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Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 76dcd9d8e0bc..8e13ecb41bee 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -18,6 +18,7 @@
#include <asm/pgalloc.h> /* pgd_*(), ... */
#include <asm/kmemcheck.h> /* kmemcheck_*(), ... */
#include <asm/fixmap.h> /* VSYSCALL_START */
+#include <asm/rcu.h> /* exception_enter(), ... */
/*
* Page fault error code bits:
@@ -995,13 +996,24 @@ static int fault_in_kernel_space(unsigned long address)
return address >= TASK_SIZE_MAX;
}
+static inline bool smap_violation(int error_code, struct pt_regs *regs)
+{
+ if (error_code & PF_USER)
+ return false;
+
+ if (!user_mode_vm(regs) && (regs->flags & X86_EFLAGS_AC))
+ return false;
+
+ return true;
+}
+
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*/
-dotraplinkage void __kprobes
-do_page_fault(struct pt_regs *regs, unsigned long error_code)
+static void __kprobes
+__do_page_fault(struct pt_regs *regs, unsigned long error_code)
{
struct vm_area_struct *vma;
struct task_struct *tsk;
@@ -1088,6 +1100,13 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
if (unlikely(error_code & PF_RSVD))
pgtable_bad(regs, error_code, address);
+ if (static_cpu_has(X86_FEATURE_SMAP)) {
+ if (unlikely(smap_violation(error_code, regs))) {
+ bad_area_nosemaphore(regs, error_code, address);
+ return;
+ }
+ }
+
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
/*
@@ -1201,6 +1220,7 @@ good_area:
/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
* of starvation. */
flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ flags |= FAULT_FLAG_TRIED;
goto retry;
}
}
@@ -1209,3 +1229,11 @@ good_area:
up_read(&mm->mmap_sem);
}
+
+dotraplinkage void __kprobes
+do_page_fault(struct pt_regs *regs, unsigned long error_code)
+{
+ exception_enter(regs);
+ __do_page_fault(regs, error_code);
+ exception_exit(regs);
+}