Re: [PATCH v1 40/43] hw/loongarch: Add LoongArch boot code and load elf function.

[Richard Henderson <richard.henderson@linaro.org>]

On 4/15/22 02:40, Xiaojuan Yang wrote:
> +static void ls3a5k_aui_boot(uint64_t start_addr)
> +{
> +    unsigned int ls3a5k_aui_boot_code[] = {
> +        0x18000064, /* pcaddi  $r4, 0x3    */
> +        0x28c00084, /* ld.d    $r4, $r4, 0 */
> +        0x4c000080, /* jirl    $r0, $r4, 0 */
> +        start_addr, /* elf pc address      */
> +    };
> +    int bios_size = sizeof(ls3a5k_aui_boot_code);
> +
> +    rom_add_blob_fixed("bios", ls3a5k_aui_boot_code, bios_size, LA_BIOS_BASE);

This only works on little endian hosts.  While you could fix this, it seems better to use 
a reset hook to cpu_set_pc() directly.  E.g. hw/arm/boot.c, do_cpu_reset.


> +    memory_region_init_ram(&lams->bios, NULL, "loongarch.bios",
> +                           LA_BIOS_SIZE, &error_fatal);
> +    memory_region_set_readonly(&lams->bios, true);

This is exactly memory_region_init_rom.

> +#define LA_BIOS_SIZE            (4 * 1024 * 1024)

qemu/units.h has MiB.


r~