diff options
| -rw-r--r-- | arch/sh/Kconfig | 10 | ||||
| -rw-r--r-- | arch/sh/kernel/cpu/init.c | 19 |
2 files changed, 29 insertions, 0 deletions
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 4d16d891707..2715834f72b 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -366,6 +366,16 @@ config SH_STORE_QUEUES Selecting this option will enable an in-kernel API for manipulating the store queues integrated in the SH-4 processors. +config SPECULATIVE_EXECUTION + bool "Speculative subroutine return" + depends on CPU_SUBTYPE_SH7780 && EXPERIMENTAL + help + This enables support for a speculative instruction fetch for + subroutine return. There are various pitfalls associated with + this, as outlined in the SH7780 hardware manual. + + If unsure, say N. + config CPU_HAS_INTEVT bool diff --git a/arch/sh/kernel/cpu/init.c b/arch/sh/kernel/cpu/init.c index 726acfcb9b7..6451ad63017 100644 --- a/arch/sh/kernel/cpu/init.c +++ b/arch/sh/kernel/cpu/init.c @@ -41,6 +41,23 @@ __setup("no" __stringify(x), x##_setup); onchip_setup(fpu); onchip_setup(dsp); +#ifdef CONFIG_SPECULATIVE_EXECUTION +#define CPUOPM 0xff2f0000 +#define CPUOPM_RABD (1 << 5) + +static void __init speculative_execution_init(void) +{ + /* Clear RABD */ + ctrl_outl(ctrl_inl(CPUOPM) & ~CPUOPM_RABD, CPUOPM); + + /* Flush the update */ + (void)ctrl_inl(CPUOPM); + ctrl_barrier(); +} +#else +#define speculative_execution_init() do { } while (0) +#endif + /* * Generic first-level cache init */ @@ -261,4 +278,6 @@ asmlinkage void __init sh_cpu_init(void) */ ubc_wakeup(); #endif + + speculative_execution_init(); } |