summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/idt.c
diff options
context:
space:
mode:
authorRick Edgecombe <rick.p.edgecombe@intel.com>2023-06-12 17:10:53 -0700
committerDave Hansen <dave.hansen@linux.intel.com>2023-08-02 15:01:50 -0700
commita5f6c2ace9974adf92ce65dacca8126d90adabfe (patch)
tree6516a36961fbbbc4bb435cf5df6dee4b06289060 /arch/x86/kernel/idt.c
parent98cfa4630912a80a575277d1bf193376ba66116a (diff)
x86/shstk: Add user control-protection fault handler
A control-protection fault is triggered when a control-flow transfer attempt violates Shadow Stack or Indirect Branch Tracking constraints. For example, the return address for a RET instruction differs from the copy on the shadow stack. There already exists a control-protection fault handler for handling kernel IBT faults. Refactor this fault handler into separate user and kernel handlers, like the page fault handler. Add a control-protection handler for usermode. To avoid ifdeffery, put them both in a new file cet.c, which is compiled in the case of either of the two CET features supported in the kernel: kernel IBT or user mode shadow stack. Move some static inline functions from traps.c into a header so they can be used in cet.c. Opportunistically fix a comment in the kernel IBT part of the fault handler that is on the end of the line instead of preceding it. Keep the same behavior for the kernel side of the fault handler, except for converting a BUG to a WARN in the case of a #CP happening when the feature is missing. This unifies the behavior with the new shadow stack code, and also prevents the kernel from crashing under this situation which is potentially recoverable. The control-protection fault handler works in a similar way as the general protection fault handler. It provides the si_code SEGV_CPERR to the signal handler. Co-developed-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Tested-by: Pengfei Xu <pengfei.xu@intel.com> Tested-by: John Allen <john.allen@amd.com> Tested-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/all/20230613001108.3040476-28-rick.p.edgecombe%40intel.com
Diffstat (limited to 'arch/x86/kernel/idt.c')
-rw-r--r--arch/x86/kernel/idt.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index a58c6bc1cd68..5074b8420359 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -107,7 +107,7 @@ static const __initconst struct idt_data def_idts[] = {
ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
#endif
-#ifdef CONFIG_X86_KERNEL_IBT
+#ifdef CONFIG_X86_CET
INTG(X86_TRAP_CP, asm_exc_control_protection),
#endif