From: Igor Munkin via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Sergey Kaplun <skaplun@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH luajit 1/2] Add support for full-range 64 bit lightuserdata. Date: Sun, 1 Aug 2021 13:36:15 +0300 [thread overview] Message-ID: <20210801103615.GW27855@tarantool.org> (raw) In-Reply-To: <YQFNrNhjNLAvtQ5M@root> Sergey, Thanks for the fixes and comments! LGTM then, except the three typos I've missed in the previous review. On 28.07.21, Sergey Kaplun wrote: > Igor, > Thanks for the review! > <snipped> > > The new commit message is the following: > > =================================================================== > Add support for full-range 64 bit lightuserdata. > > (cherry picked from commit e9af1abec542e6f9851ff2368e7f196b6382a44c) > > LuaJIT uses special NaN-tagging technique to store internal type on > the Lua stack. In case LJ_GC64 first 13 bits are set in special NaN > type (0xfff8...). FPU generates the only one type. The next 4 bits are > used for an internal LuaJIT type of object on stack. The next 47 bits > are used for storing this object's content. For userdata, it is its > address. In case arm64 the pointer can have more than 47 significant > bits [1]. In this case the error BADLU error is raised. > > For the support of full 64-bit range lightuserdata pointers two new > fields in GCState are added: > > `lightudseg` - vector of segments of lightuserdata. Each element keeps > 32-bit value. 25 MSB equal to MSB of lightuserdata address, the rest are > filled with zeros. The lentgh of the vector is power of 2. Typo: s/lentgh/length/. > > `lightudnum` - the length - 1 of aforementioned vector (up to 255). > > When lightuserdata is pushed on the stack, if its segment is not stored > in vector new value is appended on top of this vector. The maximum > amount of segments is 256. BADLU error is raised in case when user tried Typo: s/tried/tries/. > to add userdata with the new 257-th segment, so the whole VA-space > isn't covered by this patch. > > Also, in this patch all internal usage of lightuserdata (for hooks, > profilers, built-in package, IR and so on) is changed to special values > on Lua Stack. > > Also, conversion of TValue to FFI C type with store is no longer > compiled for lightuserdata. > > [1]: https://www.kernel.org/doc/html/latest/arm64/memory.html > > Sergey Kaplun: > * added the description and the test for the problem > > Resolves tarantool/tarantool#2712 > Needed for tarantool/tarantool#6154 Minor: Why #5629 is not mentioned? > =================================================================== > <snipped> > > See the iterative patch below. > > =================================================================== <snipped> > diff --git a/test/tarantool-tests/lj-49-bad-lightuserdata/testlightuserdata.c b/test/tarantool-tests/lj-49-bad-lightuserdata/testlightuserdata.c > index 801c7fe1..c958841f 100644 > --- a/test/tarantool-tests/lj-49-bad-lightuserdata/testlightuserdata.c > +++ b/test/tarantool-tests/lj-49-bad-lightuserdata/testlightuserdata.c <snipped> > @@ -26,8 +34,8 @@ static int longptr(lua_State *L) > * equals -1. Typo: s/hint equals -1/hint that equals to -1/. > */ > const size_t pagesize = getpagesize(); > - void *mmaped = mmap(START, pagesize, PROT_NONE, > - MAP_PRIVATE | MAP_ANON, -1, 0); > + void *mmaped = mmap(START, pagesize, PROT_NONE, MAP_PRIVATE | MAP_ANON, > + -1, 0); > if (mmaped != MAP_FAILED) { > lua_pushlightuserdata(L, mmaped); > assert(mmaped == lua_topointer(L, -1)); <snipped> > =================================================================== > <snipped> > > -- > Best regards, > Sergey Kaplun -- Best regards, IM
next prev parent reply other threads:[~2021-08-01 10:59 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-06 17:40 [Tarantool-patches] [PATCH luajit 0/2] arm64: fix 48-bit addresses issues Sergey Kaplun via Tarantool-patches 2021-07-06 17:40 ` [Tarantool-patches] [PATCH luajit 1/2] Add support for full-range 64 bit lightuserdata Sergey Kaplun via Tarantool-patches 2021-07-27 13:59 ` Igor Munkin via Tarantool-patches 2021-07-28 12:29 ` Sergey Kaplun via Tarantool-patches 2021-08-01 10:36 ` Igor Munkin via Tarantool-patches [this message] 2021-08-02 14:56 ` Sergey Kaplun via Tarantool-patches 2021-08-01 16:25 ` Sergey Ostanevich via Tarantool-patches 2021-08-02 14:51 ` Sergey Kaplun via Tarantool-patches 2021-08-02 15:42 ` Igor Munkin via Tarantool-patches 2021-08-10 16:46 ` Sergey Ostanevich via Tarantool-patches 2021-08-11 5:54 ` Vitaliia Ioffe via Tarantool-patches 2021-07-06 17:40 ` [Tarantool-patches] [PATCH luajit 2/2] Linux/ARM64: Make mremap() non-moving due to VA space woes Sergey Kaplun via Tarantool-patches 2021-07-27 15:23 ` Igor Munkin via Tarantool-patches 2021-07-28 12:29 ` Sergey Kaplun via Tarantool-patches 2021-08-01 10:36 ` Igor Munkin via Tarantool-patches 2021-08-01 16:59 ` Sergey Ostanevich via Tarantool-patches 2021-08-02 15:08 ` Sergey Kaplun via Tarantool-patches 2021-08-02 15:55 ` Sergey Ostanevich via Tarantool-patches 2021-08-02 15:11 ` Sergey Kaplun via Tarantool-patches 2021-08-11 7:21 ` [Tarantool-patches] [PATCH luajit 0/2] arm64: fix 48-bit addresses issues Igor Munkin via Tarantool-patches
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