Skip to content

GitLab

Switch branch/tag
  1. 17 May, 2018 22 commits
  3. 27 Apr, 2018 2 commits
    • Masahiro Yamada's avatar
      types: use int-ll64 for both aarch32 and aarch64 · 0a2d5b43
      Masahiro Yamada authored 
      Since commit 031dbb12

 ("AArch32: Add essential Arch helpers"),
it is difficult to use consistent format strings for printf() family
between aarch32 and aarch64.

For example, uint64_t is defined as 'unsigned long long' for aarch32
and as 'unsigned long' for aarch64.  Likewise, uintptr_t is defined
as 'unsigned int' for aarch32, and as 'unsigned long' for aarch64.

A problem typically arises when you use printf() in common code.

One solution could be, to cast the arguments to a type long enough
for both architectures.  For example, if 'val' is uint64_t type,
like this:

  printf("val = %llx\n", (unsigned long long)val);

Or, somebody may suggest to use a macro provided by <inttypes.h>,
like this:

  printf("val = %" PRIx64 "\n", val);

But, both would make the code ugly.

The solution adopted in Linux kernel is to use the same typedefs for
all architectures.  The fixed integer types in the kernel-space have
been unified into int-ll64, like follows:

    typedef signed char           int8_t;
    typedef unsigned char         uint8_t;

    typedef signed short          int16_t;
    typedef unsigned short        uint16_t;

    typedef signed int            int32_t;
    typedef unsigned int          uint32_t;

    typedef signed long long      int64_t;
    typedef unsigned long long    uint64_t;

[ Linux commit: 0c79a8e29b5fcbcbfd611daf9d500cfad8370fcf ]

This gets along with the codebase shared between 32 bit and 64 bit,
with the data model called ILP32, LP64, respectively.

The width for primitive types is defined as follows:

                   ILP32           LP64
    int            32              32
    long           32              64
    long long      64              64
    pointer        32              64

'long long' is 64 bit for both, so it is used for defining uint64_t.
'long' has the same width as pointer, so for uintptr_t.

We still need an ifdef conditional for (s)size_t.

All 64 bit architectures use "unsigned long" size_t, and most 32 bit
architectures use "unsigned int" size_t.  H8/300, S/390 are known as
exceptions; they use "unsigned long" size_t despite their architecture
is 32 bit.

One idea for simplification might be to define size_t as 'unsigned long'
across architectures, then forbid the use of "%z" string format.
However, this would cause a distortion between size_t and sizeof()
operator.  We have unknowledge about the native type of sizeof(), so
we need a guess of it anyway.  I want the following formula to always
return 1:

  __builtin_types_compatible_p(size_t, typeof(sizeof(int)))

Fortunately, ARM is probably a majority case.  As far as I know, all
32 bit ARM compilers use "unsigned int" size_t.
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      0a2d5b43
    • Masahiro Yamada's avatar
      Fix pointer type mismatch of handlers · 57d1e5fa
      Masahiro Yamada authored 
      Commit 4c0d0390

 ("Rework type usage in Trusted Firmware") changed
the type usage in struct declarations, but did not touch the definition
side.  Fix the type mismatch.
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      57d1e5fa
  5. 26 Mar, 2018 1 commit
  7. 15 Mar, 2018 15 commits