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Date:	Thu, 10 Dec 2015 01:09:47 +0200
From:	Andy Shevchenko <andy.shevchenko@...il.com>
To:	Joe Perches <joe@...ches.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH] hexdump: Add ability to do endian conversions in
 print_hex_dump functions

On Thu, Dec 10, 2015 at 12:11 AM, Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
> On Wed, Dec 9, 2015 at 11:59 PM, Joe Perches <joe@...ches.com> wrote:
>> There are use cases for dumping buffers with specific endian types
>> for 2, 4, and 8 byte variables in arrays.
>>
>> Add an enum for DUMP_TYPE_(LE|BE|CPU) to enable emitting them as such.
>>
>> Rename groupsize to groupflags in the functions and add documentation
>> to the kernel-doc to describe the use of the DUMP_TYPE_ enum.
>
> One comment below and my tag
> Acked-by: Andy Shevchenko <andy.shevchenko@...il.com>

Couple of additional notes. (Tag still in power)

1. There is similar to print_hex_dump() function in seq_file. Separate patch?
2. What to do with ASCII part? Shall we print it as byte stream?

And one more style comment below.

>
>>
>> Signed-off-by: Joe Perches <joe@...ches.com>
>> ---
>>  include/linux/printk.h | 23 +++++++++++++++--------
>>  lib/hexdump.c          | 49 ++++++++++++++++++++++++++++++++++++++-----------
>>  2 files changed, 53 insertions(+), 19 deletions(-)
>>
>> diff --git a/include/linux/printk.h b/include/linux/printk.h
>
>> index 9729565..aac2943 100644
>> --- a/include/linux/printk.h
>> +++ b/include/linux/printk.h
>> @@ -424,12 +424,19 @@ enum {
>>         DUMP_PREFIX_ADDRESS,
>>         DUMP_PREFIX_OFFSET
>>  };
>> +
>> +enum {
>> +       DUMP_TYPE_CPU = 0,
>> +       DUMP_TYPE_LE = BIT(30),
>> +       DUMP_TYPE_BE = BIT(31)
>> +};
>> +
>>  extern int hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
>> -                             int groupsize, char *linebuf, size_t linebuflen,
>> +                             int groupflags, char *linebuf, size_t linebuflen,
>>                               bool ascii);
>>  #ifdef CONFIG_PRINTK
>>  extern void print_hex_dump(const char *level, const char *prefix_str,
>> -                          int prefix_type, int rowsize, int groupsize,
>> +                          int prefix_type, int rowsize, int groupflags,
>>                            const void *buf, size_t len, bool ascii);
>>  #if defined(CONFIG_DYNAMIC_DEBUG)
>>  #define print_hex_dump_bytes(prefix_str, prefix_type, buf, len)        \
>> @@ -440,7 +447,7 @@ extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
>>  #endif /* defined(CONFIG_DYNAMIC_DEBUG) */
>>  #else
>>  static inline void print_hex_dump(const char *level, const char *prefix_str,
>> -                                 int prefix_type, int rowsize, int groupsize,
>> +                                 int prefix_type, int rowsize, int groupflags,
>>                                   const void *buf, size_t len, bool ascii)
>>  {
>>  }
>> @@ -453,17 +460,17 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
>>
>>  #if defined(CONFIG_DYNAMIC_DEBUG)
>>  #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
>> -                            groupsize, buf, len, ascii)        \
>> +                            groupflags, buf, len, ascii)       \
>>         dynamic_hex_dump(prefix_str, prefix_type, rowsize,      \
>> -                        groupsize, buf, len, ascii)
>> +                        groupflags, buf, len, ascii)
>>  #elif defined(DEBUG)
>>  #define print_hex_dump_debug(prefix_str, prefix_type, rowsize,         \
>> -                            groupsize, buf, len, ascii)                \
>> +                            groupflags, buf, len, ascii)               \
>>         print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, rowsize,    \
>> -                      groupsize, buf, len, ascii)
>> +                      groupflags, buf, len, ascii)
>>  #else
>>  static inline void print_hex_dump_debug(const char *prefix_str, int prefix_type,
>> -                                       int rowsize, int groupsize,
>> +                                       int rowsize, int groupflags,
>>                                         const void *buf, size_t len, bool ascii)
>>  {
>>  }
>> diff --git a/lib/hexdump.c b/lib/hexdump.c
>> index 992457b..f44608e 100644
>> --- a/lib/hexdump.c
>> +++ b/lib/hexdump.c
>> @@ -80,7 +80,9 @@ EXPORT_SYMBOL(bin2hex);
>>   * @buf: data blob to dump
>>   * @len: number of bytes in the @buf
>>   * @rowsize: number of bytes to print per line; must be 16 or 32
>> - * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
>> + * @groupflags: number of bytes to print at a time (1, 2, 4, 8; default = 1)
>> + *  use a bitwise OR with %DUMP_TYPE_BE or %DUMP_TYPE_LE for endian conversions
>> + *  of @buf, otherwise %DUMP_TYPE_CPU is used
>>   * @linebuf: where to put the converted data
>>   * @linebuflen: total size of @linebuf, including space for terminating NUL
>>   * @ascii: include ASCII after the hex output
>> @@ -105,7 +107,7 @@ EXPORT_SYMBOL(bin2hex);
>>   * (excluding the terminating NUL) which would have been written to the final
>>   * string if enough space had been available.
>>   */
>> -int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
>> +int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupflags,
>>                        char *linebuf, size_t linebuflen, bool ascii)
>>  {
>>         const u8 *ptr = buf;
>> @@ -114,6 +116,7 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
>>         int j, lx = 0;
>>         int ascii_column;
>>         int ret;
>> +       int groupsize = groupflags & ~(DUMP_TYPE_LE | DUMP_TYPE_BE);

Can you move this upper to first or second position in the definition block?

>>
>>         if (rowsize != 16 && rowsize != 32)
>>                 rowsize = 16;
>> @@ -138,9 +141,16 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
>>                 const u64 *ptr8 = buf;
>>
>>                 for (j = 0; j < ngroups; j++) {
>> +                       u64 val;
>> +
>> +                       if (groupflags & DUMP_TYPE_LE)
>> +                               val = get_unaligned_le64(ptr8 + j);
>> +                       else if (groupflags & DUMP_TYPE_BE)
>> +                               val = get_unaligned_be64(ptr8 + j);
>> +                       else
>> +                               val = get_unaligned(ptr8 + j);
>>                         ret = snprintf(linebuf + lx, linebuflen - lx,
>> -                                      "%s%16.16llx", j ? " " : "",
>> -                                      get_unaligned(ptr8 + j));
>> +                                      "%s%16.16llx", j ? " " : "", val);
>>                         if (ret >= linebuflen - lx)
>>                                 goto overflow1;
>>                         lx += ret;
>> @@ -149,9 +159,16 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
>>                 const u32 *ptr4 = buf;
>>
>>                 for (j = 0; j < ngroups; j++) {
>> +                       u32 val;
>> +
>> +                       if (groupflags & DUMP_TYPE_LE)
>> +                               val = get_unaligned_le32(ptr4 + j);
>> +                       else if (groupflags & DUMP_TYPE_BE)
>> +                               val = get_unaligned_be32(ptr4 + j);
>> +                       else
>> +                               val = get_unaligned(ptr4 + j);
>>                         ret = snprintf(linebuf + lx, linebuflen - lx,
>> -                                      "%s%8.8x", j ? " " : "",
>> -                                      get_unaligned(ptr4 + j));
>> +                                      "%s%8.8x", j ? " " : "", val);
>>                         if (ret >= linebuflen - lx)
>>                                 goto overflow1;
>>                         lx += ret;
>> @@ -160,9 +177,16 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
>>                 const u16 *ptr2 = buf;
>>
>>                 for (j = 0; j < ngroups; j++) {
>> +                       u16 val;
>> +
>> +                       if (groupflags & DUMP_TYPE_LE)
>> +                               val = get_unaligned_le16(ptr2 + j);
>> +                       else if (groupflags & DUMP_TYPE_BE)
>> +                               val = get_unaligned_be16(ptr2 + j);
>> +                       else
>> +                               val = get_unaligned(ptr2 + j);
>>                         ret = snprintf(linebuf + lx, linebuflen - lx,
>> -                                      "%s%4.4x", j ? " " : "",
>> -                                      get_unaligned(ptr2 + j));
>> +                                      "%s%4.4x", j ? " " : "", val);
>>                         if (ret >= linebuflen - lx)
>>                                 goto overflow1;
>>                         lx += ret;
>> @@ -216,7 +240,10 @@ EXPORT_SYMBOL(hex_dump_to_buffer);
>>   * @prefix_type: controls whether prefix of an offset, address, or none
>>   *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
>>   * @rowsize: number of bytes to print per line; must be 16 or 32
>> - * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
>> + * @groupflags: number of bytes to print at a time (1, 2, 4, 8; default = 1)
>
>> + * @groupflags: number of bytes to print at a time (1, 2, 4, 8; default = 1)
>
> Duplicate.
>
>> + *  use a bitwise OR with %DUMP_TYPE_BE or %DUMP_TYPE_LE for endian conversions
>> + *  of @buf, otherwise %DUMP_TYPE_CPU is used
>>   * @buf: data blob to dump
>>   * @len: number of bytes in the @buf
>>   * @ascii: include ASCII after the hex output
>> @@ -240,7 +267,7 @@ EXPORT_SYMBOL(hex_dump_to_buffer);
>>   * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
>>   */
>>  void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
>> -                   int rowsize, int groupsize,
>> +                   int rowsize, int groupflags,
>>                     const void *buf, size_t len, bool ascii)
>>  {
>>         const u8 *ptr = buf;
>> @@ -254,7 +281,7 @@ void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
>>                 linelen = min(remaining, rowsize);
>>                 remaining -= rowsize;
>>
>> -               hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
>> +               hex_dump_to_buffer(ptr + i, linelen, rowsize, groupflags,
>>                                    linebuf, sizeof(linebuf), ascii);
>>
>>                 switch (prefix_type) {
>> --
>> 2.6.3.368.gf34be46
>>
>
>
>
> --
> With Best Regards,
> Andy Shevchenko



-- 
With Best Regards,
Andy Shevchenko
--
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