RISC-V Fixes for 5.9

I have 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.
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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
This commit is contained in:
Linus Torvalds 2020-10-02 10:13:05 -07:00
commit db23baa28e
3 changed files with 14 additions and 4 deletions

View File

@ -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;

View File

@ -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)

View File

@ -38,6 +38,7 @@ static unsigned int clint_timer_irq;
#ifdef CONFIG_RISCV_M_MODE
u64 __iomem *clint_time_val;
EXPORT_SYMBOL(clint_time_val);
#endif
static void clint_send_ipi(const struct cpumask *target)