From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> This needs to add Sv32 mode in the SATP CSR of RV64 ISA, a novel extension of 64-bit processors' MMU. It could save a bit of page table footprint and improve the page table walk performance: s64ilp32 with Sv39: PageTables: 136 kB s64ilp32 with Sv32: PageTables: 60 kB Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> --- arch/riscv/Kconfig | 11 ++++++++++- arch/riscv/Kconfig.errata | 2 +- arch/riscv/include/asm/csr.h | 1 + 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 5a3eb5e7d67a..1d3a236d2c45 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -481,7 +481,7 @@ config RISCV_ISA_SVNAPOT config RISCV_ISA_SVPBMT bool "Svpbmt extension support for supervisor mode page-based memory types" - depends on 64BIT && MMU + depends on !MMU_SV32 && MMU depends on RISCV_ALTERNATIVE default y help @@ -638,6 +638,15 @@ config THREAD_SIZE_ORDER Specify the Pages of thread stack size (from 4KB to 64KB), which also affects irq stack size, which is equal to thread stack size. +config MMU_SV32 + bool "MMU Sv32" + depends on 32BIT && MMU + help + ARCH_RV32I only supports MMU Sv32 mode, but ARCH_RV64ILP32 supports + MMU Sv39 & Sv32 (MMU Sv32 is optional for RV64 hardware). + + If unsure, say N. + endmenu # "Platform type" menu "Kernel features" diff --git a/arch/riscv/Kconfig.errata b/arch/riscv/Kconfig.errata index 0c8f4652cd82..1aa85a427ff3 100644 --- a/arch/riscv/Kconfig.errata +++ b/arch/riscv/Kconfig.errata @@ -44,7 +44,7 @@ config ERRATA_THEAD config ERRATA_THEAD_PBMT bool "Apply T-Head memory type errata" - depends on ERRATA_THEAD && 64BIT && MMU + depends on ERRATA_THEAD && !MMU_SV32 && MMU select RISCV_ALTERNATIVE_EARLY default y help diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h index 03acdedc100d..aa78c5f20d75 100644 --- a/arch/riscv/include/asm/csr.h +++ b/arch/riscv/include/asm/csr.h @@ -65,6 +65,7 @@ #define SATP_ASID_MASK _AC(0x1FF, UXL) #else #define SATP_PPN _AC(0x00000FFFFFFFFFFF, UXL) +#define SATP_MODE_32 _AC(0x1000000000000000, UXL) #define SATP_MODE_39 _AC(0x8000000000000000, UXL) #define SATP_MODE_48 _AC(0x9000000000000000, UXL) #define SATP_MODE_57 _AC(0xa000000000000000, UXL) -- 2.36.1
