[Bug dynamic-link/21908] dynamic linker broke on ia64 (mmap2 consolidation is the suspect)

["slyfox at inbox dot ru" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=21908

--- Comment #10 from Sergei Trofimovich <slyfox at inbox dot ru> ---
(In reply to Adhemerval Zanella from comment #6)
> In fact the part of default part MMAP_OFF_HIGH_MASK is unnecessary, the
> patch could be simplified: 
> 
> diff --git a/sysdeps/unix/sysv/linux/m68k/mmap_internal.h
> b/sysdeps/unix/sysv/linux/m68k/mmap_internal.h
> index bd8bd38..9fe9d91 100644
> --- a/sysdeps/unix/sysv/linux/m68k/mmap_internal.h
> +++ b/sysdeps/unix/sysv/linux/m68k/mmap_internal.h
> @@ -22,7 +22,7 @@
>  /* ColdFire and Sun 3 kernels have PAGE_SHIFT set to 13 and expect
>     mmap2 offset to be provided in 8K pages.  Determine the shift
>     dynamically with getpagesize.  */
> -#define MMAP2_PAGE_SHIFT -1
> +#define MMAP2_PAGE_UNIT -1
> 
>  #include_next <mmap_internal.h>
> 
> diff --git a/sysdeps/unix/sysv/linux/mmap_internal.h
> b/sysdeps/unix/sysv/linux/mmap_internal.h
> index 499e389..47c0991 100644
> --- a/sysdeps/unix/sysv/linux/mmap_internal.h
> +++ b/sysdeps/unix/sysv/linux/mmap_internal.h
> @@ -27,13 +27,13 @@
>  #endif
> 
>  #if MMAP2_PAGE_UNIT == -1
> -static int page_unit;
> -
> +static uint64_t page_unit;
>  # define MMAP_CHECK_PAGE_UNIT()                        \
>    if (page_unit == 0)                          \
>      page_unit = __getpagesize ();
> +# undef MMAP2_PAGE_UNIT
> +# define MMAP2_PAGE_UNIT page_unit
>  #else
> -# define page_unit MMAP2_PAGE_UNIT
>  # define MMAP_CHECK_PAGE_UNIT()
>  #endif

Looks good! For ia64 I've also created the following file locally:

--- /dev/null
+++ b/sysdeps/unix/sysv/linux/ia64/mmap_internal.h
@@ -0,0 +1,11 @@
+#ifndef MMAP_IA64_INTERNAL_LINUX_H
+#define MMAP_IA64_INTERNAL_LINUX_H
+
+/* Linux kernel allows PAGE_SHIFT in range of [12-16] and expect
+   mmap2 offset to be provided in 8K pages. Determine the shift
+   dynamically with getpagesize. See sourceware.org/PR21908.  */
+#define MMAP2_PAGE_UNIT -1
+
+#include_next <mmap_internal.h>
+
+#endif

It almost compiles:

gcc ../sysdeps/unix/sysv/linux/mmap.c -c -std=gnu11 -fgnu89-inline  -O2 -Wall
-Werror -Wundef -Wwrite-strings -fmerge-all-constants -fno-stack-protector
-frounding-math -g -Wstrict-prototypes -Wold-style-definition    
-ftls-model=initial-exec   -U_FORTIFY_SOURCE   -I../include
-I/root/glibc-build/misc  -I/root/glibc-build 
-I../sysdeps/unix/sysv/linux/ia64  -I../sysdeps/ia64/nptl 
-I../sysdeps/unix/sysv/linux/wordsize-64  -I../sysdeps/unix/sysv/linux/include
-I../sysdeps/unix/sysv/linux  -I../sysdeps/nptl  -I../sysdeps/pthread 
-I../sysdeps/gnu  -I../sysdeps/unix/inet  -I../sysdeps/unix/sysv 
-I../sysdeps/unix  -I../sysdeps/posix  -I../sysdeps/ia64/fpu  -I../sysdeps/ia64
 -I../sysdeps/wordsize-64  -I../sysdeps/ieee754/float128 
-I../sysdeps/ieee754/ldbl-96/include -I../sysdeps/ieee754/ldbl-96 
-I../sysdeps/ieee754/dbl-64  -I../sysdeps/ieee754/flt-32  -I../sysdeps/ieee754 
-I../sysdeps/generic  -I.. -I../libio -I.   -D_LIBC_REENTRANT -include
/root/glibc-build/libc-modules.h -DMODULE_NAME=libc -include
../include/libc-symbols.h       -DTOP_NAMESPACE=glibc -o
/root/glibc-build/misc/mmap.o -MD -MP -MF /root/glibc-build/misc/mmap.o.dt -MT
/root/glibc-build/misc/mmap.o
In file included from ../sysdeps/unix/sysv/linux/ia64/mmap_internal.h:9:0,
                 from ../sysdeps/unix/sysv/linux/mmap.c:24:
../sysdeps/unix/sysv/linux/mmap_internal.h:30:17: error: 'page_unit' defined
but not used [-Werror=unused-variable]
 static uint64_t page_unit;
                 ^~~~~~~~~

That file does not generate any code for non-__OFF_T_MATCHES_OFF64_T case.
Worked around as:

--- a/sysdeps/unix/sysv/linux/mmap.c
+++ b/sysdeps/unix/sysv/linux/mmap.c
@@ -23,5 +23,5 @@
 #include <stdint.h>
-#include <mmap_internal.h>

 #ifndef __OFF_T_MATCHES_OFF64_T
+#include <mmap_internal.h>

With those rtld works on ia64!

(In reply to Andreas Schwab from comment #8)
> You cannot change the syscall any more, this is now history.

Worth adding mmap3?

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