linux-kernel - Re: [PATCH v4 2/5] ia64: reuse append_elf_note() and final

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Message-Id: <0748026f-a459-9022-3658-a75cb0633f40@linux.vnet.ibm.com>
Date:   Tue, 24 Jan 2017 23:41:59 +0530
From:   Hari Bathini <hbathini@...ux.vnet.ibm.com>
To:     fenghua.yu@...el.com, tony.luck@...el.com,
        linux-ia64@...r.kernel.org
Cc:     Dave Young <dyoung@...hat.com>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, ebiederm@...ssion.com,
        Michael Ellerman <mpe@...erman.id.au>,
        linuxppc-dev@...ts.ozlabs.org, vgoyal@...hat.com
Subject: Re: [PATCH v4 2/5] ia64: reuse append_elf_note() and final_note()
 functions



On Tuesday 17 January 2017 10:36 PM, Hari Bathini wrote:
>
>
> On Friday 06 January 2017 07:33 AM, Dave Young wrote:
>> On 01/05/17 at 11:01pm, Hari Bathini wrote:
>>> Get rid of multiple definitions of append_elf_note() & final_note()
>>> functions. Reuse these functions compiled under CONFIG_CRASH_CORE
>>> Also, define Elf_Word and use it instead of generic u32 or the more
>>> specific Elf64_Word.
>>>
>>> Signed-off-by: Hari Bathini <hbathini@...ux.vnet.ibm.com>
>>> ---
>>>
>>> Changes from v3:
>>> * Dropped hard-coded values and used DIV_ROUND_UP().
>>>
>>> Changes from v2:
>>> * Added a definition for Elf_Word.
>>> * Used IA64 version of append_elf_note() and final_note() functions.
>>>
>>>
>>>   arch/ia64/kernel/crash.c   |   22 ----------------------
>>>   include/linux/crash_core.h |    4 ++++
>>>   include/linux/elf.h        |    2 ++
>>>   kernel/crash_core.c        |   34 ++++++++++++++--------------------
>>>   kernel/kexec_core.c        |   28 ----------------------------
>>>   5 files changed, 20 insertions(+), 70 deletions(-)
>>>
>>> diff --git a/arch/ia64/kernel/crash.c b/arch/ia64/kernel/crash.c
>>> index 2955f35..75859a0 100644
>>> --- a/arch/ia64/kernel/crash.c
>>> +++ b/arch/ia64/kernel/crash.c
>>> @@ -27,28 +27,6 @@ static int kdump_freeze_monarch;
>>>   static int kdump_on_init = 1;
>>>   static int kdump_on_fatal_mca = 1;
>>>   -static inline Elf64_Word
>>> -*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void 
>>> *data,
>>> -        size_t data_len)
>>> -{
>>> -    struct elf_note *note = (struct elf_note *)buf;
>>> -    note->n_namesz = strlen(name) + 1;
>>> -    note->n_descsz = data_len;
>>> -    note->n_type   = type;
>>> -    buf += (sizeof(*note) + 3)/4;
>>> -    memcpy(buf, name, note->n_namesz);
>>> -    buf += (note->n_namesz + 3)/4;
>>> -    memcpy(buf, data, data_len);
>>> -    buf += (data_len + 3)/4;
>>> -    return buf;
>>> -}
>>> -
>>> -static void
>>> -final_note(void *buf)
>>> -{
>>> -    memset(buf, 0, sizeof(struct elf_note));
>>> -}
>>> -
>>>   extern void ia64_dump_cpu_regs(void *);
>>>     static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
>>> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
>>> index 18d0f94..541a197 100644
>>> --- a/include/linux/crash_core.h
>>> +++ b/include/linux/crash_core.h
>>> @@ -55,6 +55,10 @@ extern u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
>>>   extern size_t vmcoreinfo_size;
>>>   extern size_t vmcoreinfo_max_size;
>>>   +Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int 
>>> type,
>>> +              void *data, size_t data_len);
>>> +void final_note(Elf_Word *buf);
>>> +
>>>   int __init parse_crashkernel(char *cmdline, unsigned long long 
>>> system_ram,
>>>           unsigned long long *crash_size, unsigned long long 
>>> *crash_base);
>>>   int parse_crashkernel_high(char *cmdline, unsigned long long 
>>> system_ram,
>>> diff --git a/include/linux/elf.h b/include/linux/elf.h
>>> index 20fa8d8..ba069e8 100644
>>> --- a/include/linux/elf.h
>>> +++ b/include/linux/elf.h
>>> @@ -29,6 +29,7 @@ extern Elf32_Dyn _DYNAMIC [];
>>>   #define elf_note    elf32_note
>>>   #define elf_addr_t    Elf32_Off
>>>   #define Elf_Half    Elf32_Half
>>> +#define Elf_Word    Elf32_Word
>>>     #else
>>>   @@ -39,6 +40,7 @@ extern Elf64_Dyn _DYNAMIC [];
>>>   #define elf_note    elf64_note
>>>   #define elf_addr_t    Elf64_Off
>>>   #define Elf_Half    Elf64_Half
>>> +#define Elf_Word    Elf64_Word
>>>     #endif
>>>   diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>> index 80b441d..362dace 100644
>>> --- a/kernel/crash_core.c
>>> +++ b/kernel/crash_core.c
>>> @@ -291,32 +291,26 @@ int __init parse_crashkernel_low(char *cmdline,
>>>                   "crashkernel=", suffix_tbl[SUFFIX_LOW]);
>>>   }
>>>   -static u32 *append_elf_note(u32 *buf, char *name, unsigned int type,
>>> -                void *data, size_t data_len)
>>> +Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int 
>>> type,
>>> +              void *data, size_t data_len)
>>>   {
>>> -    struct elf_note note;
>>> -
>>> -    note.n_namesz = strlen(name) + 1;
>>> -    note.n_descsz = data_len;
>>> -    note.n_type   = type;
>>> -    memcpy(buf, &note, sizeof(note));
>>> -    buf += (sizeof(note) + 3)/4;
>>> -    memcpy(buf, name, note.n_namesz);
>>> -    buf += (note.n_namesz + 3)/4;
>>> -    memcpy(buf, data, note.n_descsz);
>>> -    buf += (note.n_descsz + 3)/4;
>>> +    struct elf_note *note = (struct elf_note *)buf;
>>> +
>>> +    note->n_namesz = strlen(name) + 1;
>>> +    note->n_descsz = data_len;
>>> +    note->n_type   = type;
>>> +    buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
>>> +    memcpy(buf, name, note->n_namesz);
>>> +    buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
>>> +    memcpy(buf, data, data_len);
>>> +    buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
>>>         return buf;
>>>   }
>>>   -static void final_note(u32 *buf)
>>> +void final_note(Elf_Word *buf)
>>>   {
>>> -    struct elf_note note;
>>> -
>>> -    note.n_namesz = 0;
>>> -    note.n_descsz = 0;
>>> -    note.n_type   = 0;
>>> -    memcpy(buf, &note, sizeof(note));
>>> +    memset(buf, 0, sizeof(struct elf_note));
>>>   }
>>>     static void update_vmcoreinfo_note(void)
>>> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
>>> index 2179a16..263d764 100644
>>> --- a/kernel/kexec_core.c
>>> +++ b/kernel/kexec_core.c
>>> @@ -990,34 +990,6 @@ int crash_shrink_memory(unsigned long new_size)
>>>       return ret;
>>>   }
>>>   -static u32 *append_elf_note(u32 *buf, char *name, unsigned type, 
>>> void *data,
>>> -                size_t data_len)
>>> -{
>>> -    struct elf_note note;
>>> -
>>> -    note.n_namesz = strlen(name) + 1;
>>> -    note.n_descsz = data_len;
>>> -    note.n_type   = type;
>>> -    memcpy(buf, &note, sizeof(note));
>>> -    buf += (sizeof(note) + 3)/4;
>>> -    memcpy(buf, name, note.n_namesz);
>>> -    buf += (note.n_namesz + 3)/4;
>>> -    memcpy(buf, data, note.n_descsz);
>>> -    buf += (note.n_descsz + 3)/4;
>>> -
>>> -    return buf;
>>> -}
>>> -
>>> -static void final_note(u32 *buf)
>>> -{
>>> -    struct elf_note note;
>>> -
>>> -    note.n_namesz = 0;
>>> -    note.n_descsz = 0;
>>> -    note.n_type   = 0;
>>> -    memcpy(buf, &note, sizeof(note));
>>> -}
>>> -
>>>   void crash_save_cpu(struct pt_regs *regs, int cpu)
>>>   {
>>>       struct elf_prstatus prstatus;
>>>
>> It looks good to me. But better to have words from IA64 people as well.
>>
>>
>
> Can someone from IA64 arch review this please?
>

Hello IA64 folks,

Could you please review this patch..?

Thanks
Hari