The Linux kernel parses the ISA extensions from "riscv,isa" DT property. It used to parse only the single letter base extensions until now. A generic ISA extension parsing framework was proposed[1] recently that can parse multi-letter ISA extensions as well.
Generate the extended ISA string by appending the available ISA extensions to the "riscv,isa" string if it is enabled so that kernel can process it. [1] https://lkml.org/lkml/2022/2/15/263 Suggested-by: Heiko Stubner <he...@sntech.de> Signed-off-by: Atish Patra <ati...@rivosinc.com> --- Changes from v2->v3: 1. Used g_strconcat to replace snprintf & a max isa string length as suggested by Anup. 2. I have not included the Tested-by Tag from Heiko because the implementation changed from v2 to v3. Changes from v1->v2: 1. Improved the code redability by using arrays instead of individual check --- target/riscv/cpu.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index b0a40b83e7a8..2c7ff6ef555a 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -34,6 +34,12 @@ /* RISC-V CPU definitions */ +/* This includes the null terminated character '\0' */ +struct isa_ext_data { + const char *name; + bool enabled; +}; + static const char riscv_exts[26] = "IEMAFDQCLBJTPVNSUHKORWXYZG"; const char * const riscv_int_regnames[] = { @@ -881,6 +887,28 @@ static void riscv_cpu_class_init(ObjectClass *c, void *data) device_class_set_props(dc, riscv_cpu_properties); } +static void riscv_isa_string_ext(RISCVCPU *cpu, char **isa_str, int max_str_len) +{ + char *old = *isa_str; + char *new = *isa_str; + int i; + struct isa_ext_data isa_edata_arr[] = { + { "svpbmt", cpu->cfg.ext_svpbmt }, + { "svinval", cpu->cfg.ext_svinval }, + { "svnapot", cpu->cfg.ext_svnapot }, + }; + + for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) { + if (isa_edata_arr[i].enabled) { + new = g_strconcat(old, "_", isa_edata_arr[i].name, NULL); + g_free(old); + old = new; + } + } + + *isa_str = new; +} + char *riscv_isa_string(RISCVCPU *cpu) { int i; @@ -893,6 +921,7 @@ char *riscv_isa_string(RISCVCPU *cpu) } } *p = '\0'; + riscv_isa_string_ext(cpu, &isa_str, maxlen); return isa_str; } -- 2.30.2
