Re: [PATCH v6] x86_64: Correct THREAD_SETMEM/THREAD_SETMEM_NC for movq [BZ #27591]

[Carlos O'Donell <carlos@redhat.com>]

On 3/19/21 2:35 PM, H.J. Lu via Libc-alpha wrote:
> config/i386/constraints.md in GCC has
> 
> (define_constraint "e"
>   "32-bit signed integer constant, or a symbolic reference known
>    to fit that range (for immediate operands in sign-extending x86-64
>    instructions)."
>   (match_operand 0 "x86_64_immediate_operand"))
> 
> Since movq takes a signed 32-bit immediate or a register source operand,
> use "er", instead of "nr"/"ir", constraint for 32-bit signed integer
> constant or register on movq.

v6, and this version looks amazing, much better than before and I think
we've arrived a good solution to this problem. Thank you for your efforts
and working through the details.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> ---
>  sysdeps/x86_64/Makefile           |  2 +
>  sysdeps/x86_64/nptl/tls.h         | 10 ++++-
>  sysdeps/x86_64/tst-x86-64-tls-1.c | 64 +++++++++++++++++++++++++++++++
>  3 files changed, 74 insertions(+), 2 deletions(-)
>  create mode 100644 sysdeps/x86_64/tst-x86-64-tls-1.c
> 
> diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
> index d1d7cb9d2e..06a444b6af 100644
> --- a/sysdeps/x86_64/Makefile
> +++ b/sysdeps/x86_64/Makefile
> @@ -183,6 +183,8 @@ ifeq (no,$(build-hardcoded-path-in-tests))
>  tests-container += tst-glibc-hwcaps-cache
>  endif
>  
> +tests-internal += tst-x86-64-tls-1

OK. Test is internal with use of tls.h header.

> +
>  endif # $(subdir) == elf
>  
>  ifeq ($(subdir),csu)
> diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h
> index 20f0958780..a78c4f4d01 100644
> --- a/sysdeps/x86_64/nptl/tls.h
> +++ b/sysdeps/x86_64/nptl/tls.h
> @@ -271,8 +271,11 @@ _Static_assert (offsetof (tcbhead_t, __glibc_unused2) == 0x80,
>  		       "i" (offsetof (struct pthread, member)));	      \
>       else /* 8 */							      \
>         {								      \
> +	 /* Since movq takes a signed 32-bit immediate or a register source   \
> +	    operand, use "er" constraint for 32-bit signed integer constant   \
> +	    or register.  */						      \
>  	 asm volatile ("movq %q0,%%fs:%P1" :				      \
> -		       : IMM_MODE ((uint64_t) cast_to_integer (value)),	      \
> +		       : "er" ((uint64_t) cast_to_integer (value)),	      \

OK. Great change, very clear, and uses immediate or register to get it to work.

>  			 "i" (offsetof (struct pthread, member)));	      \
>         }})
>  
> @@ -296,8 +299,11 @@ _Static_assert (offsetof (tcbhead_t, __glibc_unused2) == 0x80,
>  		       "r" (idx));					      \
>       else /* 8 */							      \
>         {								      \
> +	 /* Since movq takes a signed 32-bit immediate or a register source   \
> +	    operand, use "er" constraint for 32-bit signed integer constant   \
> +	    or register.  */						      \
>  	 asm volatile ("movq %q0,%%fs:%P1(,%q2,8)" :			      \
> -		       : IMM_MODE ((uint64_t) cast_to_integer (value)),	      \
> +		       : "er" ((uint64_t) cast_to_integer (value)),	      \
>  			 "i" (offsetof (struct pthread, member[0])),	      \

OK.

>  			 "r" (idx));					      \
>         }})
> diff --git a/sysdeps/x86_64/tst-x86-64-tls-1.c b/sysdeps/x86_64/tst-x86-64-tls-1.c
> new file mode 100644
> index 0000000000..354635884e
> --- /dev/null
> +++ b/sysdeps/x86_64/tst-x86-64-tls-1.c
> @@ -0,0 +1,64 @@
> +/* Test THREAD_SETMEM and THREAD_SETMEM_NC for IMM64.
> +   Copyright (C) 2021 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <tls.h>
> +#include <support/check.h>
> +
> +static int
> +do_test (void)
> +{
> +  unsigned long long int saved_ssp_base, ssp_base;
> +  saved_ssp_base = THREAD_GETMEM (THREAD_SELF, header.ssp_base);
> +
> +  THREAD_SETMEM (THREAD_SELF, header.ssp_base, (1ULL << 57) - 1);
> +  ssp_base = THREAD_GETMEM (THREAD_SELF, header.ssp_base);
> +  if (ssp_base != ((1ULL << 57) - 1))
> +    FAIL_EXIT1 ("THREAD_SETMEM: 0x%llx != 0x%llx",
> +		ssp_base, (1ULL << 57) - 1);
> +
> +  THREAD_SETMEM (THREAD_SELF, header.ssp_base, -1ULL);
> +  ssp_base = THREAD_GETMEM (THREAD_SELF, header.ssp_base);
> +  if (ssp_base != -1ULL)
> +    FAIL_EXIT1 ("THREAD_SETMEM: 0x%llx != 0x%llx", ssp_base, -1ULL);
> +
> +  THREAD_SETMEM (THREAD_SELF, header.ssp_base, saved_ssp_base);
> +#ifndef __ILP32__
> +  struct pthread_key_data *saved_specific, *specific;
> +  saved_specific = THREAD_GETMEM_NC (THREAD_SELF, specific, 1);
> +
> +  uintptr_t value = (1UL << 57) - 1;
> +  THREAD_SETMEM_NC (THREAD_SELF, specific, 1,
> +		    (struct pthread_key_data *) value);
> +  specific = THREAD_GETMEM_NC (THREAD_SELF, specific, 1);
> +  if (specific != (struct pthread_key_data *) value)
> +    FAIL_EXIT1 ("THREAD_GETMEM_NC: %p != %p",
> +		specific, (struct pthread_key_data *) value);
> +
> +  THREAD_SETMEM_NC (THREAD_SELF, specific, 1,
> +		    (struct pthread_key_data *) -1UL);
> +  specific = THREAD_GETMEM_NC (THREAD_SELF, specific, 1);
> +  if (specific != (struct pthread_key_data *) -1UL)
> +    FAIL_EXIT1 ("THREAD_GETMEM_NC: %p != %p",
> +		specific, (struct pthread_key_data *) -1UL);
> +
> +  THREAD_SETMEM_NC (THREAD_SELF, specific, 1, saved_specific);
> +#endif
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>

OK.

> 


-- 
Cheers,
Carlos.