Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933427AbeAJCE4 (ORCPT + 1 other); Tue, 9 Jan 2018 21:04:56 -0500 Received: from mail-qt0-f195.google.com ([209.85.216.195]:42921 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933239AbeAJCEx (ORCPT ); Tue, 9 Jan 2018 21:04:53 -0500 X-Google-Smtp-Source: ACJfBotWYJwqsCpPSPGE/FHNE9YU3f0ILdygMNMCxFEFXbIQF7laBg40zDXslUqXetd4D9qEmrABZg== Subject: Re: [PATCH 04/18] arm: implement nospec_ptr() To: Dan Williams , linux-kernel@vger.kernel.org, Mark Rutland Cc: linux-arch@vger.kernel.org, peterz@infradead.org, netdev@vger.kernel.org, gregkh@linuxfoundation.org, tglx@linutronix.de, torvalds@linux-foundation.org, alan@linux.intel.com, Justin Forbes References: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> <151520101463.32271.9320376934909324865.stgit@dwillia2-desk3.amr.corp.intel.com> From: Laura Abbott Message-ID: <32f6f9de-1f8f-f459-d9e4-c9a7044cf8af@redhat.com> Date: Tue, 9 Jan 2018 18:04:49 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <151520101463.32271.9320376934909324865.stgit@dwillia2-desk3.amr.corp.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On 01/05/2018 05:10 PM, Dan Williams wrote: > From: Mark Rutland > > This patch implements nospec_ptr() for arm, following the recommended > architectural sequences for the arm and thumb instruction sets. > Fedora picked up the series and it fails on arm: In file included from ./include/linux/compiler.h:242:0, from ./include/uapi/linux/swab.h:6, from ./include/linux/swab.h:5, from ./arch/arm/include/asm/opcodes.h:89, from ./arch/arm/include/asm/bug.h:7, from ./include/linux/bug.h:5, from ./include/linux/mmdebug.h:5, from ./include/linux/gfp.h:5, from ./include/linux/slab.h:15, from kernel/fork.c:14: ./include/linux/fdtable.h: In function '__fcheck_files': ./arch/arm/include/asm/barrier.h:112:41: error: expected declaration specifiers or '...' before numeric constant __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ ^ ./arch/arm/include/asm/barrier.h:68:32: note: in definition of macro '__load_no_speculate_n' (typeof(*ptr)(unsigned long)(failval)); \ ^~~~~~~ ./arch/arm/include/asm/barrier.h:112:2: note: in expansion of macro '__load_no_speculate' __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ ^~~~~~~~~~~~~~~~~~~ ./include/asm-generic/barrier.h:122:2: note: in expansion of macro 'nospec_ptr' nospec_ptr(__arr + __idx, __arr, __arr + __sz); \ ^~~~~~~~~~ ./include/linux/fdtable.h:86:13: note: in expansion of macro 'nospec_array_ptr' if ((fdp = nospec_array_ptr(fdt->fd, fd, fdt->max_fds))) ^~~~~~~~~~~~~~~~ ./arch/arm/include/asm/barrier.h:112:41: error: expected declaration specifiers or '...' before numeric constant __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ ^ ./arch/arm/include/asm/barrier.h:68:32: note: in definition of macro '__load_no_speculate_n' (typeof(*ptr)(unsigned long)(failval)); \ ^~~~~~~ ./arch/arm/include/asm/barrier.h:112:2: note: in expansion of macro '__load_no_speculate' __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ ^~~~~~~~~~~~~~~~~~~ ./include/asm-generic/barrier.h:122:2: note: in expansion of macro 'nospec_ptr' nospec_ptr(__arr + __idx, __arr, __arr + __sz); \ ^~~~~~~~~~ ./include/linux/fdtable.h:86:13: note: in expansion of macro 'nospec_array_ptr' if ((fdp = nospec_array_ptr(fdt->fd, fd, fdt->max_fds))) ^~~~~~~~~~~~~~~~ ./arch/arm/include/asm/barrier.h:112:41: error: expected declaration specifiers or '...' before numeric constant __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ ^ ./arch/arm/include/asm/barrier.h:68:32: note: in definition of macro '__load_no_speculate_n' (typeof(*ptr)(unsigned long)(failval)); \ ^~~~~~~ ./arch/arm/include/asm/barrier.h:112:2: note: in expansion of macro '__load_no_speculate' __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ ^~~~~~~~~~~~~~~~~~~ ./include/asm-generic/barrier.h:122:2: note: in expansion of macro 'nospec_ptr' nospec_ptr(__arr + __idx, __arr, __arr + __sz); \ ^~~~~~~~~~ ./include/linux/fdtable.h:86:13: note: in expansion of macro 'nospec_array_ptr' if ((fdp = nospec_array_ptr(fdt->fd, fd, fdt->max_fds))) I can't puzzle out what exactly is the problem here, except that it really does not seem to like that failval. Does the arm compiler not like doing the typeof with the __arr + __idx? Thanks, Laura > Signed-off-by: Mark Rutland > Signed-off-by: Dan Williams > --- > arch/arm/include/asm/barrier.h | 75 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 75 insertions(+) > > diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h > index 40f5c410fd8c..6384c90e4b72 100644 > --- a/arch/arm/include/asm/barrier.h > +++ b/arch/arm/include/asm/barrier.h > @@ -37,6 +37,81 @@ > #define dmb(x) __asm__ __volatile__ ("" : : : "memory") > #endif > > +#ifdef CONFIG_THUMB2_KERNEL > +#define __load_no_speculate_n(ptr, lo, hi, failval, cmpptr, sz) \ > +({ \ > + typeof(*ptr) __nln_val; \ > + typeof(*ptr) __failval = \ > + (typeof(*ptr)(unsigned long)(failval)); \ > + \ > + asm volatile ( \ > + " cmp %[c], %[l]\n" \ > + " it hs\n" \ > + " cmphs %[h], %[c]\n" \ > + " blo 1f\n" \ > + " ld" #sz " %[v], %[p]\n" \ > + "1: it lo\n" \ > + " movlo %[v], %[f]\n" \ > + " .inst 0xf3af8014 @ CSDB\n" \ > + : [v] "=&r" (__nln_val) \ > + : [p] "m" (*(ptr)), [l] "r" (lo), [h] "r" (hi), \ > + [f] "r" (__failval), [c] "r" (cmpptr) \ > + : "cc"); \ > + \ > + __nln_val; \ > +}) > +#else > +#define __load_no_speculate_n(ptr, lo, hi, failval, cmpptr, sz) \ > +({ \ > + typeof(*ptr) __nln_val; \ > + typeof(*ptr) __failval = \ > + (typeof(*ptr)(unsigned long)(failval)); \ > + \ > + asm volatile ( \ > + " cmp %[c], %[l]\n" \ > + " cmphs %[h], %[c]\n" \ > + " ldr" #sz "hi %[v], %[p]\n" \ > + " movls %[v], %[f]\n" \ > + " .inst 0xe320f014 @ CSDB\n" \ > + : [v] "=&r" (__nln_val) \ > + : [p] "m" (*(ptr)), [l] "r" (lo), [h] "r" (hi), \ > + [f] "r" (__failval), [c] "r" (cmpptr) \ > + : "cc"); \ > + \ > + __nln_val; \ > +}) > +#endif > + > +#define __load_no_speculate(ptr, lo, hi, failval, cmpptr) \ > +({ \ > + typeof(*(ptr)) __nl_val; \ > + \ > + switch (sizeof(__nl_val)) { \ > + case 1: \ > + __nl_val = __load_no_speculate_n(ptr, lo, hi, failval, \ > + cmpptr, b); \ > + break; \ > + case 2: \ > + __nl_val = __load_no_speculate_n(ptr, lo, hi, failval, \ > + cmpptr, h); \ > + break; \ > + case 4: \ > + __nl_val = __load_no_speculate_n(ptr, lo, hi, failval, \ > + cmpptr, ); \ > + break; \ > + default: \ > + BUILD_BUG(); \ > + } \ > + \ > + __nl_val; \ > +}) > + > +#define nospec_ptr(ptr, lo, hi) \ > +({ \ > + typeof(ptr) __np_ptr = (ptr); \ > + __load_no_speculate(&__np_ptr, lo, hi, 0, __np_ptr); \ > +}) > + > #ifdef CONFIG_ARM_HEAVY_MB > extern void (*soc_mb)(void); > extern void arm_heavy_mb(void); >