powerpc/vdso: Disable building the 32-bit VDSO on little endian

The only little endian configuration we support is ppc64le. As such if
we're building little endian we don't need a 32-bit VDSO, because there
is no 32-bit userspace.

This patch is a fairly ugly mess of #ifdefs, but is the minimal logic
required to disable the 32-bit VDSO. We can hopefully clean up the
result in future with some further refactoring.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 34 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 8331d0bef0fb..b457bfa28436 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -49,13 +49,16 @@
 /* The alignment of the vDSO */
 #define VDSO_ALIGNMENT  (1 << 16)
 
-extern char vdso32_start, vdso32_end;
-static void *vdso32_kbase = &vdso32_start;
 static unsigned int vdso32_pages;
+static void *vdso32_kbase;
 static struct page **vdso32_pagelist;
 unsigned long vdso32_sigtramp;
 unsigned long vdso32_rt_sigtramp;
 
+#ifdef CONFIG_VDSO32
+extern char vdso32_start, vdso32_end;
+#endif
+
 #ifdef CONFIG_PPC64
 extern char vdso64_start, vdso64_end;
 static void *vdso64_kbase = &vdso64_start;
@@ -248,6 +251,7 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 
 
+#ifdef CONFIG_VDSO32
 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
                                   unsigned long *size)
 {
@@ -335,6 +339,20 @@ static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
 
         return 0;
 }
+#else /* !CONFIG_VDSO32 */
+static unsigned long __init find_function32(struct lib32_elfinfo *lib,
+                                            const char *symname)
+{
+        return 0;
+}
+
+static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32,
+                                       struct lib64_elfinfo *v64,
+                                       const char *orig, const char *fix)
+{
+        return 0;
+}
+#endif /* CONFIG_VDSO32 */
 
 
 #ifdef CONFIG_PPC64
@@ -445,6 +463,7 @@ static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
          * Locate symbol tables & text section
          */
 
+#ifdef CONFIG_VDSO32
         v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
         v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
         if (v32->dynsym == NULL || v32->dynstr == NULL) {
@@ -457,6 +476,7 @@ static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
                 return -1;
         }
         v32->text = sect - vdso32_kbase;
+#endif
 
 #ifdef CONFIG_PPC64
         v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
@@ -493,7 +513,9 @@ static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
                                        struct lib64_elfinfo *v64)
 {
+#ifdef CONFIG_VDSO32
         Elf32_Sym *sym32;
+#endif
 #ifdef CONFIG_PPC64
         Elf64_Sym *sym64;
 
@@ -508,6 +530,7 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
                 (sym64->st_value - VDSO64_LBASE);
 #endif /* CONFIG_PPC64 */
 
+#ifdef CONFIG_VDSO32
         sym32 = find_symbol32(v32, "__kernel_datapage_offset");
         if (sym32 == NULL) {
                 printk(KERN_ERR "vDSO32: Can't find symbol "
@@ -517,6 +540,7 @@ static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
         *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
                 (vdso32_pages << PAGE_SHIFT) -
                 (sym32->st_value - VDSO32_LBASE);
+#endif
 
         return 0;
 }
@@ -550,6 +574,7 @@ static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
                                  start, start + size);
 #endif /* CONFIG_PPC64 */
 
+#ifdef CONFIG_VDSO32
         start = find_section32(v32->hdr, "__ftr_fixup", &size);
         if (start)
                 do_feature_fixups(cur_cpu_spec->cpu_features,
@@ -571,6 +596,7 @@ static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
         if (start)
                 do_lwsync_fixups(cur_cpu_spec->cpu_features,
                                  start, start + size);
+#endif
 
         return 0;
 }
@@ -732,11 +758,15 @@ static int __init vdso_init(void)
 #endif /* CONFIG_PPC64 */
 
 
+#ifdef CONFIG_VDSO32
+        vdso32_kbase = &vdso32_start;
+
         /*
          * Calculate the size of the 32 bits vDSO
          */
         vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
         DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
+#endif
 
 
         /*
@@ -757,6 +787,7 @@ static int __init vdso_init(void)
                 return 0;
         }
 
+#ifdef CONFIG_VDSO32
         /* Make sure pages are in the correct state */
         vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 2),
                                   GFP_KERNEL);
@@ -769,6 +800,7 @@ static int __init vdso_init(void)
         }
         vdso32_pagelist[i++] = virt_to_page(vdso_data);
         vdso32_pagelist[i] = NULL;
+#endif
 
 #ifdef CONFIG_PPC64
         vdso64_pagelist = kzalloc(sizeof(struct page *) * (vdso64_pages + 2),