On Sun, 18 Aug 2019, Thomas Gleixner wrote:
>
> Patch below. I tested this with the normal order and by installing a
> 'timens' page unconditionally for all processes. I'll reply with the timens
> testing hacks so you can see what I did.
First hack...
Thanks,
tglx
8<-----------------
Subject: x86/vdso: Hack to enable time name space for testing
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Sun, 18 Aug 2019 16:42:26 +0200
Select CONFIG_VDSO_TIMENS and prepare for the extra magic time namespace
vvar page. The fault handler is not handling it yet as the path is never
taken (hopefully)
Not-Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/Kconfig | 1 +
arch/x86/entry/vdso/vdso-layout.lds.S | 3 ++-
arch/x86/entry/vdso/vdso2c.c | 3 +++
arch/x86/include/asm/vdso.h | 1 +
arch/x86/include/asm/vdso/gettimeofday.h | 9 +++++++++
5 files changed, 16 insertions(+), 1 deletion(-)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -224,6 +224,7 @@ config X86
select VIRT_TO_BUS
select X86_FEATURE_NAMES if PROC_FS
select PROC_PID_ARCH_STATUS if PROC_FS
+ select VDSO_TIMENS
config INSTRUCTION_DECODER
def_bool y
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -16,7 +16,7 @@ SECTIONS
* segment.
*/
- vvar_start = . - 3 * PAGE_SIZE;
+ vvar_start = . - 4 * PAGE_SIZE;
vvar_page = vvar_start;
/* Place all vvars at the offsets in asm/vvar.h. */
@@ -28,6 +28,7 @@ SECTIONS
pvclock_page = vvar_start + PAGE_SIZE;
hvclock_page = vvar_start + 2 * PAGE_SIZE;
+ timens_page = vvar_start + 3 * PAGE_SIZE;
. = SIZEOF_HEADERS;
--- a/arch/x86/entry/vdso/vdso2c.c
+++ b/arch/x86/entry/vdso/vdso2c.c
@@ -75,12 +75,14 @@ enum {
sym_vvar_page,
sym_pvclock_page,
sym_hvclock_page,
+ sym_timens_page,
};
const int special_pages[] = {
sym_vvar_page,
sym_pvclock_page,
sym_hvclock_page,
+ sym_timens_page,
};
struct vdso_sym {
@@ -93,6 +95,7 @@ struct vdso_sym required_syms[] = {
[sym_vvar_page] = {"vvar_page", true},
[sym_pvclock_page] = {"pvclock_page", true},
[sym_hvclock_page] = {"hvclock_page", true},
+ [sym_timens_page] = {"timens_page", true},
{"VDSO32_NOTE_MASK", true},
{"__kernel_vsyscall", true},
{"__kernel_sigreturn", true},
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -21,6 +21,7 @@ struct vdso_image {
long sym_vvar_page;
long sym_pvclock_page;
long sym_hvclock_page;
+ long sym_timens_page;
long sym_VDSO32_NOTE_MASK;
long sym___kernel_sigreturn;
long sym___kernel_rt_sigreturn;
--- a/arch/x86/include/asm/vdso/gettimeofday.h
+++ b/arch/x86/include/asm/vdso/gettimeofday.h
@@ -265,6 +265,15 @@ static __always_inline const struct vdso
return __vdso_data;
}
+/* HACK .... */
+#define VDSO_TIMENS_PAGEOFFSET (3 * PAGE_SIZE)
+
+static __always_inline
+const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
+{
+ return (void *)vd + VDSO_TIMENS_PAGEOFFSET;
+}
+
/*
* x86 specific delta calculation.
*
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