From 018f4ef5f8b9c7fb3e0fa3574bfd2c17f24b4253 Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Sat, 12 Jun 2004 08:38:39 +0000 Subject: Jakub Bogusz from pld-linux dot org writes: Hello, I managed to get ldso (and thus shared linking to uClibc) to work on sparc (actually sparc64 kernel with 32-bit userspace), at least on simple "hello world" program (more complex ones not tested). Some notes on attached patch (against 0.9.26, would require some work to apply on current CVS - but I tested 0.9.26, not CVS): - ELF magic cannot be examined by _dl_strncmp so early, probably because of string constant, like on ppc/mips/sh (note that early SEND_STDERR still crashes when trying to do _dl_strlen - I suppose that string constants require relocation; but adding load_addr didn't help, just ELF header was displayed instead of crash) - mmap() is syscall6 like on ppc/mips/sh, not old i386 mmap() - for generic sparc (i.e. not sparcv8/sparcv9) gcc produces .udiv/.urem calls for unsigned integer / and % operators - so these operations must be avoided. I copied do_rem definition from arm header. But / and % are used also in _dl_simple_ltoa() and _dl_simple_ltoahex(); in ltoahex gcc optimizes it to shifts (but I think it's safer to use shifts explicitly, not rely on optimization...). I changed % in ltoa to do_rem, but as there was no do_div definition, I changed all "%d" specifiers to "%x" to avoid crashes (this changes wouldn't be needed if _dl_simple_ltoa() were fixed to not use division on sparc). - "#define SOLARIS_COMPATIBLE" in ld_sysdep.h broke ldso on Linux because of redefining _dl_linux_resolve only in some places (it was still referenced in INIT_GOT before redefinition). So _dl_linux_resolve redefinition should be moved before INIT_GOT definition or removed. - sparc64 kernel requires mmap() addresses to be aligned to 8192, not 4096, otherwise mmap() call failed - reloc_entry must be shifted by 10, not 12 (I found similar operation in glibc sources) Aside of sparc-specific fixes: - I moved some _dl_dprintf()s inside if(_dl_debug_*) conditions (to avoid debugging messages when LD_DEBUG is not defined) - it seems that there was possible off-by-one in ltoa and ltoahex? they are called with char[22] as 1st argument, and then '\0' is stored in local[22] (_before_ p decrementation)... or am I missing something? If not, fix is included in patch. --- ldso/include/dl-string.h | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'ldso/include/dl-string.h') diff --git a/ldso/include/dl-string.h b/ldso/include/dl-string.h index cbb867010..05f8d7d32 100644 --- a/ldso/include/dl-string.h +++ b/ldso/include/dl-string.h @@ -204,15 +204,18 @@ static inline char *_dl_get_last_path_component(char *path) } /* Early on, we can't call printf, so use this to print out - * numbers using the SEND_STDERR() macro */ + * numbers using the SEND_STDERR() macro. Avoid using mod + * or using long division */ static inline char *_dl_simple_ltoa(char * local, unsigned long i) { /* 21 digits plus null terminator, good for 64-bit or smaller ints */ - char *p = &local[22]; + char *p = &local[21]; *p-- = '\0'; do { - *p-- = '0' + i % 10; - i /= 10; + char temp; + do_rem(temp, i, 10); + *p-- = '0' + temp; + i /= 10; } while (i > 0); return p + 1; } @@ -220,15 +223,15 @@ static inline char *_dl_simple_ltoa(char * local, unsigned long i) static inline char *_dl_simple_ltoahex(char * local, unsigned long i) { /* 21 digits plus null terminator, good for 64-bit or smaller ints */ - char *p = &local[22]; + char *p = &local[21]; *p-- = '\0'; do { - char temp = i % 0x10; + char temp = i & 0xf; if (temp <= 0x09) *p-- = '0' + temp; else *p-- = 'a' - 0x0a + temp; - i /= 0x10; + i >>= 4; } while (i > 0); *p-- = 'x'; *p-- = '0'; -- cgit v1.2.3