From 02fdcd5eac9d653d1addbd69b0c58d73650e1c00 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Fri, 3 Jul 2015 12:44:24 -0700 Subject: [PATCH] x86/traps, context_tracking: Assert that we're in CONTEXT_KERNEL in exception entries Other than the super-atomic exception entries, all exception entries are supposed to switch our context tracking state to CONTEXT_KERNEL. Assert that they do. These assertions appear trivial at this point, as exception_enter() is the function responsible for switching context, but I'm planning on reworking x86's exception context tracking, and these assertions will help make sure that all of this code keeps working. Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/20fa1ee2d943233a184aaf96ff75394d3b34dfba.1435952415.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/traps.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index f5791927aa64..2a783c4fe0e9 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -292,6 +292,8 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str, enum ctx_state prev_state = exception_enter(); siginfo_t info; + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); + if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) != NOTIFY_STOP) { conditional_sti(regs); @@ -376,6 +378,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) siginfo_t *info; prev_state = exception_enter(); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); if (notify_die(DIE_TRAP, "bounds", regs, error_code, X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP) goto exit; @@ -457,6 +460,7 @@ do_general_protection(struct pt_regs *regs, long error_code) enum ctx_state prev_state; prev_state = exception_enter(); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); conditional_sti(regs); if (v8086_mode(regs)) { @@ -514,6 +518,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) return; prev_state = ist_enter(regs); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, SIGTRAP) == NOTIFY_STOP) @@ -750,6 +755,7 @@ dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) enum ctx_state prev_state; prev_state = exception_enter(); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); math_error(regs, error_code, X86_TRAP_MF); exception_exit(prev_state); } @@ -760,6 +766,7 @@ do_simd_coprocessor_error(struct pt_regs *regs, long error_code) enum ctx_state prev_state; prev_state = exception_enter(); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); math_error(regs, error_code, X86_TRAP_XF); exception_exit(prev_state); } @@ -776,6 +783,7 @@ do_device_not_available(struct pt_regs *regs, long error_code) enum ctx_state prev_state; prev_state = exception_enter(); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); BUG_ON(use_eager_fpu()); #ifdef CONFIG_MATH_EMULATION @@ -805,6 +813,7 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) enum ctx_state prev_state; prev_state = exception_enter(); + CT_WARN_ON(ct_state() != CONTEXT_KERNEL); local_irq_enable(); info.si_signo = SIGILL; -- 2.20.1