Re: [PATCH v4 2/5] ia64: reuse append_elf_note() and final_note() functions

[Hari Bathini <hbathini@linux.vnet.ibm.com>]

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@linux.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?

Thanks
Hari