summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-02 10:13:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-02 10:13:05 -0700
commitdb23baa28eb1f93df1fc175a419e7ffe5b6f1582 (patch)
tree05d5cbe5bd88d80322c7358344024fefabd6a4a3 /arch
parent4e3b9ce271b4b54d2293a3916d22e4ddc0c89aab (diff)
parentaa9887608e77b835d51f05a54940380391cd4e21 (diff)
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
Diffstat (limited to 'arch')
-rw-r--r--arch/riscv/include/asm/stackprotector.h4
-rw-r--r--arch/riscv/include/asm/timex.h13
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)