Date: Mon, 16 Jun 2014 21:38:03 +0200 From: Michael Tuexen <tuexen@freebsd.org> To: Mark R V Murray <markm@FreeBSD.org> Cc: Hans Petter Selasky <hps@selasky.org>, svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r266083 - in head/sys/arm: arm include Message-ID: <44F7EEB4-46D1-49C7-A4CA-4EA5D41BDF31@freebsd.org> In-Reply-To: <6268E444-F6C7-4B8B-86B7-244A2BB3C4DE@FreeBSD.org> References: <201405141911.s4EJBFZZ097826@svn.freebsd.org> <537D0952.2040001@selasky.org> <7610C8E6-3F01-4317-BC1A-67645A162CD7@FreeBSD.org> <53871493.2010502@selasky.org> <EE7E19AA-BE18-4740-A636-4DA3023A5392@FreeBSD.org> <9412A358-EBCB-4A5A-B728-2A15C50FC217@fh-muenster.de> <D118F546-0F32-429F-86F2-69BEE0EC2D2F@FreeBSD.org> <CC36082E-1DFD-4576-9653-970F93A3699C@fh-muenster.de> <FD5DF228-1B2B-48F9-8445-54BF5959FEDA@FreeBSD.org> <9B438991-C970-46A7-8116-A490E02D7139@fh-muenster.de> <3841D090-5973-40B0-B61C-F15E8C1978C9@FreeBSD.org> <3664DBD3-7CEA-43E8-9757-E835BB21FE9E@freebsd.org> <5F36DFA5-C5B1-4E5D-88EE-9D60240B40FD@FreeBSD.org> <494BE7DA-26BC-43A7-8BC0-ECAE8A75E1EF@freebsd.org> <6268E444-F6C7-4B8B-86B7-244A2BB3C4DE@FreeBSD.org>
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On 16 Jun 2014, at 21:29, Mark R V Murray <markm@FreeBSD.org> wrote: >=20 > On 16 Jun 2014, at 20:25, Michael Tuexen <tuexen@freebsd.org> wrote: >>> Should print a whole lotta numbers, incrementing, unless you hit the = wraparound. >> Don't I need to compile a kernel with _PMC_USER_READ_WRITE_ being = defined, since >> without it a user process can't access the register. When running it = on a kernel >> not defining _PMC_USER_READ_WRITE_, I get a core with Illegal = instruction. >=20 > No. That only enables _write_ access. That=92s on ARMv7. What=92s in = ARMv6 may also work. Hmm, the documentation reads Access to the Cycle Counter Register in User mode depends on the V bit, = see c15, Secure User and Non-secure Access Validation Control Register. = The Cycle Counter Register is always accessible in Privileged modes. = Table 3.139 lists the results of attempted access for each mode. and the table shows read/write access for Secure Privileged and = Non-secure Privileged, but for User you need the V-bit. So in which modes are the user programs = running? One the normal kernel I get the Illegal Instruction error when I run the = program. Best regards Michael >=20 >> Let me build a kernel with the above define and retest. >=20 > Please try without it. >=20 > M > --=20 > Mark R V Murray >=20 >=20
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