- Use runtime pagesize (Jeremy Kerr)

Some powerpc machines can support 64k pages, enabled by the
CONFIG_64K_PAGES option in linux.

However, the uClibc dynamic loader won't currently work on these
machines, as it uses hard-coded values (PAGE_ALIGN, ADDR_ALIGN and
OFFS_ALIGN) in the ldso architecture-specific headers.  When running on
a kernel with 64k pages, ld.so tries to mmap with 4k-aligned addresses,
rather than 64k, so mmap fails with -EINVAL.

When booting a 64k machine with a uClibc dynamic linker, init fails
with:

/init:500: can't map '/lib/libc.so.0'
/init:500: can't map '/lib/libc.so.0'
/init:500: can't map '/lib/libc.so.0'
/init: can't load library 'libc.so.0'
Kernel panic - not syncing: Attempted to kill init!

This change allows ld.so determine these alignment masks at runtime,
rather than compile-time. Since we have the _dl_pagesize variable
available, we can use that to generate the appropriate masks.

Since almost all of the architectures can use the common definitions for
the _ALIGN macros, we can consolidate them all in ldso.h, and override
in the sysdep headers where necessary (ie, mips).

This allows me to start a uClibc-based root fs on a 64k machine.

Signed-off-by: Jeremy Kerr <jk at ozlabs org>

1 files changed, 0 insertions, 5 deletions

diff --git a/ldso/ldso/powerpc/dl-sysdep.h b/ldso/ldso/powerpc/dl-sysdep.h
index 768482272..fdbf564a7 100644
--- a/ldso/ldso/powerpc/dl-sysdep.h
+++ b/ldso/ldso/powerpc/dl-sysdep.h
@@ -67,11 +67,6 @@ struct elf_resolve;
 extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
 void _dl_init_got(unsigned long *lpnt,struct elf_resolve *tpnt);
 
-/* 4096 bytes alignment */
-#define PAGE_ALIGN 0xfffff000
-#define ADDR_ALIGN 0xfff
-#define OFFS_ALIGN 0x7ffff000
-
 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
    PLT entries should not be allowed to define the value.
    ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one