Commit 36eb6e09 authored by Richard Henderson's avatar Richard Henderson Committed by Eduardo Habkost
Browse files

target-i386: Re-introduce optimal breakpoint removal 



Before the last patch, we had an efficient loop that disabled
local breakpoints on task switch.  Re-add that, but in a more
general way that handles changes to the global enable bits too.

Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarEduardo Habkost <ehabkost@redhat.com>
parent 93d00d0f

target-i386/bpt_helper.c

+28 −6
Original line number Diff line number Diff line
@@ -82,8 +82,29 @@ static void hw_breakpoint_remove(CPUX86State *env, int index) 


void cpu_x86_update_dr7(CPUX86State *env, uint32_t new_dr7)

{

    target_ulong old_dr7 = env->dr[7];

    int i;



    /* If nothing is changing except the global/local enable bits,

       then we can make the change more efficient.  */

    if (((old_dr7 ^ new_dr7) & ~0xff) == 0) {

        /* Fold the global and local enable bits together into the

           global fields, then xor to show which registers have

           changed collective enable state.  */

        int mod = ((old_dr7 | old_dr7 * 2) ^ (new_dr7 | new_dr7 * 2)) & 0xff;



        for (i = 0; i < DR7_MAX_BP; i++) {

            if ((mod & (2 << i * 2)) && !hw_breakpoint_enabled(new_dr7, i)) {

                hw_breakpoint_remove(env, i);

            }

        }

        env->dr[7] = new_dr7;

        for (i = 0; i < DR7_MAX_BP; i++) {

            if (mod & (2 << i * 2) && hw_breakpoint_enabled(new_dr7, i)) {

                hw_breakpoint_insert(env, i);

            }

        }

    } else {

        for (i = 0; i < DR7_MAX_BP; i++) {

            hw_breakpoint_remove(env, i);

        }
@@ -92,6 +113,7 @@ void cpu_x86_update_dr7(CPUX86State *env, uint32_t new_dr7) 
            hw_breakpoint_insert(env, i);

        }

    }

}

#endif



static bool check_hw_breakpoints(CPUX86State *env, bool force_dr6_update)