arm64, vdso: Define vdso_{start,end} as array

Adjust vdso_{start|end} to be char arrays to avoid compile-time analysis
that flags "too large" memcmp() calls with CONFIG_FORTIFY_SOURCE.

Cc: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 41b6e31f8f556f4d4af8ecdafd3867e540a8ed10..ae35f1855e0663a13f8553a47cd59a9521ffc7f9 100644 (file)
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -37,7 +37,7 @@
 #include <asm/vdso.h>
 #include <asm/vdso_datapage.h>
 
-extern char vdso_start, vdso_end;
+extern char vdso_start[], vdso_end[];
 static unsigned long vdso_pages __ro_after_init;
 
 /*
@@ -125,14 +125,14 @@ static int __init vdso_init(void)
        struct page **vdso_pagelist;
        unsigned long pfn;
 
-       if (memcmp(&vdso_start, "\177ELF", 4)) {
+       if (memcmp(vdso_start, "\177ELF", 4)) {
                pr_err("vDSO is not a valid ELF object!\n");
                return -EINVAL;
        }
 
-       vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
+       vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
        pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
-               vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data);
+               vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);
 
        /* Allocate the vDSO pagelist, plus a page for the data. */
        vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
@@ -145,7 +145,7 @@ static int __init vdso_init(void)
 
 
        /* Grab the vDSO code pages. */
-       pfn = sym_to_pfn(&vdso_start);
+       pfn = sym_to_pfn(vdso_start);
 
        for (i = 0; i < vdso_pages; i++)
                vdso_pagelist[i + 1] = pfn_to_page(pfn + i);