From 10243401059287868a5651f869a2494368872add Mon Sep 17 00:00:00 2001 From: Samuel Ortiz Date: Thu, 30 Nov 2023 12:17:02 +0100 Subject: RISC-V: Implement archrandom when Zkr is available MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The Zkr extension is ratified and provides 16 bits of entropy seed when reading the SEED CSR. We can implement arch_get_random_seed_longs() by doing multiple csrrw to that CSR and filling an unsigned long with valid entropy bits. Acked-by: Conor Dooley Signed-off-by: Samuel Ortiz Signed-off-by: Clément Léger Link: https://lore.kernel.org/r/20231130111704.1319081-1-cleger@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/csr.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/riscv/include/asm/csr.h') diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h index 306a19a5509c..510014051f5d 100644 --- a/arch/riscv/include/asm/csr.h +++ b/arch/riscv/include/asm/csr.h @@ -411,6 +411,15 @@ #define CSR_VTYPE 0xc21 #define CSR_VLENB 0xc22 +/* Scalar Crypto Extension - Entropy */ +#define CSR_SEED 0x015 +#define SEED_OPST_MASK _AC(0xC0000000, UL) +#define SEED_OPST_BIST _AC(0x00000000, UL) +#define SEED_OPST_WAIT _AC(0x40000000, UL) +#define SEED_OPST_ES16 _AC(0x80000000, UL) +#define SEED_OPST_DEAD _AC(0xC0000000, UL) +#define SEED_ENTROPY_MASK _AC(0xFFFF, UL) + #ifdef CONFIG_RISCV_M_MODE # define CSR_STATUS CSR_MSTATUS # define CSR_IE CSR_MIE -- cgit v1.2.3-59-g8ed1b