Messages in this thread Patch in this message | | | Date | Fri, 21 Aug 2020 11:39:17 +0200 | From | Peter Zijlstra <> | Subject | [PATCH v2 5/8] x86/debug: Simplify #DB signal code |
| |
Get rid of the two variables, avoid computing si_code when not needed and be consistent about which dr6 value is used.
This makes it easier to shuffle code around later.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/kernel/traps.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)
--- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -786,15 +786,6 @@ static __always_inline unsigned long deb static void handle_debug(struct pt_regs *regs, unsigned long dr6) { struct task_struct *tsk = current; - bool user_icebp; - int si_code; - - /* - * If dr6 has no reason to give us about the origin of this trap, - * then it's very likely the result of an icebp/int01 trap. - * User wants a sigtrap for that. - */ - user_icebp = !dr6; /* Store the virtualized DR6 value */ tsk->thread.debugreg6 = dr6; @@ -813,6 +804,11 @@ static void handle_debug(struct pt_regs goto out; } + /* + * Reload dr6, the notifier might have changed it. + */ + dr6 = tsk->thread.debugreg6; + if (WARN_ON_ONCE((dr6 & DR_STEP) && !user_mode(regs))) { /* * Historical junk that used to handle SYSENTER single-stepping. @@ -825,9 +821,13 @@ static void handle_debug(struct pt_regs regs->flags &= ~X86_EFLAGS_TF; } - si_code = get_si_code(tsk->thread.debugreg6); - if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp) - send_sigtrap(regs, 0, si_code); + /* + * If dr6 has no reason to give us about the origin of this trap, + * then it's very likely the result of an icebp/int01 trap. + * User wants a sigtrap for that. + */ + if (dr6 & (DR_STEP | DR_TRAP_BITS) || !dr6) + send_sigtrap(regs, 0, get_si_code(dr6)); out: cond_local_irq_disable(regs);
| |