Messages in this thread Patch in this message | | | Date | Sun, 6 Apr 2003 01:02:11 +0200 | From | "J.A. Magallon" <> | Subject | [PATCH] AT_PLATFORM on HT-P4 |
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On 04.06, J.A. Magallon wrote: > > On 04.04, Marcelo Tosatti wrote: > > > > So here goes -pre7. Hopefully the last -pre. > > >
This makes P4 Xeon to report correct i686 platform. Without this, all those people that think its ld.so automatically picks i686 libs are wrong...
The original code takes u_platform for coyping ELF_PLATFORM, but also supposes it is the top of stack. This changes when we have siblings:
if(smp_num_siblings > 1) u_platform = u_platform - ((current->pid % 64) << 7);
Later:
NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
that on HT cpus is broken, isn't it ?
This separates the two things, stack top and u_platform. It could be even cleaner, with something like
stack_top = p; if (k_platform) sz = strlen(k_platform)+1 u_platform = stack_top - sz __copy_to_user(...) stack_top -= sz else u_platform = NULL ... if(smp_num_siblings > 1) stack_top = stack_top - ((current->pid % 64) << 7); ... if (u_platform) NEW_AUX_ENT(...)
But I have not tested it. Current patch below.
--- linux/fs/binfmt_elf.c.orig 2002-12-28 00:12:32.000000000 +0100 +++ linux/fs/binfmt_elf.c 2002-12-28 00:32:37.000000000 +0100 @@ -116,11 +116,14 @@ elf_caddr_t *argv; elf_caddr_t *envp; elf_addr_t *sp, *csp; + char *stack_top; char *k_platform, *u_platform; long hwcap; size_t platform_len = 0; size_t len; + stack_top = p; + /* * Get hold of platform and hardware capabilities masks for * the machine we are running on. In some cases (Sparc), @@ -135,8 +138,8 @@ platform_len = strlen(k_platform) + 1; u_platform = p - platform_len; __copy_to_user(u_platform, k_platform, platform_len); - } else - u_platform = p; + stack_top = u_platform; + } #if defined(__i386__) && defined(CONFIG_SMP) /* @@ -149,15 +152,14 @@ * processors. This keeps Mr Marcelo Person happier but should be * removed for 2.5 */ - if(smp_num_siblings > 1) - u_platform = u_platform - ((current->pid % 64) << 7); + stack_top -= ((current->pid % NR_CPUS) << 7); #endif /* * Force 16 byte _final_ alignment here for generality. */ - sp = (elf_addr_t *)(~15UL & (unsigned long)(u_platform)); + sp = (elf_addr_t *)(~15UL & (unsigned long)(stack_top)); csp = sp; csp -= (1+DLINFO_ITEMS)*2 + (k_platform ? 2 : 0); #ifdef DLINFO_ARCH_ITEMS
-- J.A. Magallon <jamagallon@able.es> \ Software is like sex: werewolf.able.es \ It's better when it's free Mandrake Linux release 9.2 (Bamboo) for i586 Linux 2.4.21-pre7-jam1 (gcc 3.2.2 (Mandrake Linux 9.2 3.2.2-5mdk)) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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