[PATCH v6 0/1] RFC: Add <sys/tagged-address.h>

[H.J. Lu]

Changes in v6:

1. Update and simplify the API by only exporting:

/* Set the mask for address bits used in address translation.  Return 0
   on success.  Return -1 on error.  */
extern int set_translated_address_mask (uintptr_t __mask);

/* Non-zero if constant address BITS is a valid tagged address bits.  */
#define TRANSLATED_ADDRESS_VALID_BITS(BITS)

/* A mask for constant address BITS used in address translation.  */
#define TRANSLATED_ADDRESS_MASK(BITS)

2. Properly use _Static_assert for C and static_assert for C++.

Changes in v5:

Add restrictions:

1. All bits between 0 and N - 1, where N is the number of tagged address
bits, are used in address translation.
2. All pointers participating in a pointer arithmetic operation should have
the same tag if they point to the same memory object so that pointer
equality operation can be performed on tagged pointers.

Changes in v4:

1. Document that the zero return value from get_tagged_address_bits
indicates that tag bits are not the highest bits in address.
2. Document that the zero value of TAGGED_ADDRESS_MASK indicates the
invalid address mask.
3. Add <bits/tagged-address-mask.h> to provide TAGGED_ADDRESS_MASK.
4. Add C++ support to TAGGED_ADDRESS_MASK.

Changes in v3:

1. set_tagged_address_mask can be only called once before main.
2. Add more tests.

---
By default, the number of the address bits used in address translation
is the number of address bits.  But it can be changed by ARM Top-byte
Ignore (TBI) or Intel Linear Address Masking (LAM).

<sys/tagged-address.h> provides an API for tagged address manipulation.

H.J. Lu (1):
  <sys/tagged-address.h>: An API for tagged address

 NEWS                                          |  2 +-
 bits/tagged-address-mask.h                    | 47 ++++++++++++++++
 bits/tagged-address-valid-bits.h              | 28 ++++++++++
 csu/libc-start.c                              |  3 +
 elf/dl-support.c                              |  5 ++
 include/sys/tagged-address.h                  | 18 ++++++
 manual/Makefile                               |  3 +-
 manual/ctype.texi                             |  2 +-
 manual/memory.texi                            |  2 +-
 manual/tagged-address.texi                    | 48 ++++++++++++++++
 misc/Makefile                                 | 40 ++++++++++++--
 misc/Versions                                 | 10 ++++
 misc/set-translated-address-mask.c            | 41 ++++++++++++++
 misc/sys/tagged-address.h                     | 33 +++++++++++
 misc/tagged-address.c                         | 50 +++++++++++++++++
 misc/tst-tagged-address-1-static.c            |  1 +
 misc/tst-tagged-address-1.c                   | 55 +++++++++++++++++++
 misc/tst-tagged-address-2-static.c            |  1 +
 misc/tst-tagged-address-2.c                   | 45 +++++++++++++++
 misc/tst-tagged-address-3-static.c            |  1 +
 misc/tst-tagged-address-3.c                   | 48 ++++++++++++++++
 misc/tst-tagged-address-4-static.c            |  1 +
 misc/tst-tagged-address-4.c                   | 36 ++++++++++++
 misc/tst-tagged-address-5.c                   | 25 +++++++++
 misc/tst-tagged-address-6.c                   | 34 ++++++++++++
 misc/tst-tagged-address-7.c                   | 41 ++++++++++++++
 misc/tst-tagged-address-mod-5.c               | 47 ++++++++++++++++
 misc/tst-tagged-address-mod-6.c               | 34 ++++++++++++
 misc/tst-tagged-address-mod-7.c               | 35 ++++++++++++
 sysdeps/generic/inline-tagged-address.h       | 43 +++++++++++++++
 sysdeps/generic/ldsodefs.h                    |  4 ++
 sysdeps/unix/sysv/linux/i386/libc.abilist     |  1 +
 .../unix/sysv/linux/x86_64/64/libc.abilist    |  1 +
 .../unix/sysv/linux/x86_64/x32/libc.abilist   |  1 +
 34 files changed, 777 insertions(+), 9 deletions(-)
 create mode 100644 bits/tagged-address-mask.h
 create mode 100644 bits/tagged-address-valid-bits.h
 create mode 100644 include/sys/tagged-address.h
 create mode 100644 manual/tagged-address.texi
 create mode 100644 misc/set-translated-address-mask.c
 create mode 100644 misc/sys/tagged-address.h
 create mode 100644 misc/tagged-address.c
 create mode 100644 misc/tst-tagged-address-1-static.c
 create mode 100644 misc/tst-tagged-address-1.c
 create mode 100644 misc/tst-tagged-address-2-static.c
 create mode 100644 misc/tst-tagged-address-2.c
 create mode 100644 misc/tst-tagged-address-3-static.c
 create mode 100644 misc/tst-tagged-address-3.c
 create mode 100644 misc/tst-tagged-address-4-static.c
 create mode 100644 misc/tst-tagged-address-4.c
 create mode 100644 misc/tst-tagged-address-5.c
 create mode 100644 misc/tst-tagged-address-6.c
 create mode 100644 misc/tst-tagged-address-7.c
 create mode 100644 misc/tst-tagged-address-mod-5.c
 create mode 100644 misc/tst-tagged-address-mod-6.c
 create mode 100644 misc/tst-tagged-address-mod-7.c
 create mode 100644 sysdeps/generic/inline-tagged-address.h

-- 
2.31.1