[PATCH] x86/x86_64: mark rodata section read-only: make some datastructures const

Mark some key kernel datastructures readonly.  This patch was previously
posted on Jun 28th but was back then not merged because nothing was enforcing
rodata anyway..  well that changed now :)

Patch by Christoph Lameter <christoph@lameter.com> and Dave Jones
<davej@redhat.com>

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index e50b931..607c060 100644 (file)
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -657,6 +657,7 @@ ENTRY(spurious_interrupt_bug)
        pushl $do_spurious_interrupt_bug
        jmp error_code
 
+.section .rodata,"a"
 #include "syscall_table.S"
 
 syscall_table_size=(.-sys_call_table)

diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index 9b21a31..f7ba4ac 100644 (file)
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -1,4 +1,3 @@
-.data
 ENTRY(sys_call_table)
        .long sys_restart_syscall       /* 0 - old "setup()" system call, used for restarting */
        .long sys_exit

diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index e0eb0c7..df0773c 100644 (file)
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -341,7 +341,7 @@ ENTRY(ia32_ptregs_common)
        jmp  ia32_sysret        /* misbalances the return cache */
        CFI_ENDPROC
 
-       .data
+       .section .rodata,"a"
        .align 8
        .globl ia32_sys_call_table
 ia32_sys_call_table:

diff --git a/arch/x86_64/kernel/syscall.c b/arch/x86_64/kernel/syscall.c
index e263685..7c176b3 100644 (file)
--- a/arch/x86_64/kernel/syscall.c
+++ b/arch/x86_64/kernel/syscall.c
@@ -19,7 +19,7 @@ typedef void (*sys_call_ptr_t)(void);
 
 extern void sys_ni_syscall(void);
 
-sys_call_ptr_t sys_call_table[__NR_syscall_max+1] __cacheline_aligned = { 
+const sys_call_ptr_t sys_call_table[__NR_syscall_max+1] = {
        /* Smells like a like a compiler bug -- it doesn't work when the & below is removed. */ 
        [0 ... __NR_syscall_max] = &sys_ni_syscall,
 #include <asm-x86_64/unistd.h>