@@ -1,3 +1,4 @@
+obj-y += cpufeature.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-y += entry.o
obj-y += mm.o
new file mode 100644
@@ -0,0 +1,504 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Originally taken for Linux kernel v6.12-rc3.
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ * Copyright (C) 2017 SiFive
+ * Copyright (C) 2024 Vates
+ */
+
+#include <xen/bitmap.h>
+#include <xen/ctype.h>
+#include <xen/device_tree.h>
+#include <xen/errno.h>
+#include <xen/init.h>
+#include <xen/lib.h>
+#include <xen/sections.h>
+
+#include <asm/cpufeature.h>
+
+#ifdef CONFIG_ACPI
+# error "cpufeature.c functions should be updated to support ACPI"
+#endif
+
+struct riscv_isa_ext_data {
+ unsigned int id;
+ const char *name;
+};
+
+#define RISCV_ISA_EXT_DATA(ext_name) \
+{ \
+ .id = RISCV_ISA_EXT_ ## ext_name, \
+ .name = #ext_name, \
+}
+
+/* Host ISA bitmap */
+static __ro_after_init DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX);
+
+static int __init dt_get_cpuid_from_node(const struct dt_device_node *cpu,
+ unsigned long *dt_cpuid)
+{
+ const __be32 *prop;
+ unsigned int reg_len;
+
+ /*
+ * For debug purpose check dt_n_size_cells(cpu) value.
+ *
+ * Based on DT's bindings [1] and RISC-V's DTS files in kernel #size-cells
+ * for cpu node is expected to be 0.
+ *
+ * [1] https://www.kernel.org/doc/Documentation/devicetree/bindings/riscv/cpus.txt
+ */
+ if ( dt_n_size_cells(cpu) != 0 )
+ printk("DT's cpu node `%s`: #size-cells %d\n",
+ dt_node_full_name(cpu), dt_n_size_cells(cpu));
+
+ prop = dt_get_property(cpu, "reg", ®_len);
+ if ( !prop )
+ {
+ printk("cpu node `%s`: has no reg property\n", dt_node_full_name(cpu));
+ return -EINVAL;
+ }
+
+ if ( reg_len < dt_cells_to_size(dt_n_addr_cells(cpu)) )
+ {
+ printk("cpu node `%s`: reg property too short\n",
+ dt_node_full_name(cpu));
+ return -EINVAL;
+ }
+
+ /*
+ * It is safe to convert `paddr_t` to `unsigned long` as dt_read_paddr()
+ * in the context of this function returns cpuid which according to RISC-V
+ * specification could be from 0 to ((1ULL << (MXLEN)) - 1), where
+ * MXLEN=32 for RV32 and MXLEN=64 for RV64.
+ */
+ *dt_cpuid = dt_read_paddr(prop, dt_n_addr_cells(cpu));
+
+ return 0;
+}
+
+/*
+ * The canonical order of ISA extension names in the ISA string is defined in
+ * chapter 27 of the unprivileged specification.
+ *
+ * The specification uses vague wording, such as should, when it comes to
+ * ordering, so for our purposes the following rules apply:
+ *
+ * 1. All multi-letter extensions must be separated from other extensions by an
+ * underscore.
+ *
+ * 2. Additional standard extensions (starting with 'Z') must be sorted after
+ * single-letter extensions and before any higher-privileged extensions.
+ *
+ * 3. The first letter following the 'Z' conventionally indicates the most
+ * closely related alphabetical extension category, IMAFDQLCBKJTPVH.
+ * If multiple 'Z' extensions are named, they must be ordered first by
+ * category, then alphabetically within a category.
+ *
+ * 4. Standard supervisor-level extensions (starting with 'S') must be listed
+ * after standard unprivileged extensions. If multiple supervisor-level
+ * extensions are listed, they must be ordered alphabetically.
+ *
+ * 5. Standard machine-level extensions (starting with 'Zxm') must be listed
+ * after any lower-privileged, standard extensions. If multiple
+ * machine-level extensions are listed, they must be ordered
+ * alphabetically.
+ *
+ * 6. Non-standard extensions (starting with 'X') must be listed after all
+ * standard extensions. If multiple non-standard extensions are listed, they
+ * must be ordered alphabetically.
+ *
+ * An example string following the order is:
+ * rv64imadc_zifoo_zigoo_zafoo_sbar_scar_zxmbaz_xqux_xrux
+ *
+ * New entries to this struct should follow the ordering rules described above.
+ *
+ * Extension name must be all lowercase (according to device-tree binding)
+ * and strncmp() is used in match_isa_ext() to compare extension names instead
+ * of strncasecmp().
+ */
+const struct riscv_isa_ext_data __initconst riscv_isa_ext[] = {
+ RISCV_ISA_EXT_DATA(i),
+ RISCV_ISA_EXT_DATA(m),
+ RISCV_ISA_EXT_DATA(a),
+ RISCV_ISA_EXT_DATA(f),
+ RISCV_ISA_EXT_DATA(d),
+ RISCV_ISA_EXT_DATA(q),
+ RISCV_ISA_EXT_DATA(c),
+ RISCV_ISA_EXT_DATA(h),
+ RISCV_ISA_EXT_DATA(zicntr),
+ RISCV_ISA_EXT_DATA(zicsr),
+ RISCV_ISA_EXT_DATA(zifencei),
+ RISCV_ISA_EXT_DATA(zihintpause),
+ RISCV_ISA_EXT_DATA(zihpm),
+ RISCV_ISA_EXT_DATA(zba),
+ RISCV_ISA_EXT_DATA(zbb),
+ RISCV_ISA_EXT_DATA(zbs),
+ RISCV_ISA_EXT_DATA(smaia),
+ RISCV_ISA_EXT_DATA(ssaia),
+};
+
+static const struct riscv_isa_ext_data __initconst required_extensions[] = {
+ RISCV_ISA_EXT_DATA(i),
+ RISCV_ISA_EXT_DATA(m),
+ RISCV_ISA_EXT_DATA(a),
+#ifdef CONFIG_RISCV_ISA_C
+ RISCV_ISA_EXT_DATA(c),
+#endif
+ RISCV_ISA_EXT_DATA(zicsr),
+ RISCV_ISA_EXT_DATA(zifencei),
+ RISCV_ISA_EXT_DATA(zihintpause),
+ RISCV_ISA_EXT_DATA(zbb),
+};
+
+static bool __init is_lowercase_extension_name(const char *str)
+{
+ /*
+ * `str` could contain full riscv,isa string from device tree so one
+ * of the stop conditions is checking for '_' as extensions are
+ * separated by '_'.
+ */
+ for ( unsigned int i = 0; (str[i] != '\0') && (str[i] != '_'); i++ )
+ if ( !isdigit(str[i]) && !islower(str[i]) )
+ return false;
+
+ return true;
+}
+
+static void __init match_isa_ext(const char *name, const char *name_end,
+ unsigned long *bitmap)
+{
+ const size_t riscv_isa_ext_count = ARRAY_SIZE(riscv_isa_ext);
+
+ for ( unsigned int i = 0; i < riscv_isa_ext_count; i++ )
+ {
+ const struct riscv_isa_ext_data *ext = &riscv_isa_ext[i];
+
+ /*
+ * `ext->name` (according to initialization of riscv_isa_ext[]
+ * elements) must be all in lowercase.
+ */
+ ASSERT(is_lowercase_extension_name(ext->name));
+
+ if ( (name_end - name == strlen(ext->name)) &&
+ !memcmp(name, ext->name, name_end - name) )
+ {
+ __set_bit(ext->id, bitmap);
+ break;
+ }
+ }
+}
+
+static int __init riscv_isa_parse_string(const char *isa,
+ unsigned long *out_bitmap)
+{
+ if ( (isa[0] != 'r') && (isa[1] != 'v') )
+ return -EINVAL;
+
+#if defined(CONFIG_RISCV_32)
+ if ( isa[2] != '3' && isa[3] != '2' )
+ return -EINVAL;
+#elif defined(CONFIG_RISCV_64)
+ if ( isa[2] != '6' && isa[3] != '4' )
+ return -EINVAL;
+#else
+# error "unsupported RISC-V bitness"
+#endif
+
+ /*
+ * In unpriv. specification (*_20240411) is mentioned the following:
+ * (1) A RISC-V ISA is defined as a base integer ISA, which must be
+ * present in any implementation, plus optional extensions to
+ * the base ISA.
+ * (2) Chapter 6 describes the RV32E and RV64E subset variants of
+ * the RV32I or RV64I base instruction sets respectively, which
+ * have been added to support small microcontrollers, and which
+ * have half the number of integer registers.
+ *
+ * What means that isa should contain, at least, I or E.
+ *
+ * As Xen isn't expected to be run on microcontrollers and according
+ * to device tree binding the first extension should be "i".
+ */
+ if ( isa[4] != 'i' )
+ return -EINVAL;
+
+ isa += 4;
+
+ while ( *isa )
+ {
+ const char *ext = isa++;
+ const char *ext_end = isa;
+
+ switch ( *ext )
+ {
+ case 'x':
+ printk_once("Vendor extensions are ignored in riscv,isa\n");
+ /*
+ * To skip an extension, we find its end.
+ * As multi-letter extensions must be split from other multi-letter
+ * extensions with an "_", the end of a multi-letter extension will
+ * either be the null character or the "_" at the start of the next
+ * multi-letter extension.
+ */
+ for ( ; *isa && *isa != '_'; ++isa )
+ if ( unlikely(!isalnum(*isa)) )
+ goto riscv_isa_parse_string_err;
+
+ ext_end = NULL;
+ break;
+
+ case 's':
+ /*
+ * Workaround for invalid single-letter 's' & 'u' (QEMU):
+ * Before QEMU 7.1 it was an issue with misa to ISA string
+ * conversion:
+ * https://patchwork.kernel.org/project/qemu-devel/patch/dee09d708405075420b29115c1e9e87910b8da55.1648270894.git.research_trasio@irq.a4lg.com/#24792587
+ * Additional details of the workaround on Linux kernel side:
+ * https://lore.kernel.org/linux-riscv/ae93358e-e117-b43d-faad-772c529f846c@irq.a4lg.com/#t
+ *
+ * No need to set the bit in riscv_isa as 's' & 'u' are
+ * not valid ISA extensions. It works unless the first
+ * multi-letter extension in the ISA string begins with
+ * "Su" and is not prefixed with an underscore.
+ */
+ if ( ext[-1] != '_' && ext[1] == 'u' )
+ {
+ ++isa;
+ ext_end = NULL;
+ break;
+ }
+ fallthrough;
+ case 'z':
+ /*
+ * Before attempting to parse the extension itself, we find its end.
+ * As multi-letter extensions must be split from other multi-letter
+ * extensions with an "_", the end of a multi-letter extension will
+ * either be the null character or the "_" at the start of the next
+ * multi-letter extension.
+ *
+ * Next, as the extensions version is currently ignored, we
+ * eliminate that portion. This is done by parsing backwards from
+ * the end of the extension, removing any numbers. This may be a
+ * major or minor number however, so the process is repeated if a
+ * minor number was found.
+ *
+ * ext_end is intended to represent the first character *after* the
+ * name portion of an extension, but will be decremented to the last
+ * character itself while eliminating the extensions version number.
+ * A simple re-increment solves this problem.
+ */
+ for ( ; *isa && *isa != '_'; ++isa )
+ if ( unlikely(!isalnum(*isa)) )
+ goto riscv_isa_parse_string_err;
+
+ ext_end = isa;
+
+ if ( !isdigit(ext_end[-1]) )
+ break;
+
+ while ( isdigit(*--ext_end) )
+ ;
+
+ if ( ext_end[0] != 'p' || !isdigit(ext_end[-1]) )
+ {
+ ++ext_end;
+ break;
+ }
+
+ while ( isdigit(*--ext_end) )
+ ;
+
+ ++ext_end;
+ break;
+
+ /*
+ * If someone mentioned `b` extension in riscv,isa instead of Zb{a,b,s}
+ * explicitly then set bits exlicitly in out_bitmap to satisfy
+ * requirement of Zbb (mentioned in required_extensions[]).
+ */
+ case 'b':
+ __set_bit(RISCV_ISA_EXT_zba, out_bitmap);
+ __set_bit(RISCV_ISA_EXT_zbb, out_bitmap);
+ __set_bit(RISCV_ISA_EXT_zbs, out_bitmap);
+ fallthrough;
+ default:
+ /*
+ * Things are a little easier for single-letter extensions, as they
+ * are parsed forwards.
+ *
+ * After checking that our starting position is valid, we need to
+ * ensure that, when isa was incremented at the start of the loop,
+ * that it arrived at the start of the next extension.
+ *
+ * If we are already on a non-digit, there is nothing to do. Either
+ * we have a multi-letter extension's _, or the start of an
+ * extension.
+ *
+ * Otherwise we have found the current extension's major version
+ * number. Parse past it, and a subsequent p/minor version number
+ * if present. The `p` extension must not appear immediately after
+ * a number, so there is no fear of missing it.
+ */
+ if ( unlikely(!isalpha(*ext)) )
+ goto riscv_isa_parse_string_err;
+
+ if ( !isdigit(*isa) )
+ break;
+
+ while ( isdigit(*++isa) )
+ ;
+
+ if ( *isa != 'p' )
+ break;
+
+ if ( !isdigit(*++isa) )
+ {
+ --isa;
+ break;
+ }
+
+ while ( isdigit(*++isa) )
+ ;
+
+ break;
+ }
+
+ /*
+ * The parser expects that at the start of an iteration isa points to the
+ * first character of the next extension. As we stop parsing an extension
+ * on meeting a non-alphanumeric character, an extra increment is needed
+ * where the succeeding extension is a multi-letter prefixed with an "_".
+ */
+ if ( *isa == '_' )
+ ++isa;
+
+ if ( unlikely(!ext_end) )
+ continue;
+
+ match_isa_ext(ext, ext_end, out_bitmap);
+ }
+
+ return 0;
+
+ riscv_isa_parse_string_err:
+ printk("illegal symbol '%c' in riscv,isa string\n", *isa);
+ return -EINVAL;
+}
+
+static void __init riscv_fill_hwcap_from_isa_string(void)
+{
+ const struct dt_device_node *cpus = dt_find_node_by_path("/cpus");
+ const struct dt_device_node *cpu;
+
+ if ( !cpus )
+ {
+ printk("Missing /cpus node in the device tree?\n");
+ return;
+ }
+
+ dt_for_each_child_node(cpus, cpu)
+ {
+ DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
+ const char *isa;
+ unsigned long cpuid;
+
+ if ( !dt_device_type_is_equal(cpu, "cpu") )
+ continue;
+
+ if ( dt_get_cpuid_from_node(cpu, &cpuid) < 0 )
+ continue;
+
+ if ( dt_property_read_string(cpu, "riscv,isa", &isa) )
+ {
+ printk("Unable to find \"riscv,isa\" devicetree entry "
+ "for DT's cpu%ld node\n", cpuid);
+ continue;
+ }
+
+ for ( unsigned int i = 0; (isa[i] != '\0'); i++ )
+ if ( !isdigit(isa[i]) && (isa[i] != '_') && !islower(isa[i]) )
+ panic("According to DT binding riscv,isa must be lowercase\n");
+
+ if ( riscv_isa_parse_string(isa, this_isa) )
+ panic("Check riscv,isa in dts file\n");
+
+ if ( bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX) )
+ bitmap_copy(riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
+ else
+ bitmap_and(riscv_isa, riscv_isa, this_isa, RISCV_ISA_EXT_MAX);
+ }
+}
+
+static bool __init has_isa_extensions_property(void)
+{
+ const struct dt_device_node *cpus = dt_find_node_by_path("/cpus");
+ const struct dt_device_node *cpu;
+
+ if ( !cpus )
+ {
+ printk("Missing /cpus node in the device tree?\n");
+ return false;
+ }
+
+ dt_for_each_child_node(cpus, cpu)
+ {
+ const char *isa;
+
+ if ( !dt_device_type_is_equal(cpu, "cpu") )
+ continue;
+
+ if ( dt_property_read_string(cpu, "riscv,isa-extensions", &isa) )
+ continue;
+
+ return true;
+ }
+
+ return false;
+}
+
+bool riscv_isa_extension_available(const unsigned long *isa_bitmap,
+ enum riscv_isa_ext_id id)
+{
+ if ( !isa_bitmap )
+ isa_bitmap = riscv_isa;
+
+ if ( id >= RISCV_ISA_EXT_MAX )
+ return false;
+
+ return test_bit(id, isa_bitmap);
+}
+
+void __init riscv_fill_hwcap(void)
+{
+ unsigned int i;
+ const size_t req_extns_amount = ARRAY_SIZE(required_extensions);
+ bool all_extns_available = true;
+
+ riscv_fill_hwcap_from_isa_string();
+
+ if ( bitmap_empty(riscv_isa, RISCV_ISA_EXT_MAX) )
+ {
+ const char *failure_msg = has_isa_extensions_property() ?
+ "\"riscv,isa-extension\" isn't supported" :
+ "\"riscv,isa\" parsing failed";
+
+ panic("HW capabilities parsing failed: %s\n", failure_msg);
+ }
+
+ for ( i = 0; i < req_extns_amount; i++ )
+ {
+ const struct riscv_isa_ext_data ext = required_extensions[i];
+
+ if ( !riscv_isa_extension_available(NULL, ext.id) )
+ {
+ printk("Xen requires extension: %s\n", ext.name);
+ all_extns_available = false;
+ }
+ }
+
+ if ( !all_extns_available )
+ panic("Look why the extensions above are needed in "
+ "https://xenbits.xenproject.org/docs/unstable/misc/riscv/booting.txt\n");
+}
new file mode 100644
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef ASM__RISCV__CPUFEATURE_H
+#define ASM__RISCV__CPUFEATURE_H
+
+#ifndef __ASSEMBLY__
+
+#include <xen/stdbool.h>
+
+/*
+ * These macros represent the logical IDs of each multi-letter RISC-V ISA
+ * extension and are used in the ISA bitmap. The logical IDs start from
+ * RISCV_ISA_EXT_BASE, which allows the 0-25 range to be reserved for single
+ * letter extensions and are used in enum riscv_isa_ext_id.
+ *
+ * New extensions should just be added to the bottom, rather than added
+ * alphabetically, in order to avoid unnecessary shuffling.
+ */
+#define RISCV_ISA_EXT_BASE 26
+
+enum riscv_isa_ext_id {
+ RISCV_ISA_EXT_a,
+ RISCV_ISA_EXT_c,
+ RISCV_ISA_EXT_d,
+ RISCV_ISA_EXT_f,
+ RISCV_ISA_EXT_h,
+ RISCV_ISA_EXT_i,
+ RISCV_ISA_EXT_m,
+ RISCV_ISA_EXT_q,
+ RISCV_ISA_EXT_v,
+ RISCV_ISA_EXT_zicntr = RISCV_ISA_EXT_BASE,
+ RISCV_ISA_EXT_zicsr,
+ RISCV_ISA_EXT_zifencei,
+ RISCV_ISA_EXT_zihintpause,
+ RISCV_ISA_EXT_zihpm,
+ RISCV_ISA_EXT_zba,
+ RISCV_ISA_EXT_zbb,
+ RISCV_ISA_EXT_zbs,
+ RISCV_ISA_EXT_smaia,
+ RISCV_ISA_EXT_ssaia,
+ RISCV_ISA_EXT_MAX
+};
+
+void riscv_fill_hwcap(void);
+
+bool riscv_isa_extension_available(const unsigned long *isa_bitmap,
+ enum riscv_isa_ext_id id);
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* ASM__RISCV__CPUFEATURE_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
@@ -13,6 +13,7 @@
#include <public/version.h>
+#include <asm/cpufeature.h>
#include <asm/early_printk.h>
#include <asm/fixmap.h>
#include <asm/sbi.h>
@@ -123,6 +124,8 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
panic("Booting using ACPI isn't supported\n");
}
+ riscv_fill_hwcap();
+
printk("All set up\n");
machine_halt();