble a4, a3, clear_bss_done
+clear_bss:
+        REG_S zero, (a3)
+        add a3, a3, RISCV_SZPTR
+        blt a3, a4, clear_bss
+clear_bss_done:
+
         /* Save hart ID and DTB physical address */
         mv s0, a0
         mv s1, a1
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index ece84991609c..65df1dfdc303 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -74,7 +74,7 @@ SECTIONS
                 *(.sbss*)
         }
 
-        BSS_SECTION(0, 0, 0)
+        BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0)
 
         EXCEPTION_TABLE(0x10)
         NOTES