bsd-user: Comprehensive RISCV support

[PATCH 06/18] bsd-user: Add RISC-V ELF definitions and hardware capability detection

Posted by Ajeet Singh 3 months, 3 weeks ago

From: Mark Corbin <mark.corbin@embecsom.com>

Introduced RISC-V specific ELF definitions and hardware capability
detection.
Additionally, a function to retrieve hardware capabilities
('get_elf_hwcap') is implemented, which returns the common bits set in
each CPU's ISA strings.

Signed-off-by: Mark Corbin <mark.corbin@embecsom.com>
Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
Co-authored-by: Kyle Evans <kevans@FreeBSD.org>
---
 bsd-user/riscv/target_arch_elf.h | 48 ++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 bsd-user/riscv/target_arch_elf.h

diff --git a/bsd-user/riscv/target_arch_elf.h b/bsd-user/riscv/target_arch_elf.h
new file mode 100644
index 0000000000..dfb2a3e32e
--- /dev/null
+++ b/bsd-user/riscv/target_arch_elf.h
@@ -0,0 +1,48 @@
+/*
+ *  RISC-V ELF definitions
+ *
+ *  Copyright (c) 2019 Mark Corbin
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TARGET_ARCH_ELF_H
+#define TARGET_ARCH_ELF_H
+
+#define elf_check_arch(x) ((x) == EM_RISCV)
+#define ELF_START_MMAP 0x80000000
+#define ELF_ET_DYN_LOAD_ADDR    0x100000
+#define ELF_CLASS   ELFCLASS64
+
+#define ELF_DATA    ELFDATA2LSB
+#define ELF_ARCH    EM_RISCV
+
+/*
+ * Note: FreeBSD returns things a litle differently than this, but this is as
+ * close we have in the emulator. The FreeBSD/riscv64 kernel (in identcpu.c)
+ * returns the common bits set in each of the CPUs' ISA strings. Also, unlike
+ * linux, we don't mask out specific bits.
+ */
+#define ELF_HWCAP get_elf_hwcap()
+static uint32_t get_elf_hwcap(void)
+{
+    RISCVCPU *cpu = RISCV_CPU(thread_cpu);
+
+    return cpu->env.misa_ext_mask;
+}
+
+#define USE_ELF_CORE_DUMP
+#define ELF_EXEC_PAGESIZE        4096
+
+#endif /* TARGET_ARCH_ELF_H */
-- 
2.34.1

Re: [PATCH 06/18] bsd-user: Add RISC-V ELF definitions and hardware capability detection

Posted by Richard Henderson 3 months, 3 weeks ago

On 8/2/24 18:34, Ajeet Singh wrote:
> From: Mark Corbin <mark.corbin@embecsom.com>
> 
> Introduced RISC-V specific ELF definitions and hardware capability
> detection.
> Additionally, a function to retrieve hardware capabilities
> ('get_elf_hwcap') is implemented, which returns the common bits set in
> each CPU's ISA strings.
> 
> Signed-off-by: Mark Corbin <mark.corbin@embecsom.com>
> Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
> Co-authored-by: Kyle Evans <kevans@FreeBSD.org>
> ---
>   bsd-user/riscv/target_arch_elf.h | 48 ++++++++++++++++++++++++++++++++
>   1 file changed, 48 insertions(+)
>   create mode 100644 bsd-user/riscv/target_arch_elf.h
> 
> diff --git a/bsd-user/riscv/target_arch_elf.h b/bsd-user/riscv/target_arch_elf.h
> new file mode 100644
> index 0000000000..dfb2a3e32e
> --- /dev/null
> +++ b/bsd-user/riscv/target_arch_elf.h
> @@ -0,0 +1,48 @@
> +/*
> + *  RISC-V ELF definitions
> + *
> + *  Copyright (c) 2019 Mark Corbin
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef TARGET_ARCH_ELF_H
> +#define TARGET_ARCH_ELF_H
> +
> +#define elf_check_arch(x) ((x) == EM_RISCV)
> +#define ELF_START_MMAP 0x80000000
> +#define ELF_ET_DYN_LOAD_ADDR    0x100000
> +#define ELF_CLASS   ELFCLASS64
> +
> +#define ELF_DATA    ELFDATA2LSB
> +#define ELF_ARCH    EM_RISCV
> +
> +/*
> + * Note: FreeBSD returns things a litle differently than this, but this is as
> + * close we have in the emulator. The FreeBSD/riscv64 kernel (in identcpu.c)
> + * returns the common bits set in each of the CPUs' ISA strings. Also, unlike
> + * linux, we don't mask out specific bits.

Given that all user-only cpus are identical, all bits are common.
So this really is identical to the freebsd kernel.

I think that this comment is more confusing than illuminating.

Otherwise,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~