From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752759AbaKDIu2 (ORCPT ); Tue, 4 Nov 2014 03:50:28 -0500 Received: from mail.emea.novell.com ([130.57.118.101]:58379 "EHLO mail.emea.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752756AbaKDIuX convert rfc822-to-8bit (ORCPT ); Tue, 4 Nov 2014 03:50:23 -0500 Message-Id: <5458A15A0200007800044A9A@mail.emea.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.0.1 Date: Tue, 04 Nov 2014 08:50:18 +0000 From: "Jan Beulich" To: , , Cc: Subject: [PATCH 1/2] x86-64: handle PC-relative relocations on per-CPU data Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is in preparation of using RIP-relative addressing in many of the per-CPU accesses. Signed-off-by: Jan Beulich --- arch/x86/boot/compressed/misc.c | 14 +++++++++++++- arch/x86/tools/relocs.c | 38 ++++++++++++++++++++++++++++---------- 2 files changed, 41 insertions(+), 11 deletions(-) --- 3.18-rc3-x86_64-PCrel-per-CPU.orig/arch/x86/boot/compressed/misc.c +++ 3.18-rc3-x86_64-PCrel-per-CPU/arch/x86/boot/compressed/misc.c @@ -260,7 +260,7 @@ static void handle_relocations(void *out /* * Process relocations: 32 bit relocations first then 64 bit after. - * Two sets of binary relocations are added to the end of the kernel + * Three sets of binary relocations are added to the end of the kernel * before compression. Each relocation table entry is the kernel * address of the location which needs to be updated stored as a * 32-bit value which is sign extended to 64 bits. @@ -270,6 +270,8 @@ static void handle_relocations(void *out * kernel bits... * 0 - zero terminator for 64 bit relocations * 64 bit relocation repeated + * 0 - zero terminator for inverse 32 bit relocations + * 32 bit inverse relocation repeated * 0 - zero terminator for 32 bit relocations * 32 bit relocation repeated * @@ -286,6 +288,16 @@ static void handle_relocations(void *out *(uint32_t *)ptr += delta; } #ifdef CONFIG_X86_64 + while (*--reloc) { + long extended = *reloc; + extended += map; + + ptr = (unsigned long)extended; + if (ptr < min_addr || ptr > max_addr) + error("inverse 32-bit relocation outside of kernel!\n"); + + *(int32_t *)ptr -= delta; + } for (reloc--; *reloc; reloc--) { long extended = *reloc; extended += map; --- 3.18-rc3-x86_64-PCrel-per-CPU.orig/arch/x86/tools/relocs.c +++ 3.18-rc3-x86_64-PCrel-per-CPU/arch/x86/tools/relocs.c @@ -20,7 +20,10 @@ struct relocs { static struct relocs relocs16; static struct relocs relocs32; +#if ELF_BITS == 64 +static struct relocs relocs32neg; static struct relocs relocs64; +#endif struct section { Elf_Shdr shdr; @@ -762,11 +765,16 @@ static int do_reloc64(struct section *se switch (r_type) { case R_X86_64_NONE: + /* NONE can be ignored. */ + break; + case R_X86_64_PC32: /* - * NONE can be ignored and PC relative relocations don't - * need to be adjusted. + * PC relative relocations don't need to be adjusted unless + * referencing a percpu symbol. */ + if (is_percpu_sym(sym, symname)) + add_reloc(&relocs32neg, offset); break; case R_X86_64_32: @@ -986,7 +994,10 @@ static void emit_relocs(int as_text, int /* Order the relocations for more efficient processing */ sort_relocs(&relocs16); sort_relocs(&relocs32); +#if ELF_BITS == 64 + sort_relocs(&relocs32neg); sort_relocs(&relocs64); +#endif /* Print the relocations */ if (as_text) { @@ -1007,14 +1018,21 @@ static void emit_relocs(int as_text, int for (i = 0; i < relocs32.count; i++) write_reloc(relocs32.offset[i], stdout); } else { - if (ELF_BITS == 64) { - /* Print a stop */ - write_reloc(0, stdout); - - /* Now print each relocation */ - for (i = 0; i < relocs64.count; i++) - write_reloc(relocs64.offset[i], stdout); - } +#if ELF_BITS == 64 + /* Print a stop */ + write_reloc(0, stdout); + + /* Now print each relocation */ + for (i = 0; i < relocs64.count; i++) + write_reloc(relocs64.offset[i], stdout); + + /* Print a stop */ + write_reloc(0, stdout); + + /* Now print each inverse 32-bit relocation */ + for (i = 0; i < relocs32neg.count; i++) + write_reloc(relocs32neg.offset[i], stdout); +#endif /* Print a stop */ write_reloc(0, stdout);