On Fri, May 23, 2025 at 12:19:27PM +0200, Clément Léger wrote:
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
Reviewed-by: Charlie Jenkins charlie@rivosinc.com Tested-by: Charlie Jenkins charlie@rivosinc.com
arch/riscv/include/asm/cpufeature.h | 6 ++++++ arch/riscv/kernel/traps_misaligned.c | 17 +++++++++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h index 2bfa4ef383ed..fbd0e4306c93 100644 --- a/arch/riscv/include/asm/cpufeature.h +++ b/arch/riscv/include/asm/cpufeature.h @@ -81,6 +81,12 @@ static inline bool unaligned_ctl_available(void) #if defined(CONFIG_RISCV_MISALIGNED) DECLARE_PER_CPU(long, misaligned_access_speed); +bool misaligned_traps_can_delegate(void); +#else +static inline bool misaligned_traps_can_delegate(void) +{
- return false;
+} #endif bool __init 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 7ecaa8103fe7..93043924fe6c 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -724,10 +724,10 @@ 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) && @@ -763,6 +763,7 @@ static int cpu_online_sbi_unaligned_setup(unsigned int cpu __always_unused) { return 0; }
#endif int cpu_online_unaligned_access_init(unsigned int cpu) @@ -775,3 +776,15 @@ 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 implement the 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);
2.49.0