[PATCH 1/3] X86: make VDSO data support multiple pages

[Shaohua Li]

Currently vdso data is one page. Next patches will add per-cpu data to
vdso, which requires several pages if CPU number is big. This makes VDSO
data support multiple pages.

Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Shaohua Li <shli@xxxxxx>
---
 arch/x86/include/asm/vvar.h     | 6 +++++-
 arch/x86/kernel/asm-offsets.c   | 5 +++++
 arch/x86/kernel/vmlinux.lds.S   | 4 +---
 arch/x86/vdso/vdso-layout.lds.S | 5 +++--
 arch/x86/vdso/vma.c             | 3 ++-
 5 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 5d2b9ad..fcbe621 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -47,7 +47,11 @@ extern char __vvar_page;
 DECLARE_VVAR(0, volatile unsigned long, jiffies)
 DECLARE_VVAR(16, int, vgetcpu_mode)
 DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data)
-
+/*
+ * you must update VVAR_TOTAL_SIZE to reflect all of the variables we're
+ * stuffing into the vvar area.  Don't change any of the above without
+ * also changing this math of VVAR_TOTAL_SIZE
+ */
 #undef DECLARE_VVAR
 
 #endif
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 9f6b934..0ab31a9 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -16,6 +16,7 @@
 #include <asm/sigframe.h>
 #include <asm/bootparam.h>
 #include <asm/suspend.h>
+#include <asm/vgtod.h>
 
 #ifdef CONFIG_XEN
 #include <xen/interface/xen.h>
@@ -71,4 +72,8 @@ void common(void) {
 
 	BLANK();
 	DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
+
+	BLANK();
+	DEFINE(VVAR_TOTAL_SIZE,
+		ALIGN(128 + sizeof(struct vsyscall_gtod_data), PAGE_SIZE));
 }
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 49edf2d..8b11307 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -168,11 +168,9 @@ SECTIONS
 		 * Pad the rest of the page with zeros.  Otherwise the loader
 		 * can leave garbage here.
 		 */
-		. = __vvar_beginning_hack + PAGE_SIZE;
+		. = __vvar_beginning_hack + VVAR_TOTAL_SIZE;
 	} :data
 
-       . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
-
 	/* Init code and data - will be freed after init */
 	. = ALIGN(PAGE_SIZE);
 	.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S
index de2c921..acaf8ce 100644
--- a/arch/x86/vdso/vdso-layout.lds.S
+++ b/arch/x86/vdso/vdso-layout.lds.S
@@ -1,4 +1,5 @@
 #include <asm/vdso.h>
+#include <asm/asm-offsets.h>
 
 /*
  * Linker script for vDSO.  This is an ELF shared object prelinked to
@@ -25,7 +26,7 @@ SECTIONS
 	 * segment.
 	 */
 
-	vvar_start = . - 2 * PAGE_SIZE;
+	vvar_start = . - (VVAR_TOTAL_SIZE + PAGE_SIZE);
 	vvar_page = vvar_start;
 
 	/* Place all vvars at the offsets in asm/vvar.h. */
@@ -35,7 +36,7 @@ SECTIONS
 #undef __VVAR_KERNEL_LDS
 #undef EMIT_VVAR
 
-	hpet_page = vvar_start + PAGE_SIZE;
+	hpet_page = vvar_start + VVAR_TOTAL_SIZE;
 
 	. = SIZEOF_HEADERS;
 
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 970463b..fc37067 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -16,6 +16,7 @@
 #include <asm/vdso.h>
 #include <asm/page.h>
 #include <asm/hpet.h>
+#include <asm/asm-offsets.h>
 
 #if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso64_enabled = 1;
@@ -150,7 +151,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
 		ret = remap_pfn_range(vma,
 				      text_start + image->sym_vvar_page,
 				      __pa_symbol(&__vvar_page) >> PAGE_SHIFT,
-				      PAGE_SIZE,
+				      VVAR_TOTAL_SIZE,
 				      PAGE_READONLY);
 
 	if (ret)
-- 
1.8.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/