The following commit has been merged into the x86/entry branch of tip: Commit-ID: c182487da1b5281463f2255d2347885dba219c08 Gitweb: https://git.kernel.org/tip/c182487da1b5281463f2255d2347885dba219c08 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Wed, 02 Sep 2020 15:25:52 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Fri, 04 Sep 2020 15:12:52 +02:00 x86/debug: Sync BTF earlier Move the BTF sync near the DR6 load, as this will be the only common code guaranteed to run on every #DB. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Tested-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Acked-by: Andy Lutomirski <luto@xxxxxxxxxx> Link: https://lore.kernel.org/r/20200902133200.786888252@xxxxxxxxxxxxx --- arch/x86/kernel/traps.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 81a2fb7..9945642 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -749,6 +749,13 @@ static __always_inline unsigned long debug_read_clear_dr6(void) /* Filter out all the reserved bits which are preset to 1 */ dr6 &= ~DR6_RESERVED; + /* + * The SDM says "The processor clears the BTF flag when it + * generates a debug exception." Clear TIF_BLOCKSTEP to keep + * TIF_BLOCKSTEP in sync with the hardware BTF flag. + */ + clear_thread_flag(TIF_BLOCKSTEP); + return dr6; } @@ -783,13 +790,6 @@ static void handle_debug(struct pt_regs *regs, unsigned long dr6, bool user) int si_code; /* - * The SDM says "The processor clears the BTF flag when it - * generates a debug exception." Clear TIF_BLOCKSTEP to keep - * TIF_BLOCKSTEP in sync with the hardware BTF flag. - */ - clear_thread_flag(TIF_BLOCKSTEP); - - /* * If DR6 is zero, no point in trying to handle it. The kernel is * not using INT1. */
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