On Thu, May 24, 2012 at 6:21 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: > On 2012-05-24 11:11, Max Filippov wrote: >> On Thu, May 24, 2012 at 5:26 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: >>> On 2012-05-24 09:42, Max Filippov wrote: >>>> On Thu, May 24, 2012 at 4:16 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: >>>>> On 2012-05-24 09:08, Max Filippov wrote: >>>>>> On Thu, May 24, 2012 at 3:25 PM, Jan Kiszka <jan.kis...@siemens.com> >>>>>> wrote: >>>>>>> On 2012-05-24 07:51, Max Filippov wrote: >>>>>>>> On Thu, May 24, 2012 at 6:34 AM, Jan Kiszka <jan.kis...@web.de> wrote: >>>>>>>>> From: Jan Kiszka <jan.kis...@siemens.com> >>>>>>>>> >>>>>>>>> tb_invalidate_phys_addr has to called with the exact physical address >>>>>>>>> of >>>>>>>>> the breakpoint we add/remove, not just the page's base address. >>>>>>>>> Otherwise we easily fail to flush the right TB. >>>>>>>>> >>>>>>>>> Regression of 1e7855a558. >>>>>>>> >>>>>>>> Sorry, I fail to see how 1e7855a558 could introduce a regression, it >>>>>>>> just rearranged the code. >>>>>>>> Even more, AFAIK cpu_get_phys_page_debug returns complete physical >>>>>>>> address, not just >>>>>>>> physical page. Probably it has a misleading name. >>>>>>> >>>>>>> Unfortunately, cpu_get_phys_page_debug does NOT deliver the sub-page >>>>>>> offset, only the page base address. >>>>>> >>>>>> Ok, i386 has probably the most explicit implementation, >>>>>> let's look at the target-i386/helper.c:876 >>>>>> >>>>>> page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1); >>>>>> paddr = (pte & TARGET_PAGE_MASK) + page_offset; >>>>>> return paddr; >>>>>> >>>>>> that's clearly physical page plus in-page offset. >>>>>> I can provide other samples (: >>>>> >>>>> "page_offset" is misleading: addr & TARGET_PAGE_MASK kills all the >>>>> offset bits. It will only contain the relevant bits between page_size >>>>> and TARGET_PAGE_SIZE. >>>>> >>>>> Check also ppc's cpu_get_phys_page_debug, it's clearer in this regard. >>>> >>>> Ok, for i386, ppc, microblaze (and maybe others) you're right. >>>> What about ARM, CRIS, MIPS, SH4, xtensa (and maybe others)? >>>> Looks like this is a long-standing discrepancy and consequently >>>> a long-standing bug in the breakpoint_invalidate. >>> >>> Not in breakpoint_invalidate as the missing offset was compensated >>> before your commit (well, starting with c2f07f81a2 in fact). >> >> I'd say that compensation that you mention >> >> ram_addr = (memory_region_get_ram_addr(section.mr) >> + section.offset_within_region) & TARGET_PAGE_MASK; >> this >>>> ram_addr |= (pc & ~TARGET_PAGE_MASK); >> tb_invalidate_phys_page_range(ram_addr, ram_addr + 1, 0); >> >> was removed by f3705d53296d, not by 1e7855a558 > > Unless I misinterpret section_addr, it does return the lower address > bits unmodified.
Maybe, but addr = cpu_get_phys_page_debug(env, pc); which should have lost its in-page offset according to you. >> >>> But it looks like cpu_get_phys_page_debug was broken for quite a while. >>> Let's fix those archs to return more than page-aligned addresses. >> >> You mean make them all return full physical address? >> I'd propose to rename the function then as well. > > No, to return the page base address like x86 etc. do and like most if > not all users expect it to. So fix ARM & Co. -- Thanks. -- Max
