From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 45031 invoked by alias); 8 Feb 2019 11:38:32 -0000 Mailing-List: contact newlib-cvs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: newlib-cvs-owner@sourceware.org Received: (qmail 44923 invoked by uid 9078); 8 Feb 2019 11:38:31 -0000 Date: Fri, 08 Feb 2019 11:38:00 -0000 Message-ID: <20190208113831.44922.qmail@sourceware.org> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Corinna Vinschen To: newlib-cvs@sourceware.org Subject: [newlib-cygwin] AArch32: Add support for HLT to Mixed Mode models X-Act-Checkin: newlib-cygwin X-Git-Author: Tamar Christina X-Git-Refname: refs/heads/master X-Git-Oldrev: 3956ddd9bf28c518e73faf74c812379de02c3881 X-Git-Newrev: 6d6a623e7d8eb9e521bdbd73a7eafdd482678cea X-SW-Source: 2019-q1/txt/msg00024.txt.bz2 https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=6d6a623e7d8eb9e521bdbd73a7eafdd482678cea commit 6d6a623e7d8eb9e521bdbd73a7eafdd482678cea Author: Tamar Christina Date: Wed Feb 6 11:27:12 2019 +0000 AArch32: Add support for HLT to Mixed Mode models The Semihosting v2 protocol requires us to output the Armv8-a HLT instruction when in mixed mode (SEMIHOST_V2_MIXED_MODE), however it also requires this to be done for Armv7-a and earlier architectures. The HLT instruction is defined in the undefined encoding space for older architectures but simulators such as QEMU already trap on it [1] for all architectures and is a requirement for semihosting v2 [2]. Unfortunately the GAS restricts the use of HLT to Armv8-a which requires us to use the instruction encodings we want directly in crt0. This patch does this, I have not updated newlib/libc/* as that is quite out of date already. A proper sync is needed in order to get things back in sync. A different patch for this would be best. [1] https://github.com/qemu/qemu/commit/19a6e31c9d2701ef648b70ddcfc3bf64cec8c37e [2] https://developer.arm.com/docs/100863/latest/the-semihosting-interface Diff: --- libgloss/arm/crt0.S | 6 +++--- libgloss/arm/swi.h | 14 ++++++++++---- 2 files changed, 13 insertions(+), 7 deletions(-) diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S index 48f3d6b..c708f63 100644 --- a/libgloss/arm/crt0.S +++ b/libgloss/arm/crt0.S @@ -116,10 +116,10 @@ bkpt AngelSWI #elif defined(__thumb2__) /* We are in thumb mode for startup on armv7 architectures. */ - AngelSWIAsm AngelSWI + AngelSWIAsm (AngelSWI) #else /* We are always in ARM mode for startup on pre armv7 archs. */ - AngelSWIAsm AngelSWI_ARM + AngelSWIAsm (AngelSWI_ARM) #endif ldr r0, .LC0 /* point at values read */ @@ -297,7 +297,7 @@ __change_mode: #else movs r0, #AngelSWI_Reason_GetCmdLine ldr r1, .LC30 /* Space for command line */ - AngelSWIAsm AngelSWI + AngelSWIAsm (AngelSWI) ldr r1, .LC30 ldr r1, [r1] #endif diff --git a/libgloss/arm/swi.h b/libgloss/arm/swi.h index 67eb36b..8f50ee7 100644 --- a/libgloss/arm/swi.h +++ b/libgloss/arm/swi.h @@ -31,9 +31,9 @@ /* Now the SWI numbers and reason codes for RDI (Angel) monitors. */ #if defined (SEMIHOST_V2) && defined (SEMIHOST_V2_MIXED_MODE) - #define AngelSWI_ARM 0xF000 /* HLT A32. */ + #define AngelSWI_ARM 0xE10F0070 /* HLT #0xF000 A32. */ #ifdef __thumb__ - #define AngelSWI 0x3C /* HLT T32. */ + #define AngelSWI 0xBABC /* HLT #0x3c T32. */ #else /* __thumb__. */ #define AngelSWI AngelSWI_ARM #endif /* __thumb__. */ @@ -49,10 +49,16 @@ /* For thumb only architectures use the BKPT instruction instead of SWI. */ #ifdef THUMB_VXM #define AngelSWIInsn "bkpt" - #define AngelSWIAsm bkpt + #define AngelSWIAsm(IMM) bkpt IMM +#elif defined (SEMIHOST_V2) && defined (SEMIHOST_V2_MIXED_MODE) + /* This is actually encoding the HLT instruction, however we don't have + support for this in older assemblers. So we have to encode the + instruction manually. */ + #define AngelSWIInsn ".inst" + #define AngelSWIAsm(IMM) .inst IMM #else #define AngelSWIInsn "swi" - #define AngelSWIAsm swi + #define AngelSWIAsm(IMM) swi IMM #endif /* The reason codes: */