Checking for the delegability of the misaligned access trap is needed for the KVM FWFT extension implementation. Add a function to get the delegability of the misaligned trap exception.
Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com --- arch/riscv/include/asm/cpufeature.h | 5 +++++ arch/riscv/kernel/traps_misaligned.c | 17 +++++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h index ad7d26788e6a..8b97cba99fc3 100644 --- a/arch/riscv/include/asm/cpufeature.h +++ b/arch/riscv/include/asm/cpufeature.h @@ -69,12 +69,17 @@ int cpu_online_unaligned_access_init(unsigned int cpu); #if defined(CONFIG_RISCV_SCALAR_MISALIGNED) void unaligned_emulation_finish(void); bool unaligned_ctl_available(void); +bool misaligned_traps_can_delegate(void); DECLARE_PER_CPU(long, misaligned_access_speed); #else static inline bool unaligned_ctl_available(void) { return false; } +static inline bool misaligned_traps_can_delegate(void) +{ + return false; +} #endif
bool check_vector_unaligned_access_emulated_all_cpus(void); diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index 3c77fc78fe4f..0fb663ac200f 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -715,10 +715,10 @@ static int cpu_online_check_unaligned_access_emulated(unsigned int cpu) } #endif
-#ifdef CONFIG_RISCV_SBI - static bool misaligned_traps_delegated;
+#ifdef CONFIG_RISCV_SBI + static int cpu_online_sbi_unaligned_setup(unsigned int cpu) { if (sbi_fwft_set(SBI_FWFT_MISALIGNED_EXC_DELEG, 1, 0) && @@ -760,6 +760,7 @@ static int cpu_online_sbi_unaligned_setup(unsigned int cpu __always_unused) { return 0; } + #endif
int cpu_online_unaligned_access_init(unsigned int cpu) @@ -772,3 +773,15 @@ int cpu_online_unaligned_access_init(unsigned int cpu)
return cpu_online_check_unaligned_access_emulated(cpu); } + +bool misaligned_traps_can_delegate(void) +{ + /* + * Either we successfully requested misaligned traps delegation for all + * CPUS or the SBI does not implemented FWFT extension but delegated the + * exception by default. + */ + return misaligned_traps_delegated || + all_cpus_unaligned_scalar_access_emulated(); +} +EXPORT_SYMBOL_GPL(misaligned_traps_can_delegate);