Hi Dave, Thank you for your reply.
> Your fix looks correct and seems to work. For stylistic reasons, I may > write it like this instead, but the effect should be the same: > > header->max_vl = sve_max_vl; > if (WARN_ON(!sve_vl_valid(sve_max_vl)) > header->max_vl = header->vl; It is better than my fix. Please, apply it at next version. Best regards, Takayuki Okamoto > -----Original Message----- > From: linux-arm-kernel > [mailto:linux-arm-kernel-boun...@lists.infradead.org] On Behalf Of Dave > Martin > Sent: Thursday, September 7, 2017 3:17 AM > To: Okamoto, Takayuki <tokam...@jp.fujitsu.com> > Cc: linux-a...@vger.kernel.org; libc-al...@sourceware.org; Ard > Biesheuvel <ard.biesheu...@linaro.org>; Szabolcs Nagy > <szabolcs.n...@arm.com>; g...@sourceware.org; Yao Qi <yao...@arm.com>; > Alan Hayward <alan.hayw...@arm.com>; Will Deacon <will.dea...@arm.com>; > Oleg Nesterov <o...@redhat.com>; Richard Sandiford > <richard.sandif...@arm.com>; Alexander Viro <v...@zeniv.linux.org.uk>; > Catalin Marinas <catalin.mari...@arm.com>; Alex Bennée > <alex.ben...@linaro.org>; kvmarm@lists.cs.columbia.edu; > linux-arm-ker...@lists.infradead.org > Subject: Re: [PATCH v2 19/28] arm64/sve: ptrace and ELF coredump support > > On Wed, Sep 06, 2017 at 04:21:50PM +0000, Okamoto, Takayuki wrote: > > Hi Dave, > > > > I am an engineer of the postK computer from Fujitsu. > > > > When I tried to read "max_vl" by ptrace with this patch on our local SVE > > simulator, it was read as zero. > > I think the cause of this incident is that "max_vl" is set as "header->vl" > > only on warning case in sve_init_header_from_task(). > > "max_vl" should be set up also on normal case, like the following patch. > > > > > > --- a/arch/arm64/kernel/ptrace.c > > +++ b/arch/arm64/kernel/ptrace.c > > @@ -755,6 +755,8 @@ static void sve_init_header_from_task(struct > user_sve_header *header, > > > > if (WARN_ON(!sve_vl_valid(sve_max_vl))) > > header->max_vl = header->vl; > > + else > > + header->max_vl = sve_max_vl; > > > > header->size = SVE_PT_SIZE(vq, header->flags); > > header->max_size = > SVE_PT_SIZE(sve_vq_from_vl(header->max_vl), > > Hi, thanks for reporting this. > > It looks like a refactoring mistake I made while removing BUG_ON()s, > which I missed in my testing. > > Your fix looks correct and seems to work. For stylistic reasons, I may > write it like this instead, but the effect should be the same: > > header->max_vl = sve_max_vl; > if (WARN_ON(!sve_vl_valid(sve_max_vl)) > header->max_vl = header->vl; > > Cheers > ---Dave > > > > > > > Best regards, > > Takayuki Okamoto > > > > -----Original Message----- > > From: gdb-ow...@sourceware.org [mailto:gdb-ow...@sourceware.org] On > Behalf Of Dave Martin > > Sent: Friday, September 1, 2017 2:01 AM > > To: linux-arm-ker...@lists.infradead.org > > Cc: Catalin Marinas <catalin.mari...@arm.com>; Will Deacon > <will.dea...@arm.com>; Ard Biesheuvel <ard.biesheu...@linaro.org>; Alex > Bennée <alex.ben...@linaro.org>; Szabolcs Nagy <szabolcs.n...@arm.com>; > Richard Sandiford <richard.sandif...@arm.com>; > kvmarm@lists.cs.columbia.edu; libc-al...@sourceware.org; > linux-a...@vger.kernel.org; g...@sourceware.org; Alan Hayward > <alan.hayw...@arm.com>; Yao Qi <yao...@arm.com>; Oleg Nesterov > <o...@redhat.com>; Alexander Viro <v...@zeniv.linux.org.uk> > > Subject: [PATCH v2 19/28] arm64/sve: ptrace and ELF coredump support > > > > [...] > > > @@ -702,6 +737,210 @@ static int system_call_set(struct task_struct > *target, > > return ret; > > } > > > > +#ifdef CONFIG_ARM64_SVE > > + > > +static void sve_init_header_from_task(struct user_sve_header *header, > > + struct task_struct *target) > > +{ > > + unsigned int vq; > > + > > + memset(header, 0, sizeof(*header)); > > + > > + header->flags = test_tsk_thread_flag(target, TIF_SVE) ? > > + SVE_PT_REGS_SVE : SVE_PT_REGS_FPSIMD; > > + if (test_tsk_thread_flag(target, TIF_SVE_VL_INHERIT)) > > + header->flags |= SVE_PT_VL_INHERIT; > > + > > + header->vl = target->thread.sve_vl; > > + vq = sve_vq_from_vl(header->vl); > > + > > + if (WARN_ON(!sve_vl_valid(sve_max_vl))) > > + header->max_vl = header->vl; > > + > > + header->size = SVE_PT_SIZE(vq, header->flags); > > + header->max_size = SVE_PT_SIZE(sve_vq_from_vl(header->max_vl), > > + SVE_PT_REGS_SVE); > > +} > > [...] > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
