From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B987C2BA03 for ; Wed, 12 May 2021 16:37:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55CBC611BE for ; Wed, 12 May 2021 16:37:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237619AbhELQiI (ORCPT ); Wed, 12 May 2021 12:38:08 -0400 Received: from foss.arm.com ([217.140.110.172]:43614 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237920AbhELQOv (ORCPT ); Wed, 12 May 2021 12:14:51 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E54DB1FB; Wed, 12 May 2021 09:13:42 -0700 (PDT) Received: from [192.168.0.110] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2A8083F719; Wed, 12 May 2021 09:13:42 -0700 (PDT) Subject: Re: [PATCH kvm-unit-tests v3 8/8] arm/arm64: psci: Don't assume method is hvc To: Andrew Jones , kvm@vger.kernel.org Cc: nikos.nikoleris@arm.com, andre.przywara@arm.com, eric.auger@redhat.com References: <20210429164130.405198-1-drjones@redhat.com> <20210429164130.405198-9-drjones@redhat.com> From: Alexandru Elisei Message-ID: <3dd4b8f6-612d-e0c0-f5b5-d8a380213a1d@arm.com> Date: Wed, 12 May 2021 17:14:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210429164130.405198-9-drjones@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Drew, On 4/29/21 5:41 PM, Andrew Jones wrote: > The method can be smc in addition to hvc, and it will be when running > on bare metal. Additionally, we move the invocations to assembly so > we don't have to rely on compiler assumptions. We also fix the > prototype of psci_invoke. It should return long, not int, and > function_id should be an unsigned int, not an unsigned long. Sorry to harp on this again, but to be honest, it's still not clear to me why the psci_invoke_{hvc,smc} functions return a long int. If we only expect the PSCI functions to return error codes, then the PSCI spec says these are 32-bit signed integers. If we want to support PSCI functions returning other values, like PSCI_STAT_{RESIDENCY,COUNT}, then the invoke functions should return an unsigned value. The only case we're supporting is the error return for the SMC calling convention (which says that error codes are 32/64bit signed integers). Since the commit specifically mentions this change, I think some explanation why this width was chosen would be appropriate. Unless it's painfully obvious and I'm just not seeing it, which is a possibility. Other than that, the patch looks good. I'll some tests to make sure everything is in order. Thanks, Alex > > Signed-off-by: Andrew Jones > --- > arm/cstart.S | 22 ++++++++++++++++++++++ > arm/cstart64.S | 22 ++++++++++++++++++++++ > arm/selftest.c | 34 +++++++--------------------------- > lib/arm/asm/psci.h | 10 ++++++++-- > lib/arm/psci.c | 35 +++++++++++++++++++++++++++-------- > lib/arm/setup.c | 2 ++ > 6 files changed, 88 insertions(+), 37 deletions(-) > > diff --git a/arm/cstart.S b/arm/cstart.S > index 446966de350d..2401d92cdadc 100644 > --- a/arm/cstart.S > +++ b/arm/cstart.S > @@ -95,6 +95,28 @@ start: > > .text > > +/* > + * psci_invoke_hvc / psci_invoke_smc > + * > + * Inputs: > + * r0 -- function_id > + * r1 -- arg0 > + * r2 -- arg1 > + * r3 -- arg2 > + * > + * Outputs: > + * r0 -- return code > + */ > +.globl psci_invoke_hvc > +psci_invoke_hvc: > + hvc #0 > + mov pc, lr > + > +.globl psci_invoke_smc > +psci_invoke_smc: > + smc #0 > + mov pc, lr > + > enable_vfp: > /* Enable full access to CP10 and CP11: */ > mov r0, #(3 << 22 | 3 << 20) > diff --git a/arm/cstart64.S b/arm/cstart64.S > index 42ba3a3ca249..e4ab7d06251e 100644 > --- a/arm/cstart64.S > +++ b/arm/cstart64.S > @@ -109,6 +109,28 @@ start: > > .text > > +/* > + * psci_invoke_hvc / psci_invoke_smc > + * > + * Inputs: > + * w0 -- function_id > + * x1 -- arg0 > + * x2 -- arg1 > + * x3 -- arg2 > + * > + * Outputs: > + * x0 -- return code > + */ > +.globl psci_invoke_hvc > +psci_invoke_hvc: > + hvc #0 > + ret > + > +.globl psci_invoke_smc > +psci_invoke_smc: > + smc #0 > + ret > + > get_mmu_off: > adrp x0, auxinfo > ldr x0, [x0, :lo12:auxinfo + 8] > diff --git a/arm/selftest.c b/arm/selftest.c > index 4495b161cdd5..9f459ed3d571 100644 > --- a/arm/selftest.c > +++ b/arm/selftest.c > @@ -400,33 +400,13 @@ static void check_vectors(void *arg __unused) > exit(report_summary()); > } > > -static bool psci_check(void) > +static void psci_print(void) > { > - const struct fdt_property *method; > - int node, len, ver; > - > - node = fdt_node_offset_by_compatible(dt_fdt(), -1, "arm,psci-0.2"); > - if (node < 0) { > - printf("PSCI v0.2 compatibility required\n"); > - return false; > - } > - > - method = fdt_get_property(dt_fdt(), node, "method", &len); > - if (method == NULL) { > - printf("bad psci device tree node\n"); > - return false; > - } > - > - if (len < 4 || strcmp(method->data, "hvc") != 0) { > - printf("psci method must be hvc\n"); > - return false; > - } > - > - ver = psci_invoke(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0); > - printf("PSCI version %d.%d\n", PSCI_VERSION_MAJOR(ver), > - PSCI_VERSION_MINOR(ver)); > - > - return true; > + int ver = psci_invoke(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0); > + report_info("PSCI version: %d.%d", PSCI_VERSION_MAJOR(ver), > + PSCI_VERSION_MINOR(ver)); > + report_info("PSCI method: %s", psci_invoke == psci_invoke_hvc ? > + "hvc" : "smc"); > } > > static void cpu_report(void *data __unused) > @@ -465,7 +445,7 @@ int main(int argc, char **argv) > > } else if (strcmp(argv[1], "smp") == 0) { > > - report(psci_check(), "PSCI version"); > + psci_print(); > on_cpus(cpu_report, NULL); > while (!cpumask_full(&ready)) > cpu_relax(); > diff --git a/lib/arm/asm/psci.h b/lib/arm/asm/psci.h > index 7b956bf5987d..f87fca0422cc 100644 > --- a/lib/arm/asm/psci.h > +++ b/lib/arm/asm/psci.h > @@ -3,8 +3,14 @@ > #include > #include > > -extern int psci_invoke(unsigned long function_id, unsigned long arg0, > - unsigned long arg1, unsigned long arg2); > +typedef long (*psci_invoke_fn)(unsigned int function_id, unsigned long arg0, > + unsigned long arg1, unsigned long arg2); > +extern psci_invoke_fn psci_invoke; > +extern long psci_invoke_hvc(unsigned int function_id, unsigned long arg0, > + unsigned long arg1, unsigned long arg2); > +extern long psci_invoke_smc(unsigned int function_id, unsigned long arg0, > + unsigned long arg1, unsigned long arg2); > +extern void psci_set_conduit(void); > extern int psci_cpu_on(unsigned long cpuid, unsigned long entry_point); > extern void psci_system_reset(void); > extern int cpu_psci_cpu_boot(unsigned int cpu); > diff --git a/lib/arm/psci.c b/lib/arm/psci.c > index 936c83948b6a..3053b3041c28 100644 > --- a/lib/arm/psci.c > +++ b/lib/arm/psci.c > @@ -6,22 +6,21 @@ > * > * This work is licensed under the terms of the GNU LGPL, version 2. > */ > +#include > #include > #include > #include > #include > > -__attribute__((noinline)) > -int psci_invoke(unsigned long function_id, unsigned long arg0, > - unsigned long arg1, unsigned long arg2) > +static long psci_invoke_none(unsigned int function_id, unsigned long arg0, > + unsigned long arg1, unsigned long arg2) > { > - asm volatile( > - "hvc #0" > - : "+r" (function_id) > - : "r" (arg0), "r" (arg1), "r" (arg2)); > - return function_id; > + printf("No PSCI method configured! Can't invoke...\n"); > + return PSCI_RET_NOT_PRESENT; > } > > +psci_invoke_fn psci_invoke = psci_invoke_none; > + > int psci_cpu_on(unsigned long cpuid, unsigned long entry_point) > { > #ifdef __arm__ > @@ -56,3 +55,23 @@ void psci_system_off(void) > int err = psci_invoke(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0); > printf("CPU%d unable to do system off (error = %d)\n", smp_processor_id(), err); > } > + > +void psci_set_conduit(void) > +{ > + const void *fdt = dt_fdt(); > + const struct fdt_property *method; > + int node, len; > + > + node = fdt_node_offset_by_compatible(fdt, -1, "arm,psci-0.2"); > + assert_msg(node >= 0, "PSCI v0.2 compatibility required"); > + > + method = fdt_get_property(fdt, node, "method", &len); > + assert(method != NULL && len == 4); > + > + if (strcmp(method->data, "hvc") == 0) > + psci_invoke = psci_invoke_hvc; > + else if (strcmp(method->data, "smc") == 0) > + psci_invoke = psci_invoke_smc; > + else > + assert_msg(false, "Unknown PSCI conduit: %s", method->data); > +} > diff --git a/lib/arm/setup.c b/lib/arm/setup.c > index 86f054304baf..bcdf0d78c2e2 100644 > --- a/lib/arm/setup.c > +++ b/lib/arm/setup.c > @@ -25,6 +25,7 @@ > #include > #include > #include > +#include > > #include "io.h" > > @@ -266,6 +267,7 @@ void setup(const void *fdt, phys_addr_t freemem_start) > mem_regions_add_assumed(); > mem_init(PAGE_ALIGN((unsigned long)freemem)); > > + psci_set_conduit(); > cpu_init(); > > /* cpu_init must be called before thread_info_init */