From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753986AbeCYSKq (ORCPT ); Sun, 25 Mar 2018 14:10:46 -0400 Received: from mail.kmu-office.ch ([178.209.48.109]:54219 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753868AbeCYSKF (ORCPT ); Sun, 25 Mar 2018 14:10:05 -0400 From: Stefan Agner To: linux@armlinux.org.uk, ard.biesheuvel@linaro.org, arnd@arndb.de Cc: robin.murphy@arm.com, nicolas.pitre@linaro.org, marc.zyngier@arm.com, behanw@converseincode.com, keescook@chromium.org, Bernhard.Rosenkranzer@linaro.org, mka@chromium.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Stefan Agner , Dmitry Osipenko , Stephen Warren , Thierry Reding Subject: [PATCH v2 3/6] ARM: trusted_foundations: do not use naked function Date: Sun, 25 Mar 2018 20:09:56 +0200 Message-Id: <20180325180959.28008-4-stefan@agner.ch> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180325180959.28008-1-stefan@agner.ch> References: <20180325180959.28008-1-stefan@agner.ch> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As documented in GCC naked functions should only use Basic asm syntax. The Extended asm or mixture of Basic asm and "C" code is not guaranteed. Currently this works because it was hard coded to follow and check GCC behavior for arguments and register placement. Furthermore with clang using parameters in Extended asm in a naked function is not supported: arch/arm/firmware/trusted_foundations.c:47:10: error: parameter references not allowed in naked functions : "r" (type), "r" (arg1), "r" (arg2) ^ Use a regular function to be more portable. This aligns also with the other smc call implementations e.g. in qcom_scm-32.c and bcm_kona_smc.c. Cc: Dmitry Osipenko Cc: Stephen Warren Cc: Thierry Reding Signed-off-by: Stefan Agner --- Changes in v2: - Keep stmfd/ldmfd to avoid potential ABI issues arch/arm/firmware/trusted_foundations.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/arch/arm/firmware/trusted_foundations.c b/arch/arm/firmware/trusted_foundations.c index 3fb1b5a1dce9..689e6565abfc 100644 --- a/arch/arm/firmware/trusted_foundations.c +++ b/arch/arm/firmware/trusted_foundations.c @@ -31,21 +31,25 @@ static unsigned long cpu_boot_addr; -static void __naked tf_generic_smc(u32 type, u32 arg1, u32 arg2) +static void tf_generic_smc(u32 type, u32 arg1, u32 arg2) { + register u32 r0 asm("r0") = type; + register u32 r1 asm("r1") = arg1; + register u32 r2 asm("r2") = arg2; + asm volatile( ".arch_extension sec\n\t" - "stmfd sp!, {r4 - r11, lr}\n\t" + "stmfd sp!, {r4 - r11}\n\t" __asmeq("%0", "r0") __asmeq("%1", "r1") __asmeq("%2", "r2") "mov r3, #0\n\t" "mov r4, #0\n\t" "smc #0\n\t" - "ldmfd sp!, {r4 - r11, pc}" + "ldmfd sp!, {r4 - r11}\n\t" : - : "r" (type), "r" (arg1), "r" (arg2) - : "memory"); + : "r" (r0), "r" (r1), "r" (r2) + : "memory", "r3", "r12", "lr"); } static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr) -- 2.16.2 From mboxrd@z Thu Jan 1 00:00:00 1970 From: stefan@agner.ch (Stefan Agner) Date: Sun, 25 Mar 2018 20:09:56 +0200 Subject: [PATCH v2 3/6] ARM: trusted_foundations: do not use naked function In-Reply-To: <20180325180959.28008-1-stefan@agner.ch> References: <20180325180959.28008-1-stefan@agner.ch> Message-ID: <20180325180959.28008-4-stefan@agner.ch> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org As documented in GCC naked functions should only use Basic asm syntax. The Extended asm or mixture of Basic asm and "C" code is not guaranteed. Currently this works because it was hard coded to follow and check GCC behavior for arguments and register placement. Furthermore with clang using parameters in Extended asm in a naked function is not supported: arch/arm/firmware/trusted_foundations.c:47:10: error: parameter references not allowed in naked functions : "r" (type), "r" (arg1), "r" (arg2) ^ Use a regular function to be more portable. This aligns also with the other smc call implementations e.g. in qcom_scm-32.c and bcm_kona_smc.c. Cc: Dmitry Osipenko Cc: Stephen Warren Cc: Thierry Reding Signed-off-by: Stefan Agner --- Changes in v2: - Keep stmfd/ldmfd to avoid potential ABI issues arch/arm/firmware/trusted_foundations.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/arch/arm/firmware/trusted_foundations.c b/arch/arm/firmware/trusted_foundations.c index 3fb1b5a1dce9..689e6565abfc 100644 --- a/arch/arm/firmware/trusted_foundations.c +++ b/arch/arm/firmware/trusted_foundations.c @@ -31,21 +31,25 @@ static unsigned long cpu_boot_addr; -static void __naked tf_generic_smc(u32 type, u32 arg1, u32 arg2) +static void tf_generic_smc(u32 type, u32 arg1, u32 arg2) { + register u32 r0 asm("r0") = type; + register u32 r1 asm("r1") = arg1; + register u32 r2 asm("r2") = arg2; + asm volatile( ".arch_extension sec\n\t" - "stmfd sp!, {r4 - r11, lr}\n\t" + "stmfd sp!, {r4 - r11}\n\t" __asmeq("%0", "r0") __asmeq("%1", "r1") __asmeq("%2", "r2") "mov r3, #0\n\t" "mov r4, #0\n\t" "smc #0\n\t" - "ldmfd sp!, {r4 - r11, pc}" + "ldmfd sp!, {r4 - r11}\n\t" : - : "r" (type), "r" (arg1), "r" (arg2) - : "memory"); + : "r" (r0), "r" (r1), "r" (r2) + : "memory", "r3", "r12", "lr"); } static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr) -- 2.16.2