Fwd: [RFC 3/5] MIPS: add ELF support

[Antony Pavlov <antonynpavlov@gmail.com>]

On 21 December 2012 11:53, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Thu, Dec 20, 2012 at 01:29:53AM +0400, Antony Pavlov wrote:
>> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
>> ---
>>  arch/mips/Kconfig               |    1 +
>>  arch/mips/include/asm/elf.h     |    8 ++-
>>  arch/mips/include/asm/io.h      |   18 ++++++
>>  arch/mips/lib/Makefile          |    3 +
>>  arch/mips/lib/kexec-elf-mips.c  |   83 +++++++++++++++++++++++++
>>  arch/mips/lib/kexec-mips.c      |  130 +++++++++++++++++++++++++++++++++++++++
>>  arch/mips/lib/kexec-mips.h      |   24 ++++++++
>>  arch/mips/lib/relocate_kernel.S |   77 +++++++++++++++++++++++
>>  8 files changed, 343 insertions(+), 1 deletion(-)
>>  create mode 100644 arch/mips/lib/kexec-elf-mips.c
>>  create mode 100644 arch/mips/lib/kexec-mips.c
>>  create mode 100644 arch/mips/lib/kexec-mips.h
>>  create mode 100644 arch/mips/lib/relocate_kernel.S
>>
>> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
>> index 947edcf..3a7f775 100644
>> --- a/arch/mips/Kconfig
>> +++ b/arch/mips/Kconfig
>> @@ -6,6 +6,7 @@ config MIPS
>>       select HAS_KALLSYMS
>>       select HAVE_CONFIGURABLE_MEMORY_LAYOUT
>>       select HAVE_CONFIGURABLE_TEXT_BASE
>> +     select HAS_KEXEC
>>       default y
>>
>>  config SYS_SUPPORTS_BIG_ENDIAN
>> diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
>> index b8b8219..bf974f5 100644
>> --- a/arch/mips/include/asm/elf.h
>> +++ b/arch/mips/include/asm/elf.h
>> @@ -17,12 +17,18 @@
>>
>>  #ifndef ELF_ARCH
>>
>> +/* Legal values for e_machine (architecture).  */
>> +
>> +#define EM_MIPS               8              /* MIPS R3000 big-endian */
>> +#define EM_MIPS_RS4_BE       10              /* MIPS R4000 big-endian */
>> +
>>  #ifdef CONFIG_32BIT
>>
>>  /*
>>   * This is used to ensure we don't load something for the wrong architecture.
>>   */
>> -#define elf_check_arch(hdr)                                          \
>> +#define elf_check_arch(x) ((x)->e_machine == EM_MIPS)
>> +
>>  /*
>>   * These are used to set parameters in the core dumps.
>>   */
>> diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
>> index 4100e1e..f22ef6f 100644
>> --- a/arch/mips/include/asm/io.h
>> +++ b/arch/mips/include/asm/io.h
>> @@ -14,6 +14,24 @@
>>  #include <asm/types.h>
>>  #include <asm/byteorder.h>
>>
>> +/*
>> + *     virt_to_phys    -       map virtual addresses to physical
>> + *     @address: address to remap
>> + *
>> + *     The returned physical address is the physical (CPU) mapping for
>> + *     the memory address given. It is only valid to use this function on
>> + *     addresses directly mapped or allocated via kmalloc.
>> + *
>> + *     This function does not give bus mappings for DMA transfers. In
>> + *     almost all conceivable cases a device driver should not be using
>> + *     this function
>> + */
>> +static inline unsigned long virt_to_phys(volatile const void *address)
>> +{
>> +     //return (unsigned long)address - PAGE_OFFSET + PHYS_OFFSET;
>> +     return (unsigned long)address & 0x1fffffff;
>
> Why this? I would assume that you have a 1:1 mapping on Mips?

No.
On MIPS virtual address, used by programmer just always differ from
physical address.
Just now mips barebox work in KSEG1 (uncached) memory region
(0xa0000000 --- 0xc0000000), after cache support adding mips barebox
will work in KSEG0 (cached) memory region (0x80000000 --- 0xa0000000).
Both memory regions (KSEG1 and KSEG0) map to the same physical
addresses (0x00000000 --- 0x20000000).


>> +
>> +#define _GNU_SOURCE
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <stdlib.h>
>> +#include <errno.h>
>> +#include <asm/io.h>
>> +#include <linux/types.h>
>> +#include <fcntl.h>
>> +#include <elf.h>
>> +#include "../../../lib/kexec/kexec.h"
>> +#include "../../../lib/kexec/kexec-elf.h"
>
> So the they should be better in include/kexec/

ok

> Sascha
>
> --
> Pengutronix e.K.                           |                             |
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--
Best regards,
  Antony Pavlov

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