x86: implement x86_32 stack protector

[mirror_ubuntu-artful-kernel.git] / arch / x86 / kernel / cpu / common.c

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 41b0de6df873375a883dd4bf4a05a3a5c9d58308..260fe4cb2c824df9d8c2df963e52539cec0486ae 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -39,6 +39,7 @@
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/hypervisor.h>
+#include <asm/stackprotector.h>
 
 #include "cpu.h"
 
@@ -122,6 +123,7 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
 
        [GDT_ENTRY_ESPFIX_SS] = { { { 0x00000000, 0x00c09200 } } },
        [GDT_ENTRY_PERCPU] = { { { 0x0000ffff, 0x00cf9200 } } },
+       GDT_STACK_CANARY_INIT
 #endif
 } };
 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
@@ -261,6 +263,7 @@ void load_percpu_segment(int cpu)
        loadsegment(gs, 0);
        wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));
 #endif
+       load_stack_canary_segment();
 }
 
 /* Current gdt points %fs at the "master" per-cpu area: after this,
@@ -946,16 +949,21 @@ unsigned long kernel_eflags;
  */
 DEFINE_PER_CPU(struct orig_ist, orig_ist);
 
-#else
+#else  /* x86_64 */
+
+#ifdef CONFIG_CC_STACKPROTECTOR
+DEFINE_PER_CPU(unsigned long, stack_canary);
+#endif
 
-/* Make sure %fs is initialized properly in idle threads */
+/* Make sure %fs and %gs are initialized properly in idle threads */
 struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
 {
        memset(regs, 0, sizeof(struct pt_regs));
        regs->fs = __KERNEL_PERCPU;
+       regs->gs = __KERNEL_STACK_CANARY;
        return regs;
 }
-#endif
+#endif /* x86_64 */
 
 /*
  * cpu_init() initializes state that is per-CPU. Some data is already
@@ -1120,9 +1128,6 @@ void __cpuinit cpu_init(void)
        __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
 #endif
 
-       /* Clear %gs. */
-       asm volatile ("mov %0, %%gs" : : "r" (0));
-
        /* Clear all 6 debug registers: */
        set_debugreg(0, 0);
        set_debugreg(0, 1);