[PATCH 4/6] lib: sbi: Add detection of Smepmp from ISA string in FDT
Anup Patel
anup at brainfault.org
Tue Jul 4 06:18:54 PDT 2023
On Tue, Jun 20, 2023 at 8:02 PM Himanshu Chauhan
<hchauhan at ventanamicro.com> wrote:
>
> - To enable Smepmp, the ISA string in FDT should have "smepmp" string. This patch
> adds support for parsing of Smepmp in ISA string.
> - A bit is reserved for Smepmp in extensions member of sbi_hart_features
> which is set if Smepmp is detected in FDT.
> - A utilty function is added to check if Smepmp is detected and enabled.
> - In sbi_boot_print_hart, a print is added to display the state of Smepmp.
>
> Signed-off-by: Himanshu Chauhan <hchauhan at ventanamicro.com>
This patch needs to be broken down into two PATCHs:
1) Add SBI_HART_EXT_SMEPMP in include/sbi/sbi_hart.h and
lib/sbi/sbi_hart.c
2) Add ISA parsing in include/sbi_utils/fdt/fdt_helper.h,
lib/utils/fdt/fdt_helper.c, and platform/generic/platform.c
See below for more comments...
> ---
> include/sbi/sbi_hart.h | 3 +
> include/sbi_utils/fdt/fdt_helper.h | 3 +
> lib/sbi/sbi_hart.c | 8 +++
> lib/sbi/sbi_init.c | 2 +
> lib/utils/fdt/fdt_helper.c | 111 +++++++++++++++++++++++++++++
> platform/generic/platform.c | 5 ++
> 6 files changed, 132 insertions(+)
>
> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> index 95b40e7..9582b52 100644
> --- a/include/sbi/sbi_hart.h
> +++ b/include/sbi/sbi_hart.h
> @@ -36,6 +36,8 @@ enum sbi_hart_extensions {
> SBI_HART_EXT_SMSTATEEN,
> /** HART has Sstc extension */
> SBI_HART_EXT_SSTC,
> + /** HART has Smepmp */
> + SBI_HART_EXT_SMEPMP,
>
> /** Maximum index of Hart extension */
> SBI_HART_EXT_MAX,
> @@ -66,6 +68,7 @@ static inline ulong sbi_hart_expected_trap_addr(void)
> unsigned int sbi_hart_mhpm_count(struct sbi_scratch *scratch);
> void sbi_hart_delegation_dump(struct sbi_scratch *scratch,
> const char *prefix, const char *suffix);
> +unsigned int sbi_hart_smepmp_supported(struct sbi_scratch *scratch);
This is is not needed because sbi_hart_has_extension() does the same thing.
> unsigned int sbi_hart_pmp_count(struct sbi_scratch *scratch);
> unsigned long sbi_hart_pmp_granularity(struct sbi_scratch *scratch);
> unsigned int sbi_hart_pmp_addrbits(struct sbi_scratch *scratch);
> diff --git a/include/sbi_utils/fdt/fdt_helper.h b/include/sbi_utils/fdt/fdt_helper.h
> index 39d7f3a..5c928ff 100644
> --- a/include/sbi_utils/fdt/fdt_helper.h
> +++ b/include/sbi_utils/fdt/fdt_helper.h
> @@ -56,6 +56,9 @@ int fdt_parse_max_enabled_hart_id(void *fdt, u32 *max_hartid);
>
> int fdt_parse_timebase_frequency(void *fdt, unsigned long *freq);
>
> +int fdt_parse_isa_extensions(void *fdt, unsigned int hard_id,
> + unsigned long *extensions);
> +
> int fdt_parse_gaisler_uart_node(void *fdt, int nodeoffset,
> struct platform_uart_data *uart);
>
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 6e52cbd..c328243 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -260,6 +260,14 @@ unsigned int sbi_hart_pmp_count(struct sbi_scratch *scratch)
> return hfeatures->pmp_count;
> }
>
> +unsigned int sbi_hart_smepmp_supported(struct sbi_scratch *scratch)
> +{
> + struct sbi_hart_features *hfeatures =
> + sbi_scratch_offset_ptr(scratch, hart_features_offset);
> +
> + return !!(hfeatures->extensions & (_UL(1) << SBI_HART_EXT_SMEPMP));
> +}
> +
Drop this function since sbi_hart_has_extension() does the same thing.
You missed adding "smepmp" in the sbi_hart_extension_id2string() function.
> unsigned long sbi_hart_pmp_granularity(struct sbi_scratch *scratch)
> {
> struct sbi_hart_features *hfeatures =
> diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
> index 423e6d8..31d2c3e 100644
> --- a/lib/sbi/sbi_init.c
> +++ b/lib/sbi/sbi_init.c
> @@ -173,6 +173,8 @@ static void sbi_boot_print_hart(struct sbi_scratch *scratch, u32 hartid)
> misa_string(xlen, str, sizeof(str));
> sbi_printf("Boot HART Base ISA : %s\n", str);
> sbi_hart_get_extensions_str(scratch, str, sizeof(str));
> + sbi_printf("SMEPMP : %sDetected\n",
> + (sbi_hart_smepmp_supported(scratch) ? "" : "Not "));
No need for this because sbi_hart_extension_id2string() will ensure that
"smepmp" is printed as a "Boot HART ISA Extensions".
> sbi_printf("Boot HART ISA Extensions : %s\n", str);
> sbi_printf("Boot HART PMP Count : %d\n",
> sbi_hart_pmp_count(scratch));
> diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c
> index a88a4ba..db9d4c3 100644
> --- a/lib/utils/fdt/fdt_helper.c
> +++ b/lib/utils/fdt/fdt_helper.c
> @@ -12,6 +12,7 @@
> #include <sbi/sbi_hartmask.h>
> #include <sbi/sbi_platform.h>
> #include <sbi/sbi_scratch.h>
> +#include <sbi/sbi_hart.h> /* for hart extension enums */
No need for the "/* */" comment.
> #include <sbi_utils/fdt/fdt_helper.h>
> #include <sbi_utils/irqchip/aplic.h>
> #include <sbi_utils/irqchip/imsic.h>
> @@ -313,6 +314,116 @@ int fdt_parse_timebase_frequency(void *fdt, unsigned long *freq)
> return 0;
> }
>
> +static int fdt_get_isa_string(void *fdt, unsigned int hartid,
> + const char **isa_string)
> +{
> + int err, cpu_offset, cpus_offset, len;
> + u32 c_hartid;
> + const fdt32_t *val;
> +
> + if (!fdt)
> + return SBI_EINVAL;
> +
> + cpus_offset = fdt_path_offset(fdt, "/cpus");
> + if (cpus_offset < 0)
> + return cpus_offset;
> +
> + fdt_for_each_subnode(cpu_offset, fdt, cpus_offset) {
> + err = fdt_parse_hart_id(fdt, cpu_offset, &c_hartid);
> + if (err)
> + continue;
> +
> + if (!fdt_node_is_enabled(fdt, cpu_offset))
> + continue;
> +
> + if (c_hartid == hartid) {
> + val = fdt_getprop(fdt, cpu_offset, "riscv,isa", &len);
> + if (val && len > 0) {
> + *isa_string = (const char *)val;
> + return 0;
> + }
> + }
> + }
> +
> + return SBI_EINVAL;
> +}
> +
> +#define RISCV_ISA_EXT_NAME_LEN_MAX 32
> +
> +int fdt_parse_isa_extensions(void *fdt, unsigned int hartid,
> + unsigned long *extensions)
> +{
> + size_t i, j, isa_len;
> + char mstr[RISCV_ISA_EXT_NAME_LEN_MAX];
> + const char *isa = NULL;
> +
> + if (fdt_get_isa_string(fdt, hartid, &isa))
> + return SBI_EINVAL;
> +
> + if (!isa)
> + return SBI_EINVAL;
> +
> + i = 0;
> + isa_len = strlen(isa);
> +
> + if (isa[i] == 'r' || isa[i] == 'R')
> + i++;
> + else
> + return SBI_EINVAL;
> +
> + if (isa[i] == 'v' || isa[i] == 'V')
> + i++;
> + else
> + return SBI_EINVAL;
> +
> + if (isa[i] == '3' || isa[i+1] == '2')
> + i += 2;
> + else if (isa[i] == '6' || isa[i+1] == '4')
> + i += 2;
> + else
> + return SBI_EINVAL;
> +
> + /* Skip base ISA extentions */
s/extentions/extensions/
> + for (; i < isa_len; i++) {
> + if (isa[i] == '_')
> + break;
> + }
> +
> + while (i < isa_len) {
> + if (isa[i] != '_') {
> + i++;
> + continue;
> + }
> +
> + /* Skip the '_' character */
> + i++;
> +
> + /* Extract the multi-letter extension name */
> + j = 0;
> + while ((i < isa_len) && (isa[i] != '_') &&
> + (j < (sizeof(mstr) - 1)))
> + mstr[j++] = isa[i++];
> + mstr[j] = '\0';
> +
> + /* Skip empty multi-letter extension name */
> + if (!j)
> + continue;
> +
> +#define SET_ISA_EXT_MAP(name, bit) \
> + do { \
> + if (!strcmp(mstr, name)) { \
> + __set_bit(bit, extensions); \
> + continue; \
> + } \
> + } while (false) \
> +
> + SET_ISA_EXT_MAP("smepmp", SBI_HART_EXT_SMEPMP);
> +#undef SET_ISA_EXT_MAP
> + }
> +
> + return 0;
> +}
> +
> static int fdt_parse_uart_node_common(void *fdt, int nodeoffset,
> struct platform_uart_data *uart,
> unsigned long default_freq,
> diff --git a/platform/generic/platform.c b/platform/generic/platform.c
> index 0c9cd95..24c0fa9 100644
> --- a/platform/generic/platform.c
> +++ b/platform/generic/platform.c
> @@ -215,6 +215,11 @@ static int generic_extensions_init(struct sbi_hart_features *hfeatures)
> return generic_plat->extensions_init(generic_plat_match,
> hfeatures);
>
> + /* Parse the ISA string from FDT and enable the listed extensions */
> + if (fdt_parse_isa_extensions(fdt_get_address(), current_hartid(),
> + &hfeatures->extensions))
> + return 0;
> +
This needs to be done before generic_plat->extensions_init() because
code will not reach here if platform_override has extensions_init() callback.
Add following lines before generic_plat->extensions_init()
rc = fdt_parse_isa_extensions(fdt_get_address(), current_hartid(),
&hfeatures->extensions));
if (rc)
return rc;
> return 0;
> }
>
> --
> 2.34.1
>
>
> --
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Regards,
Anup
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