Merge tag 'riscv-for-linus-5.9-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:
 "Two fixes for this week:

   - The addition of a symbol export for clint_time_val, which has been
     inlined into some timex functions and can be used by drivers.

   - A fix to avoid calling get_cycles() before the timers have been
     probed.

  These both only effect !MMU systems"

* tag 'riscv-for-linus-5.9-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Check clint_time_val before use
  clocksource: clint: Export clint_time_val for modules

2 files changed, 13 insertions, 4 deletions

diff --git a/arch/riscv/include/asm/stackprotector.h b/arch/riscv/include/asm/stackprotector.h
index d95f7b2a7f37..5962f8891f06 100644
--- a/arch/riscv/include/asm/stackprotector.h
+++ b/arch/riscv/include/asm/stackprotector.h
@@ -5,7 +5,6 @@
 
 #include <linux/random.h>
 #include <linux/version.h>
-#include <asm/timex.h>
 
 extern unsigned long __stack_chk_guard;
 
@@ -18,12 +17,9 @@ extern unsigned long __stack_chk_guard;
 static __always_inline void boot_init_stack_canary(void)
 {
 	unsigned long canary;
-	unsigned long tsc;
 
 	/* Try to get a semi random initial value. */
 	get_random_bytes(&canary, sizeof(canary));
-	tsc = get_cycles();
-	canary += tsc + (tsc << BITS_PER_LONG/2);
 	canary ^= LINUX_VERSION_CODE;
 	canary &= CANARY_MASK;
 
diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h
index 7f659dda0032..ab104905d4db 100644
--- a/arch/riscv/include/asm/timex.h
+++ b/arch/riscv/include/asm/timex.h
@@ -33,6 +33,19 @@ static inline u32 get_cycles_hi(void)
 #define get_cycles_hi get_cycles_hi
 #endif /* CONFIG_64BIT */
 
+/*
+ * Much like MIPS, we may not have a viable counter to use at an early point
+ * in the boot process. Unfortunately we don't have a fallback, so instead
+ * we just return 0.
+ */
+static inline unsigned long random_get_entropy(void)
+{
+	if (unlikely(clint_time_val == NULL))
+		return 0;
+	return get_cycles();
+}
+#define random_get_entropy()	random_get_entropy()
+
 #else /* CONFIG_RISCV_M_MODE */
 
 static inline cycles_t get_cycles(void)