Re: [PATCH v2 12/12] hw/riscv: spike: Decouple create_fdt() dependency to ELF loading

[Alistair Francis]

On Thu, Dec 29, 2022 at 8:33 PM Bin Meng <bmeng@tinylab.org> wrote:
>
> At present create_fdt() calls htif_uses_elf_symbols() to determine
> whether to insert a <reg> property for the HTIF. This unfortunately
> creates a hidden dependency to riscv_load_{firmware,kernel} that
> create_fdt() must be called after the ELF {firmware,kernel} image
> has been loaded.
>
> Decouple such dependency be adding a new parameter to create_fdt(),
> whether custom HTIF base address is used. The flag will be set if
> non ELF {firmware,kernel} image is given by user.
>
> Signed-off-by: Bin Meng <bmeng@tinylab.org>

Thanks!

Applied to riscv-to-apply.next

Alistair

>
> ---
>
> Changes in v2:
> - initialize firmware_end_addr to memmap[SPIKE_DRAM].base
> - rework the htif_custom_base detection logic
>
>  include/hw/char/riscv_htif.h |  5 +--
>  hw/char/riscv_htif.c         | 17 +++++-----
>  hw/riscv/spike.c             | 61 ++++++++++++++++++++++++++++++------
>  3 files changed, 59 insertions(+), 24 deletions(-)
>
> diff --git a/include/hw/char/riscv_htif.h b/include/hw/char/riscv_htif.h
> index 9e8ebbe017..5958c5b986 100644
> --- a/include/hw/char/riscv_htif.h
> +++ b/include/hw/char/riscv_htif.h
> @@ -44,11 +44,8 @@ typedef struct HTIFState {
>  void htif_symbol_callback(const char *st_name, int st_info, uint64_t 
> st_value,
>      uint64_t st_size);
>
> -/* Check if HTIF uses ELF symbols */
> -bool htif_uses_elf_symbols(void);
> -
>  /* legacy pre qom */
>  HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
> -                        uint64_t nonelf_base);
> +                        uint64_t nonelf_base, bool custom_base);
>
>  #endif
> diff --git a/hw/char/riscv_htif.c b/hw/char/riscv_htif.c
> index 1477fc0090..098de50e35 100644
> --- a/hw/char/riscv_htif.c
> +++ b/hw/char/riscv_htif.c
> @@ -52,20 +52,17 @@
>  #define PK_SYS_WRITE            64
>
>  static uint64_t fromhost_addr, tohost_addr;
> -static int address_symbol_set;
>
>  void htif_symbol_callback(const char *st_name, int st_info, uint64_t 
> st_value,
>                            uint64_t st_size)
>  {
>      if (strcmp("fromhost", st_name) == 0) {
> -        address_symbol_set |= 1;
>          fromhost_addr = st_value;
>          if (st_size != 8) {
>              error_report("HTIF fromhost must be 8 bytes");
>              exit(1);
>          }
>      } else if (strcmp("tohost", st_name) == 0) {
> -        address_symbol_set |= 2;
>          tohost_addr = st_value;
>          if (st_size != 8) {
>              error_report("HTIF tohost must be 8 bytes");
> @@ -275,19 +272,19 @@ static const MemoryRegionOps htif_mm_ops = {
>      .write = htif_mm_write,
>  };
>
> -bool htif_uses_elf_symbols(void)
> -{
> -    return (address_symbol_set == 3) ? true : false;
> -}
> -
>  HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
> -                        uint64_t nonelf_base)
> +                        uint64_t nonelf_base, bool custom_base)
>  {
>      uint64_t base, size, tohost_offset, fromhost_offset;
>
> -    if (!htif_uses_elf_symbols()) {
> +    if (custom_base) {
>          fromhost_addr = nonelf_base;
>          tohost_addr = nonelf_base + 8;
> +    } else {
> +        if (!fromhost_addr || !tohost_addr) {
> +            error_report("Invalid HTIF fromhost or tohost address");
> +            exit(1);
> +        }
>      }
>
>      base = MIN(tohost_addr, fromhost_addr);
> diff --git a/hw/riscv/spike.c b/hw/riscv/spike.c
> index 810a18f283..dd5f912e3d 100644
> --- a/hw/riscv/spike.c
> +++ b/hw/riscv/spike.c
> @@ -50,7 +50,8 @@ static const MemMapEntry spike_memmap[] = {
>  };
>
>  static void create_fdt(SpikeState *s, const MemMapEntry *memmap,
> -                       uint64_t mem_size, const char *cmdline, bool 
> is_32_bit)
> +                       uint64_t mem_size, const char *cmdline,
> +                       bool is_32_bit, bool htif_custom_base)
>  {
>      void *fdt;
>      uint64_t addr, size;
> @@ -78,7 +79,7 @@ static void create_fdt(SpikeState *s, const MemMapEntry 
> *memmap,
>
>      qemu_fdt_add_subnode(fdt, "/htif");
>      qemu_fdt_setprop_string(fdt, "/htif", "compatible", "ucb,htif0");
> -    if (!htif_uses_elf_symbols()) {
> +    if (htif_custom_base) {
>          qemu_fdt_setprop_cells(fdt, "/htif", "reg",
>              0x0, memmap[SPIKE_HTIF].base, 0x0, memmap[SPIKE_HTIF].size);
>      }
> @@ -184,18 +185,33 @@ static void create_fdt(SpikeState *s, const MemMapEntry 
> *memmap,
>      }
>  }
>
> +static bool spike_test_elf_image(char *filename)
> +{
> +    Error *err = NULL;
> +
> +    load_elf_hdr(filename, NULL, NULL, &err);
> +    if (err) {
> +        error_free(err);
> +        return false;
> +    } else {
> +        return true;
> +    }
> +}
> +
>  static void spike_board_init(MachineState *machine)
>  {
>      const MemMapEntry *memmap = spike_memmap;
>      SpikeState *s = SPIKE_MACHINE(machine);
>      MemoryRegion *system_memory = get_system_memory();
>      MemoryRegion *mask_rom = g_new(MemoryRegion, 1);
> -    target_ulong firmware_end_addr, kernel_start_addr;
> -    const char *firmware_name;
> +    target_ulong firmware_end_addr = memmap[SPIKE_DRAM].base;
> +    target_ulong kernel_start_addr;
> +    char *firmware_name;
>      uint32_t fdt_load_addr;
>      uint64_t kernel_entry;
>      char *soc_name;
>      int i, base_hartid, hart_count;
> +    bool htif_custom_base = false;
>
>      /* Check socket count limit */
>      if (SPIKE_SOCKETS_MAX < riscv_socket_count(machine)) {
> @@ -257,10 +273,34 @@ static void spike_board_init(MachineState *machine)
>      memory_region_add_subregion(system_memory, memmap[SPIKE_MROM].base,
>                                  mask_rom);
>
> -    firmware_name = riscv_default_firmware_name(&s->soc[0]);
> -    firmware_end_addr = riscv_find_and_load_firmware(machine, firmware_name,
> -                                                     memmap[SPIKE_DRAM].base,
> -                                                     htif_symbol_callback);
> +    /* Find firmware */
> +    firmware_name = riscv_find_firmware(machine->firmware,
> +                        riscv_default_firmware_name(&s->soc[0]));
> +
> +    /*
> +     * Test the given firmware or kernel file to see if it is an ELF image.
> +     * If it is an ELF, we assume it contains the symbols required for
> +     * the HTIF console, otherwise we fall back to use the custom base
> +     * passed from device tree for the HTIF console.
> +     */
> +    if (!firmware_name && !machine->kernel_filename) {
> +        htif_custom_base = true;
> +    } else {
> +        if (firmware_name) {
> +            htif_custom_base = !spike_test_elf_image(firmware_name);
> +        }
> +        if (!htif_custom_base && machine->kernel_filename) {
> +            htif_custom_base = 
> !spike_test_elf_image(machine->kernel_filename);
> +        }
> +    }
> +
> +    /* Load firmware */
> +    if (firmware_name) {
> +        firmware_end_addr = riscv_load_firmware(firmware_name,
> +                                                memmap[SPIKE_DRAM].base,
> +                                                htif_symbol_callback);
> +        g_free(firmware_name);
> +    }
>
>      /* Load kernel */
>      if (machine->kernel_filename) {
> @@ -280,7 +320,7 @@ static void spike_board_init(MachineState *machine)
>
>      /* Create device tree */
>      create_fdt(s, memmap, machine->ram_size, machine->kernel_cmdline,
> -               riscv_is_32bit(&s->soc[0]));
> +               riscv_is_32bit(&s->soc[0]), htif_custom_base);
>
>      /* Load initrd */
>      if (machine->kernel_filename && machine->initrd_filename) {
> @@ -308,7 +348,8 @@ static void spike_board_init(MachineState *machine)
>                                fdt_load_addr);
>
>      /* initialize HTIF using symbols found in load_kernel */
> -    htif_mm_init(system_memory, serial_hd(0), memmap[SPIKE_HTIF].base);
> +    htif_mm_init(system_memory, serial_hd(0), memmap[SPIKE_HTIF].base,
> +                 htif_custom_base);
>  }
>
>  static void spike_machine_instance_init(Object *obj)
> --
> 2.34.1
>
>