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Mon, 25 Jan 2021 09:13:55 -0800 (PST) Received: from [192.168.1.4] ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id k42sm12212685qtk.17.2021.01.25.09.13.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 25 Jan 2021 09:13:54 -0800 (PST) To: Tulio Magno Quites Machado Filho , libc-alpha@sourceware.org Cc: Andreas Schwab , amodra@gmail.com References: <87r1qi2ubi.fsf@igel.home> <20210122012931.1354527-1-tuliom@linux.ibm.com> From: Adhemerval Zanella Autocrypt: addr=adhemerval.zanella@linaro.org; prefer-encrypt=mutual; keydata= mQINBFcVGkoBEADiQU2x/cBBmAVf5C2d1xgz6zCnlCefbqaflUBw4hB/bEME40QsrVzWZ5Nq 8kxkEczZzAOKkkvv4pRVLlLn/zDtFXhlcvQRJ3yFMGqzBjofucOrmdYkOGo0uCaoJKPT186L NWp53SACXguFJpnw4ODI64ziInzXQs/rUJqrFoVIlrPDmNv/LUv1OVPKz20ETjgfpg8MNwG6 iMizMefCl+RbtXbIEZ3TE/IaDT/jcOirjv96lBKrc/pAL0h/O71Kwbbp43fimW80GhjiaN2y WGByepnkAVP7FyNarhdDpJhoDmUk9yfwNuIuESaCQtfd3vgKKuo6grcKZ8bHy7IXX1XJj2X/ BgRVhVgMHAnDPFIkXtP+SiarkUaLjGzCz7XkUn4XAGDskBNfbizFqYUQCaL2FdbW3DeZqNIa nSzKAZK7Dm9+0VVSRZXP89w71Y7JUV56xL/PlOE+YKKFdEw+gQjQi0e+DZILAtFjJLoCrkEX w4LluMhYX/X8XP6/C3xW0yOZhvHYyn72sV4yJ1uyc/qz3OY32CRy+bwPzAMAkhdwcORA3JPb kPTlimhQqVgvca8m+MQ/JFZ6D+K7QPyvEv7bQ7M+IzFmTkOCwCJ3xqOD6GjX3aphk8Sr0dq3 4Awlf5xFDAG8dn8Uuutb7naGBd/fEv6t8dfkNyzj6yvc4jpVxwARAQABtElBZGhlbWVydmFs IFphbmVsbGEgTmV0dG8gKExpbmFybyBWUE4gS2V5KSA8YWRoZW1lcnZhbC56YW5lbGxhQGxp bmFyby5vcmc+iQI3BBMBCAAhBQJXFRpKAhsDBQsJCAcDBRUKCQgLBRYCAwEAAh4BAheAAAoJ EKqx7BSnlIjv0e8P/1YOYoNkvJ+AJcNUaM5a2SA9oAKjSJ/M/EN4Id5Ow41ZJS4lUA0apSXW NjQg3VeVc2RiHab2LIB4MxdJhaWTuzfLkYnBeoy4u6njYcaoSwf3g9dSsvsl3mhtuzm6aXFH /Qsauav77enJh99tI4T+58rp0EuLhDsQbnBic/ukYNv7sQV8dy9KxA54yLnYUFqH6pfH8Lly sTVAMyi5Fg5O5/hVV+Z0Kpr+ZocC1YFJkTsNLAW5EIYSP9ftniqaVsim7MNmodv/zqK0IyDB GLLH1kjhvb5+6ySGlWbMTomt/or/uvMgulz0bRS+LUyOmlfXDdT+t38VPKBBVwFMarNuREU2 69M3a3jdTfScboDd2ck1u7l+QbaGoHZQ8ZNUrzgObltjohiIsazqkgYDQzXIMrD9H19E+8fw kCNUlXxjEgH/Kg8DlpoYJXSJCX0fjMWfXywL6ZXc2xyG/hbl5hvsLNmqDpLpc1CfKcA0BkK+ k8R57fr91mTCppSwwKJYO9T+8J+o4ho/CJnK/jBy1pWKMYJPvvrpdBCWq3MfzVpXYdahRKHI ypk8m4QlRlbOXWJ3TDd/SKNfSSrWgwRSg7XCjSlR7PNzNFXTULLB34sZhjrN6Q8NQZsZnMNs TX8nlGOVrKolnQPjKCLwCyu8PhllU8OwbSMKskcD1PSkG6h3r0AquQINBFcVGkoBEACgAdbR Ck+fsfOVwT8zowMiL3l9a2DP3Eeak23ifdZG+8Avb/SImpv0UMSbRfnw/N81IWwlbjkjbGTu oT37iZHLRwYUFmA8fZX0wNDNKQUUTjN6XalJmvhdz9l71H3WnE0wneEM5ahu5V1L1utUWTyh VUwzX1lwJeV3vyrNgI1kYOaeuNVvq7npNR6t6XxEpqPsNc6O77I12XELic2+36YibyqlTJIQ V1SZEbIy26AbC2zH9WqaKyGyQnr/IPbTJ2Lv0dM3RaXoVf+CeK7gB2B+w1hZummD21c1Laua +VIMPCUQ+EM8W9EtX+0iJXxI+wsztLT6vltQcm+5Q7tY+HFUucizJkAOAz98YFucwKefbkTp eKvCfCwiM1bGatZEFFKIlvJ2QNMQNiUrqJBlW9nZp/k7pbG3oStOjvawD9ZbP9e0fnlWJIsj 6c7pX354Yi7kxIk/6gREidHLLqEb/otuwt1aoMPg97iUgDV5mlNef77lWE8vxmlY0FBWIXuZ yv0XYxf1WF6dRizwFFbxvUZzIJp3spAao7jLsQj1DbD2s5+S1BW09A0mI/1DjB6EhNN+4bDB SJCOv/ReK3tFJXuj/HbyDrOdoMt8aIFbe7YFLEExHpSk+HgN05Lg5TyTro8oW7TSMTk+8a5M kzaH4UGXTTBDP/g5cfL3RFPl79ubXwARAQABiQIfBBgBCAAJBQJXFRpKAhsMAAoJEKqx7BSn lIjvI/8P/jg0jl4Tbvg3B5kT6PxJOXHYu9OoyaHLcay6Cd+ZrOd1VQQCbOcgLFbf4Yr+rE9l mYsY67AUgq2QKmVVbn9pjvGsEaz8UmfDnz5epUhDxC6yRRvY4hreMXZhPZ1pbMa6A0a/WOSt AgFj5V6Z4dXGTM/lNManr0HjXxbUYv2WfbNt3/07Db9T+GZkpUotC6iknsTA4rJi6u2ls0W9 1UIvW4o01vb4nZRCj4rni0g6eWoQCGoVDk/xFfy7ZliR5B+3Z3EWRJcQskip/QAHjbLa3pml xAZ484fVxgeESOoaeC9TiBIp0NfH8akWOI0HpBCiBD5xaCTvR7ujUWMvhsX2n881r/hNlR9g fcE6q00qHSPAEgGr1bnFv74/1vbKtjeXLCcRKk3Ulw0bY1OoDxWQr86T2fZGJ/HIZuVVBf3+ gaYJF92GXFynHnea14nFFuFgOni0Mi1zDxYH/8yGGBXvo14KWd8JOW0NJPaCDFJkdS5hu0VY 7vJwKcyHJGxsCLU+Et0mryX8qZwqibJIzu7kUJQdQDljbRPDFd/xmGUFCQiQAncSilYOcxNU EMVCXPAQTteqkvA+gNqSaK1NM9tY0eQ4iJpo+aoX8HAcn4sZzt2pfUB9vQMTBJ2d4+m/qO6+ cFTAceXmIoFsN8+gFN3i8Is3u12u8xGudcBPvpoy4OoG Subject: Re: [PATCHv2] powerpc64: Implement TLS using PC-relative addressing Message-ID: Date: Mon, 25 Jan 2021 14:13:51 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210122012931.1354527-1-tuliom@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-13.7 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jan 2021 17:14:00 -0000 On 21/01/2021 22:29, Tulio Magno Quites Machado Filho via Libc-alpha wrote: > Changes since v1: > - Dropped the workaround for early GCC 10 versions. We can't get this > code to work without having the macro __PCREL__. The previous code > was failing if -mcpu=power10 -mno-pcrel was used. > - Fixed coding style issues (added space after #defined and removed > unnecessary parenthesis). > > ---8<--- > > As the TOC pointer becomes optional on POWER, TLS access has to be > modified in order to use PC-relative addressing instead of depending on > the TOC pointer availability. > > This patch also changes old TLS code to use the new syntax. It's a > purely aesthetical change: the old code still works and the new syntax > helps to move the argument setup instruction away from the call, which > is not used in an inline assembly. > > Suggested-by: Alan Modra > --- > sysdeps/powerpc/mod-tlsopt-powerpc.c | 7 ++++ > sysdeps/powerpc/powerpc64/tls-macros.h | 54 ++++++++++++++++++++++---- > 2 files changed, 53 insertions(+), 8 deletions(-) > > diff --git a/sysdeps/powerpc/mod-tlsopt-powerpc.c b/sysdeps/powerpc/mod-tlsopt-powerpc.c > index ee0db12a73..ecfa11cb95 100644 > --- a/sysdeps/powerpc/mod-tlsopt-powerpc.c > +++ b/sysdeps/powerpc/mod-tlsopt-powerpc.c > @@ -24,7 +24,14 @@ tls_get_addr_opt_test (void) > tls_index *tls_arg; > #ifdef __powerpc64__ > register unsigned long thread_pointer __asm__ ("r13"); > + /* PC-relative addressing is available when compiling with -mpcrel. > + The first releases of GCC 10 do support -mpcrel, but do not export > + __PCREL__. */ > +# if defined __PCREL__ > + asm ("pla %0,foo@got@tlsgd@pcrel" : "=r" (tls_arg)); > +# else > asm ("addi %0,2,foo@got@tlsgd" : "=r" (tls_arg)); > +# endif > #else > register unsigned long thread_pointer __asm__ ("r2"); > asm ("bcl 20,31,1f\n1:\t" The 'pla/pld' instruction support was added in binutils 2.33 version (PowerPC D-form prefixed loads and stores, commit 8acf14351c8), however the current idea is to set the minimal version for powerpc to 2.29 [1]. The tls-macros.h is used solely for testing and if I understood correctly -mpcrel should not require extra glibc support (so there is no compiling reason to increase the current proposal of minimal binutils to 2.33). So, what I recommend you to do is: 1. Change the documentation patch [1] and update the powerpc sysdeps/powerpc/powerpc64/le/configure.ac to check 'as' version instead of 'objcopy'. 2. Add a configure check for the new TLS using PC-relative and set a new config.h flag (SUPPORT_PPC_TLS_PCREL). 3. Use it instead of __PCREL__ on internal testing. [1] https://sourceware.org/pipermail/libc-alpha/2021-January/121919.html > diff --git a/sysdeps/powerpc/powerpc64/tls-macros.h b/sysdeps/powerpc/powerpc64/tls-macros.h > index 79a0b2579c..a0e5c4a832 100644 > --- a/sysdeps/powerpc/powerpc64/tls-macros.h > +++ b/sysdeps/powerpc/powerpc64/tls-macros.h > @@ -9,20 +9,56 @@ > : "=b" (__result) ); \ > __result; \ > }) > -/* PowerPC64 Initial Exec TLS access. */ > -#define TLS_IE(x) \ > + > +/* PC-relative addressing is available when compiling with -mpcrel. > + The first releases of GCC 10 do support -mpcrel, but do not export > + __PCREL__. */ > +#if defined __PCREL__ > +/* PowerPC64 Initial Exec TLS access, PC-relative addressing. */ > +# define TLS_IE(x) \ > ({ int * __result; \ > - asm ("ld %0," #x "@got@tprel(2)\n\t" \ > - "add %0,%0," #x "@tls" \ > + asm ("pld %0," #x "@got@tprel@pcrel\n\t" \ > + "add %0,%0," #x "@tls@pcrel" \ > : "=r" (__result) ); \ > __result; \ > }) > > +/* PowerPC64 Local Dynamic TLS access, PC-relative addressing. */ > +# define TLS_LD(x) \ > + ({ int * __result; \ > + asm ("pla 3, " #x "@got@tlsld@pcrel\n\t" \ > + "bl __tls_get_addr@notoc(" #x "@tlsld)\n\t" \ > + "addis %0,3," #x "@dtprel@ha\n\t" \ > + "addi %0,%0," #x "@dtprel@l" \ > + : "=b" (__result) : \ > + : "3", __TLS_CALL_CLOBBERS); \ > + __result; \ > + }) > + > +/* PowerPC64 General Dynamic TLS access, PC-relative addressing. */ > +# define TLS_GD(x) \ > + ({ register int *__result __asm__ ("r3"); \ > + asm ("pla 3," #x "@got@tlsgd@pcrel\n\t" \ > + "bl __tls_get_addr@notoc(" #x "@tlsgd)" \ > + : "=r" (__result) : \ > + : __TLS_CALL_CLOBBERS); \ > + __result; \ > + }) > +#else > +/* PowerPC64 Initial Exec TLS access. */ > +# define TLS_IE(x) \ > + ({ int * __result; \ > + asm ("ld %0," #x "@got@tprel(2)\n\t" \ > + "add %0,%0," #x "@tls" \ > + : "=r" (__result) ); \ > + __result; \ > + }) > + > /* PowerPC64 Local Dynamic TLS access. */ > -#define TLS_LD(x) \ > +# define TLS_LD(x) \ > ({ int * __result; \ > asm ("addi 3,2," #x "@got@tlsld\n\t" \ > - "bl __tls_get_addr\n\t" \ > + "bl __tls_get_addr(" #x "@tlsld)\n\t" \ > "nop \n\t" \ > "addis %0,3," #x "@dtprel@ha\n\t" \ > "addi %0,%0," #x "@dtprel@l" \ > @@ -30,13 +66,15 @@ > : "3", __TLS_CALL_CLOBBERS); \ > __result; \ > }) > + > /* PowerPC64 General Dynamic TLS access. */ > -#define TLS_GD(x) \ > +# define TLS_GD(x) \ > ({ register int *__result __asm__ ("r3"); \ > asm ("addi 3,2," #x "@got@tlsgd\n\t" \ > - "bl __tls_get_addr\n\t" \ > + "bl __tls_get_addr(" #x "@tlsgd)\n\t" \ > "nop " \ > : "=r" (__result) : \ > : __TLS_CALL_CLOBBERS); \ > __result; \ > }) > +#endif >