From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Huth Subject: Re: [kvm-unit-tests PATCH v3 11/17] powerpc/ppc64: add hcall support and putchar Date: Mon, 15 Feb 2016 09:44:05 +0100 Message-ID: <56C18FD5.9070303@redhat.com> References: <1455380910-30604-1-git-send-email-drjones@redhat.com> <1455380910-30604-12-git-send-email-drjones@redhat.com> <20160214232954.GJ2732@voom.fritz.box> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="WWKPiwQJ8aqpt5IXKNsNjq2wSnOiSXIcB" Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, dgibson@redhat.com, agraf@suse.de, lvivier@redhat.com, pbonzini@redhat.com To: David Gibson , Andrew Jones Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35652 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752368AbcBOIoV (ORCPT ); Mon, 15 Feb 2016 03:44:21 -0500 In-Reply-To: <20160214232954.GJ2732@voom.fritz.box> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --WWKPiwQJ8aqpt5IXKNsNjq2wSnOiSXIcB Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 15.02.2016 00:29, David Gibson wrote: > On Sat, Feb 13, 2016 at 05:28:24PM +0100, Andrew Jones wrote: >> Add broken sc1 detection and patching and an hcall for putchar, >> to use in puts. That, along with a couple more lines in start to >> prepare for C code, and a branch to main(), gets us "hello world". >> Run with >> >> qemu-system-ppc64 -M pseries \ >> -bios powerpc/boot_rom.bin \ >> -display none -serial stdio \ >> -kernel powerpc/selftest.elf >> >> (We're still not relocating yet, that comes in a later patch. Thus, >> testing hello-world at this point requires a hacked QEMU and linking >> the unit test at QEMU's kernel load address.) >> >> Signed-off-by: Andrew Jones >> --- >> lib/powerpc/asm/hcall.h | 43 +++++++++++++++++++++++++++ >> lib/powerpc/hcall.c | 79 ++++++++++++++++++++++++++++++++++++++++= +++++++++ >> lib/powerpc/io.c | 15 ++++++++-- >> lib/ppc64/asm/hcall.h | 1 + >> powerpc/Makefile.common | 2 ++ >> powerpc/cstart64.S | 21 +++++++++++++ >> 6 files changed, 159 insertions(+), 2 deletions(-) >> create mode 100644 lib/powerpc/asm/hcall.h >> create mode 100644 lib/powerpc/hcall.c >> create mode 100644 lib/ppc64/asm/hcall.h >> >> diff --git a/lib/powerpc/asm/hcall.h b/lib/powerpc/asm/hcall.h >> new file mode 100644 >> index 0000000000000..75eac456c49eb >> --- /dev/null >> +++ b/lib/powerpc/asm/hcall.h >> @@ -0,0 +1,43 @@ >> +#ifndef _ASMPOWERPC_HCALL_H_ >> +#define _ASMPOWERPC_HCALL_H_ >> +/* >> + * Copyright (C) 2016, Red Hat Inc, Andrew Jones = >> + * >> + * This work is licensed under the terms of the GNU LGPL, version 2. >> + */ >> + >> +#define SC1 0x44000022 >> +#define SC1_REPLACEMENT 0x7c000268 >> + >> +#define H_SUCCESS 0 >> +#define H_HARDWARE -1 >> + >> +#define H_SET_DABR 0x28 >> +#define H_PUT_TERM_CHAR 0x58 >> + >> +#ifndef __ASSEMBLY__ >> +#include >> + >> +/* >> + * hcall_have_broken_sc1 checks if we're on a host with a broken sc1.= >> + * Returns true if we are. >> + */ >> +extern bool hcall_have_broken_sc1(void); >> + >> +/* >> + * hcall_patch_broken_sc1 patches hcall's sc1 instruction, if needed,= >> + * allowing all hypercalls built on it to work. >> + */ >> +extern void hcall_patch_broken_sc1(void); >> + >> +/* >> + * hcall is the hypercall wrapper function. unittests may do what >> + * they like, but the framework should make all hypercalls through >> + * here to ensure they use a working sc1 instruction, and properly >> + * handle clobbered registers. @nr is the hypercall number. >> + */ >> +extern unsigned long >> +hcall(unsigned long nr, unsigned long *in, unsigned long *out); >> + >> +#endif /* !__ASSEMBLY__ */ >> +#endif /* _ASMPOWERPC_HCALL_H_ */ >> diff --git a/lib/powerpc/hcall.c b/lib/powerpc/hcall.c >> new file mode 100644 >> index 0000000000000..4c42b18ef9901 >> --- /dev/null >> +++ b/lib/powerpc/hcall.c >> @@ -0,0 +1,79 @@ >> +/* >> + * Hypercall helpers >> + * >> + * broken_sc1 probing/patching inspired by SLOF, see >> + * SLOF:lib/libhvcall/brokensc1.c >> + * >> + * hcall() implementation inspired by Linux's epapr_hypercall, see >> + * arch/powerpc/include/asm/epapr_hcalls.h >> + * >> + * Copyright (C) 2016, Red Hat Inc, Andrew Jones = >> + * >> + * This work is licensed under the terms of the GNU LGPL, version 2. >> + */ >> +#include >> +#include >> + >> +static u32 sc1[]; >> + >> +bool hcall_have_broken_sc1(void) >> +{ >> + register unsigned long r3 asm("r3") =3D H_SET_DABR; >> + register unsigned long r4 asm("r4") =3D 0; >> + >> + asm volatile("sc 1" >> + : "=3Dr" (r3) >> + : "r" (r3), "r" (r4) >> + : "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"); >> + >> + return !(r3 =3D=3D H_SUCCESS || r3 =3D=3D (unsigned long)H_HARDWARE)= ; >=20 > It might be safer to explicitly check for H_PRIVILEGE, which is what > you'll get in the case of a broken sc 1 under nested virtualization. > That way you won't get false positives if H_SET_DABR ever gets any new > error codes it can return. Right - actually, H_SET_DABR already might return H_RESERVED_DABR now if the host does not support the DABRX register. 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