Commit 75809229 authored by Peter Maydell's avatar Peter Maydell
Browse files

translate-all.c: Don't pass puc, locked to tb_invalidate_phys_page() 



The user-mode-only function tb_invalidate_phys_page() is only
called from two places:
 * page_unprotect(), which passes in a non-zero pc, a puc pointer
   and the value 'true' for the locked argument
 * page_set_flags(), which passes in a zero pc, a NULL puc pointer
   and a 'false' locked argument

If the pc is non-zero then we may call cpu_resume_from_signal(),
which does a longjmp out of the calling code (and out of the
signal handler); this is to cover the case of a target CPU with
"precise self-modifying code" (currently only x86) executing
a store instruction which modifies code in the same TB as the
store itself. Rather than doing the longjump directly here,
return a flag to the caller which indicates whether the current
TB was modified, and move the longjump to page_unprotect.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarSergey Fedorov <sergey.fedorov@linaro.org>
Acked-by: default avatarEduardo Habkost <ehabkost@redhat.com>
Acked-by: default avatarRiku Voipio <riku.voipio@linaro.org>
Message-id: 1463494687-25947-2-git-send-email-peter.maydell@linaro.org
parent 9bbbf649

translate-all.c

+15 −11
Original line number Diff line number Diff line
@@ -1439,10 +1439,13 @@ void tb_invalidate_phys_page_fast(tb_page_addr_t start, int len) 
    }

}

#else

/* Called with mmap_lock held.  */

static void tb_invalidate_phys_page(tb_page_addr_t addr,

                                    uintptr_t pc, void *puc,

                                    bool locked)

/* Called with mmap_lock held. If pc is not 0 then it indicates the

 * host PC of the faulting store instruction that caused this invalidate.

 * Returns true if the caller needs to abort execution of the current

 * TB (because it was modified by this store and the guest CPU has

 * precise-SMC semantics).

 */

static bool tb_invalidate_phys_page(tb_page_addr_t addr, uintptr_t pc)

{

    TranslationBlock *tb;

    PageDesc *p;
@@ -1460,7 +1463,7 @@ static void tb_invalidate_phys_page(tb_page_addr_t addr, 
    addr &= TARGET_PAGE_MASK;

    p = page_find(addr >> TARGET_PAGE_BITS);

    if (!p) {

        return;

        return false;

    }

    tb = p->first_tb;

#ifdef TARGET_HAS_PRECISE_SMC
@@ -1499,12 +1502,10 @@ static void tb_invalidate_phys_page(tb_page_addr_t addr, 
           modifying the memory. It will ensure that it cannot modify

           itself */

        tb_gen_code(cpu, current_pc, current_cs_base, current_flags, 1);

        if (locked) {

            mmap_unlock();

        }

        cpu_resume_from_signal(cpu, puc);

        return true;

    }

#endif

    return false;

}

#endif
@@ -1902,7 +1903,7 @@ void page_set_flags(target_ulong start, target_ulong end, int flags) 
        if (!(p->flags & PAGE_WRITE) &&

            (flags & PAGE_WRITE) &&

            p->first_tb) {

            tb_invalidate_phys_page(addr, 0, NULL, false);

            tb_invalidate_phys_page(addr, 0);

        }

        p->flags = flags;

    }
@@ -1996,7 +1997,10 @@ int page_unprotect(target_ulong address, uintptr_t pc, void *puc) 


            /* and since the content will be modified, we must invalidate

               the corresponding translated code. */

            tb_invalidate_phys_page(addr, pc, puc, true);

            if (tb_invalidate_phys_page(addr, pc)) {

                mmap_unlock();

                cpu_resume_from_signal(current_cpu, puc);

            }

#ifdef DEBUG_TB_CHECK

            tb_invalidate_check(addr);

#endif