Re: [Qemu-devel] [PATCH 2/6] mips_malta: correct reading MIPS revision at 0x1fc00010

["Andreas Färber" <afaerber@suse.de>]

Am 14.06.2013 09:30, schrieb Leon Alrae:
> From: Paul Burton <paul.burton@imgtec.com>
> 
> Rather than modifying the BIOS code at its original location, copy it
> for the 0x1fc00000 region & modify the copy. This means the original
> ROM code is correctly readable at 0x1e000010 whilst the MIPS revision
> is readable at 0x1fc00010.
> 
> Additionally the code previously operated on target memory which would
> later be overwritten by the BIOS image upon CPU reset if the -bios
> argument was used to specify the BIOS image. This led to the written
> MIPS revision being lost. Copying using rom_copy when -bios is used
> fixes this issue.
> 
> Signed-off-by: Paul Burton <paul.burton@imgtec.com>
> Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
> ---
>  hw/mips/mips_malta.c |   25 +++++++++++++++++--------
>  1 files changed, 17 insertions(+), 8 deletions(-)

For some reason this commit breaks `make check`, please revert or fix.

Andreas

> 
> diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
> index 4def898..9117ae4 100644
> --- a/hw/mips/mips_malta.c
> +++ b/hw/mips/mips_malta.c
> @@ -789,7 +789,7 @@ void mips_malta_init(QEMUMachineInitArgs *args)
>      pflash_t *fl;
>      MemoryRegion *system_memory = get_system_memory();
>      MemoryRegion *ram = g_new(MemoryRegion, 1);
> -    MemoryRegion *bios, *bios_alias = g_new(MemoryRegion, 1);
> +    MemoryRegion *bios, *bios_copy = g_new(MemoryRegion, 1);
>      target_long bios_size = FLASH_SIZE;
>      int64_t kernel_entry;
>      PCIBus *pci_bus;
> @@ -929,14 +929,23 @@ void mips_malta_init(QEMUMachineInitArgs *args)
>  #endif
>      }
>  
> -    /* Map the BIOS at a 2nd physical location, as on the real board. */
> -    memory_region_init_alias(bios_alias, "bios.1fc", bios, 0, BIOS_SIZE);
> -    memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_alias);
> +    /*
> +     * Map the BIOS at a 2nd physical location, as on the real board.
> +     * Copy it so that we can patch in the MIPS revision, which cannot be
> +     * handled by an overlapping region as the resulting ROM code subpage
> +     * regions are not executable.
> +     */
> +    memory_region_init_ram(bios_copy, "bios.1fc", BIOS_SIZE);
> +    if (!rom_copy(memory_region_get_ram_ptr(bios_copy),
> +                  FLASH_ADDRESS, bios_size)) {
> +        memcpy(memory_region_get_ram_ptr(bios_copy),
> +               memory_region_get_ram_ptr(bios), bios_size);
> +    }
> +    memory_region_set_readonly(bios_copy, true);
> +    memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_copy);
>  
> -    /* Board ID = 0x420 (Malta Board with CoreLV)
> -       XXX: theoretically 0x1e000010 should map to flash and 0x1fc00010 should
> -       map to the board ID. */
> -    stl_p(memory_region_get_ram_ptr(bios) + 0x10, 0x00000420);
> +    /* Board ID = 0x420 (Malta Board with CoreLV) */
> +    stl_p(memory_region_get_ram_ptr(bios_copy) + 0x10, 0x00000420);
>  
>      /* Init internal devices */
>      cpu_mips_irq_init_cpu(env);
> 


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