[PATCH 2/3] x86_64,vsyscall: Turn vsyscalls all the way off when vsyscall=none

2014-05-22 Thread Andy Lutomirski 
I see no point in having an unusable read-only page sitting at
0xff60 when vsyscall=none.  Instead, skip mapping it and
remove it from /proc/PID/maps.

I kept the ratelimited warning when programs try to use a vsyscall
in this mode, since it may help admins avoid confusion.

Signed-off-by: Andy Lutomirski 
---
 arch/x86/kernel/vsyscall_64.c | 14 +-
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index ad84894..8d38eb5 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -309,6 +309,8 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
if (!mm || mm->context.ia32_compat)
return NULL;
 #endif
+   if (vsyscall_mode == NONE)
+   return NULL;
return _vma;
 }
 
@@ -329,7 +331,7 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr)
  */
 int in_gate_area_no_mm(unsigned long addr)
 {
-   return (addr & PAGE_MASK) == VSYSCALL_ADDR;
+   return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR;
 }
 
 /*
@@ -380,10 +382,12 @@ void __init map_vsyscall(void)
extern char __vsyscall_page;
unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
 
-   __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
-vsyscall_mode == NATIVE
-? PAGE_KERNEL_VSYSCALL
-: PAGE_KERNEL_VVAR);
+   if (vsyscall_mode != NONE)
+   __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
+vsyscall_mode == NATIVE
+? PAGE_KERNEL_VSYSCALL
+: PAGE_KERNEL_VVAR);
+
BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
 (unsigned long)VSYSCALL_ADDR);
 }
-- 
1.9.0

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[PATCH 2/3] x86_64,vsyscall: Turn vsyscalls all the way off when vsyscall=none

2014-05-22 Thread Andy Lutomirski 
I see no point in having an unusable read-only page sitting at
0xff60 when vsyscall=none.  Instead, skip mapping it and
remove it from /proc/PID/maps.

I kept the ratelimited warning when programs try to use a vsyscall
in this mode, since it may help admins avoid confusion.

Signed-off-by: Andy Lutomirski l...@amacapital.net
---
 arch/x86/kernel/vsyscall_64.c | 14 +-
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index ad84894..8d38eb5 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -309,6 +309,8 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
if (!mm || mm-context.ia32_compat)
return NULL;
 #endif
+   if (vsyscall_mode == NONE)
+   return NULL;
return gate_vma;
 }
 
@@ -329,7 +331,7 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr)
  */
 int in_gate_area_no_mm(unsigned long addr)
 {
-   return (addr  PAGE_MASK) == VSYSCALL_ADDR;
+   return vsyscall_mode != NONE  (addr  PAGE_MASK) == VSYSCALL_ADDR;
 }
 
 /*
@@ -380,10 +382,12 @@ void __init map_vsyscall(void)
extern char __vsyscall_page;
unsigned long physaddr_vsyscall = __pa_symbol(__vsyscall_page);
 
-   __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
-vsyscall_mode == NATIVE
-? PAGE_KERNEL_VSYSCALL
-: PAGE_KERNEL_VVAR);
+   if (vsyscall_mode != NONE)
+   __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
+vsyscall_mode == NATIVE
+? PAGE_KERNEL_VSYSCALL
+: PAGE_KERNEL_VVAR);
+
BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
 (unsigned long)VSYSCALL_ADDR);
 }
-- 
1.9.0

--
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Please read the FAQ at  http://www.tux.org/lkml/