[POWERPC] Support feature fixups in modules

This patch adds support for feature fixups in modules. This involves
adding support for R_PPC64_REL64 relocs to the 64 bits module loader.
It also modifies modpost.c to ignore the powerpc fixup sections (or it
would warn when used in .init.text).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index 92f4e5f..e2c3c6a 100644 (file)
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -24,6 +24,8 @@
 #include <linux/kernel.h>
 #include <linux/cache.h>
 
+#include "setup.h"
+
 #if 0
 #define DEBUGP printk
 #else
@@ -269,33 +271,50 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
        return 0;
 }
 
+static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
+                                   const Elf_Shdr *sechdrs,
+                                   const char *name)
+{
+       char *secstrings;
+       unsigned int i;
+
+       secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+       for (i = 1; i < hdr->e_shnum; i++)
+               if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
+                       return &sechdrs[i];
+       return NULL;
+}
+
 int module_finalize(const Elf_Ehdr *hdr,
                    const Elf_Shdr *sechdrs,
                    struct module *me)
 {
-       char *secstrings;
-       unsigned int i;
+       const Elf_Shdr *sect;
 
        me->arch.bug_table = NULL;
        me->arch.num_bugs = 0;
 
        /* Find the __bug_table section, if present */
-       secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
-       for (i = 1; i < hdr->e_shnum; i++) {
-               if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))
-                       continue;
-               me->arch.bug_table = (void *) sechdrs[i].sh_addr;
-               me->arch.num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);
-               break;
+       sect = find_section(hdr, sechdrs, "__bug_table");
+       if (sect != NULL) {
+               me->arch.bug_table = (void *) sect->sh_addr;
+               me->arch.num_bugs = sect->sh_size / sizeof(struct bug_entry);
        }
 
-       /*
+       /*
         * Strictly speaking this should have a spinlock to protect against
         * traversals, but since we only traverse on BUG()s, a spinlock
         * could potentially lead to deadlock and thus be counter-productive.
         */
        list_add(&me->arch.bug_list, &module_bug_list);
 
+       /* Apply feature fixups */
+       sect = find_section(hdr, sechdrs, "__ftr_fixup");
+       if (sect != NULL)
+               do_feature_fixups(cur_cpu_spec->cpu_features,
+                                 (void *)sect->sh_addr,
+                                 (void *)sect->sh_addr + sect->sh_size);
+
        return 0;
 }
 

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index ba34001..8dd1f0a 100644 (file)
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -22,6 +22,9 @@
 #include <linux/vmalloc.h>
 #include <asm/module.h>
 #include <asm/uaccess.h>
+#include <asm/firmware.h>
+
+#include "setup.h"
 
 /* FIXME: We don't do .init separately.  To do this, we'd need to have
    a separate r2 value in the init and core section, and stub between
@@ -400,6 +403,11 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
                                | (value & 0x03fffffc);
                        break;
 
+               case R_PPC64_REL64:
+                       /* 64 bits relative (used by features fixups) */
+                       *location = value - (unsigned long)location;
+                       break;
+
                default:
                        printk("%s: Unknown ADD relocation: %lu\n",
                               me->name,
@@ -413,23 +421,33 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 
 LIST_HEAD(module_bug_list);
 
-int module_finalize(const Elf_Ehdr *hdr,
-               const Elf_Shdr *sechdrs, struct module *me)
+static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
+                                   const Elf_Shdr *sechdrs,
+                                   const char *name)
 {
        char *secstrings;
        unsigned int i;
 
+       secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+       for (i = 1; i < hdr->e_shnum; i++)
+               if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
+                       return &sechdrs[i];
+       return NULL;
+}
+
+int module_finalize(const Elf_Ehdr *hdr,
+               const Elf_Shdr *sechdrs, struct module *me)
+{
+       const Elf_Shdr *sect;
+
        me->arch.bug_table = NULL;
        me->arch.num_bugs = 0;
 
        /* Find the __bug_table section, if present */
-       secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
-       for (i = 1; i < hdr->e_shnum; i++) {
-               if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))
-                       continue;
-               me->arch.bug_table = (void *) sechdrs[i].sh_addr;
-               me->arch.num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);
-               break;
+       sect = find_section(hdr, sechdrs, "__bug_table");
+       if (sect != NULL) {
+               me->arch.bug_table = (void *) sect->sh_addr;
+               me->arch.num_bugs = sect->sh_size / sizeof(struct bug_entry);
        }
 
        /*
@@ -439,6 +457,19 @@ int module_finalize(const Elf_Ehdr *hdr,
         */
        list_add(&me->arch.bug_list, &module_bug_list);
 
+       /* Apply feature fixups */
+       sect = find_section(hdr, sechdrs, "__ftr_fixup");
+       if (sect != NULL)
+               do_feature_fixups(cur_cpu_spec->cpu_features,
+                                 (void *)sect->sh_addr,
+                                 (void *)sect->sh_addr + sect->sh_size);
+
+       sect = find_section(hdr, sechdrs, "__fw_ftr_fixup");
+       if (sect != NULL)
+               do_feature_fixups(powerpc_firmware_features,
+                                 (void *)sect->sh_addr,
+                                 (void *)sect->sh_addr + sect->sh_size);
+
        return 0;
 }
 

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 4127796..2e11416 100644 (file)
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -921,6 +921,8 @@ static int init_section_ref_ok(const char *name)
                ".fixup",
                ".smp_locks",
                ".plt",  /* seen on ARCH=um build on x86_64. Harmless */
+               "__ftr_fixup",          /* powerpc cpu feature fixup */
+               "__fw_ftr_fixup",       /* powerpc firmware feature fixup */
                NULL
        };
        /* Start of section names */