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[195.5.145.226]) by smtp.gmail.com with ESMTPSA id u17sm4552307lfq.69.2019.07.19.06.22.22 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 19 Jul 2019 06:22:22 -0700 (PDT) From: alfedotov@gmail.com To: Richard.Earnshaw@arm.com, newlib@sourceware.org Cc: Alexander Fedotov Subject: [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment. Date: Fri, 19 Jul 2019 08:22:17 -0500 Message-Id: <20190719132218.3108-1-alfedotov@gmail.com> From: Alexander Fedotov --- libgloss/arm/crt0.S | 137 +++++++++++++++++++------------------ newlib/libc/sys/arm/crt0.S | 20 +++--- 2 files changed, 80 insertions(+), 77 deletions(-) -- 2.17.1 diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S index c708f63d8..f21add8bc 100644 --- a/libgloss/arm/crt0.S +++ b/libgloss/arm/crt0.S @@ -68,8 +68,10 @@ #endif .endm +/******************************************************************************* +* Main library startup code. +*******************************************************************************/ .align 0 - FUNC_START _mainCRTStartup FUNC_START _start #if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) @@ -90,14 +92,14 @@ #endif #endif -/* Start by setting up a stack */ +/* Start by setting up a stack. */ #ifdef ARM_RDP_MONITOR - /* Issue Demon SWI to read stack info */ - swi SWI_GetEnv /* Returns command line in r0 */ - mov sp,r1 /* and the highest memory address in r1 */ + /* Issue Demon SWI to read stack info. */ + swi SWI_GetEnv /* Returns command line in r0. */ + mov sp,r1 /* and the highest memory address in r1. */ - /* stack limit is at end of data */ - /* allow slop for stack overflow handling and small frames */ + /* Stack limit is at end of data. */ + /* Allow slop for stack overflow handling and small frames. */ #ifdef THUMB1_ONLY ldr r0, .LC2 adds r0, #128 @@ -109,19 +111,19 @@ #endif #else #ifdef ARM_RDI_MONITOR - /* Issue Angel SWI to read stack info */ + /* Issue Angel SWI to read stack info. */ movs r0, #AngelSWI_Reason_HeapInfo - adr r1, .LC0 /* point at ptr to 4 words to receive data */ + adr r1, .LC0 /* Point at ptr to 4 words to receive data. */ #ifdef THUMB_VXM bkpt AngelSWI #elif defined(__thumb2__) - /* We are in thumb mode for startup on armv7 architectures. */ + /* We are in thumb mode for startup on armv7 architectures. */ AngelSWIAsm (AngelSWI) #else - /* We are always in ARM mode for startup on pre armv7 archs. */ + /* We are always in ARM mode for startup on pre armv7 archs. */ AngelSWIAsm (AngelSWI_ARM) #endif - ldr r0, .LC0 /* point at values read */ + ldr r0, .LC0 /* Point at values read. */ /* Set __heap_limit. */ ldr r1, [r0, #4] @@ -148,14 +150,15 @@ to skip setting sp/sl to 0 here. - Considering M-profile processors, We might want to initialize sp by the first entry of vector table and return 0 to SYS_HEAPINFO - semihosting call, which will be skipped here. */ + semihosting call, which will be skipped here. */ cmp r1, #0 beq .LC26 mov sp, r1 .LC26: cmp r2, #0 beq .LC27 - /* allow slop for stack overflow handling and small frames */ + + /* Allow slop for stack overflow handling and small frames. */ #ifdef THUMB1_ONLY adds r2, #128 adds r2, #128 @@ -163,9 +166,10 @@ #else add sl, r2, #256 #endif + .LC27: #else - /* Set up the stack pointer to a fixed value */ + /* Set up the stack pointer to a fixed value. */ /* Changes by toralf: - Allow linker script to provide stack via __stack symbol - see defintion of .Lstack @@ -175,7 +179,7 @@ Loosely based on init.s from ARM/Motorola example code. Note: Mode switch via CPSR is not allowed once in non-privileged mode, so we take care not to enter "User" to set up its sp, - and also skip most operations if already in that mode. */ + and also skip most operations if already in that mode. */ ldr r3, .Lstack cmp r3, #0 @@ -192,42 +196,42 @@ /* Note: This 'mov' is essential when starting in User, and ensures we always get *some* sp value for the initial mode, even if we have somehow missed it below (in which case it gets the same - value as FIQ - not ideal, but better than nothing.) */ + value as FIQ - not ideal, but better than nothing). */ mov sp, r3 #ifdef PREFER_THUMB /* XXX Fill in stack assignments for interrupt modes. */ #else mrs r2, CPSR - tst r2, #0x0F /* Test mode bits - in User of all are 0 */ - beq .LC23 /* "eq" means r2 AND #0x0F is 0 */ - msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled */ + tst r2, #0x0F /* Test mode bits - in User of all are 0. */ + beq .LC23 /* "eq" means r2 AND #0x0F is 0. */ + msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled. */ mov sp, r3 - sub sl, sp, #0x1000 /* This mode also has its own sl (see below) */ + sub sl, sp, #0x1000 /* This mode also has its own sl (see below). */ mov r3, sl - msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled */ + msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled. */ mov sp, r3 sub r3, r3, #0x1000 - msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled */ + msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled. */ mov sp, r3 sub r3, r3, #0x1000 - msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled */ + msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled. */ mov sp, r3 sub r3, r3, #0x2000 - msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled */ + msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled. */ mov sp, r3 - sub r3, r3, #0x8000 /* Min size 32k */ - bic r3, r3, #0x00FF /* Align with current 64k block */ + sub r3, r3, #0x8000 /* Min size 32k. */ + bic r3, r3, #0x00FF /* Align with current 64k block. */ bic r3, r3, #0xFF00 str r3, [r3, #-4] /* Move value into user mode sp without */ - ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm */ + ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm. */ orr r2, r2, #0xC0 /* Back to original mode, presumably SVC, */ - msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1 */ + msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1. */ #endif .LC23: /* Setup a default stack-limit in-case the code has been @@ -243,24 +247,24 @@ subs r2, r3, r2 mov sl, r2 #else - sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl */ + sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl. */ #endif #endif #endif /* Zero the memory in the .bss section. */ - movs a2, #0 /* Second arg: fill value */ - mov fp, a2 /* Null frame pointer */ - mov r7, a2 /* Null frame pointer for Thumb */ + movs a2, #0 /* Second arg: fill value. */ + mov fp, a2 /* Null frame pointer. */ + mov r7, a2 /* Null frame pointer for Thumb. */ - ldr a1, .LC1 /* First arg: start of memory block */ + ldr a1, .LC1 /* First arg: start of memory block. */ ldr a3, .LC2 - subs a3, a3, a1 /* Third arg: length of block */ + subs a3, a3, a1 /* Third arg: length of block. */ #if __thumb__ && !defined(PREFER_THUMB) - /* Enter Thumb mode.... */ - add a4, pc, #1 /* Get the address of the Thumb block */ - bx a4 /* Go there and start Thumb decoding */ + /* Enter Thumb mode... */ + add a4, pc, #1 /* Get the address of the Thumb block. */ + bx a4 /* Go there and start Thumb decoding. */ .code 16 .global __change_mode @@ -271,9 +275,8 @@ __change_mode: bl FUNCTION (memset) #if !defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR) /* Changes by toralf: Taken from libgloss/m68k/crt0.S - * initialize target specific stuff. Only execute these - * functions it they exist. - */ + initialize target specific stuff. Only execute these + functions it they exist. */ ldr r3, .Lhwinit cmp r3, #0 beq .LC24 @@ -285,24 +288,24 @@ __change_mode: indirect_call r3 .LC25: - movs r0, #0 /* no arguments */ - movs r1, #0 /* no argv either */ + movs r0, #0 /* No arguments. */ + movs r1, #0 /* No argv either. */ #else - /* Need to set up standard file handles */ + /* Need to set up standard file handles. */ bl FUNCTION (initialise_monitor_handles) #ifdef ARM_RDP_MONITOR - swi SWI_GetEnv /* sets r0 to point to the command line */ + swi SWI_GetEnv /* Sets r0 to point to the command line. */ movs r1, r0 #else movs r0, #AngelSWI_Reason_GetCmdLine - ldr r1, .LC30 /* Space for command line */ + ldr r1, .LC30 /* Space for command line. */ AngelSWIAsm (AngelSWI) ldr r1, .LC30 ldr r1, [r1] #endif - /* Parse string at r1 */ - movs r0, #0 /* count of arguments so far */ + /* Parse string at r1. */ + movs r0, #0 /* Count of arguments so far. */ /* Push a NULL argument onto the end of the list. */ #ifdef __thumb__ push {r0} @@ -310,7 +313,7 @@ __change_mode: stmfd sp!, {r0} #endif .LC10: -/* Skip leading blanks */ +/* Skip leading blanks. */ #ifdef __thumb__ ldrb r3, [r1] adds r1, #1 @@ -322,7 +325,7 @@ __change_mode: cmp r3, #' ' beq .LC10 -/* See whether we are scanning a string */ +/* See whether we are scanning a string. */ cmp r3, #'"' #ifdef __thumb__ beq .LC20 @@ -333,17 +336,17 @@ __change_mode: b .LC22 .LC21: - movs r2, #' ' /* terminator type */ - subs r1, r1, #1 /* adjust back to point at start char */ + movs r2, #' ' /* Terminator type. */ + subs r1, r1, #1 /* Adjust back to point at start char. */ .LC22: #else cmpne r3, #'\'' moveq r2, r3 - movne r2, #' ' /* terminator type */ - subne r1, r1, #1 /* adjust back to point at start char */ + movne r2, #' ' /* Terminator type. */ + subne r1, r1, #1 /* Adjust back to point at start char. */ #endif -/* Stack a pointer to the current argument */ +/* Stack a pointer to the current argument. */ #ifdef __thumb__ push {r1} #else @@ -359,16 +362,16 @@ __change_mode: #endif cmp r3, #0 beq .LC12 - cmp r2, r3 /* reached terminator? */ + cmp r2, r3 /* Reached terminator ? */ bne .LC11 movs r2, #0 subs r3, r1, #1 - strb r2, [r3] /* terminate the arg string */ + strb r2, [r3] /* Terminate the arg string. */ b .LC10 .LC12: - mov r1, sp /* point at stacked arg pointers */ - /* We've now got the stacked args in order reverse the */ + mov r1, sp /* Point at stacked arg pointers. */ + /* We've now got the stacked args in order, reverse them. */ #ifdef __thumb__ movs r2, r0 lsls r2, #2 @@ -390,10 +393,10 @@ __change_mode: bics r4, r5 mov sp, r4 #else - add r2, sp, r0, LSL #2 /* End of args */ - mov r3, sp /* Start of args */ + add r2, sp, r0, LSL #2 /* End of args. */ + mov r3, sp /* Start of args. */ .LC13: cmp r2, r3 - ldrhi r4,[r2, #-4] /* Reverse ends of list */ + ldrhi r4,[r2, #-4] /* Reverse ends of list. */ ldrhi r5, [r3] strhi r5, [r2, #-4]! strhi r4, [r3], #4 @@ -431,7 +434,6 @@ __change_mode: #if __thumb__ && !defined(PREFER_THUMB) /* Come out of Thumb mode. This code should be redundant. */ - mov a4, pc bx a4 @@ -441,13 +443,12 @@ change_back: /* Halt the execution. This code should never be executed. */ /* With no debug monitor, this probably aborts (eventually). With a Demon debug monitor, this halts cleanly. - With an Angel debug monitor, this will report 'Unknown SWI'. */ + With an Angel debug monitor, this will report 'Unknown SWI'. */ swi SWI_Exit #endif /* For Thumb, constants must be after the code since only positive offsets are supported for PC relative addresses. */ - .align 0 .LC0: #ifdef ARM_RDI_MONITOR @@ -457,13 +458,13 @@ change_back: /* Changes by toralf: Provide alternative "stack" variable whose value may be defined externally; .Lstack will be used instead of .LC0 if it points to a non-0 value. Also set up references to "hooks" that - may be used by the application to provide additional init code. */ - + may be used by the application to provide additional init code. */ #ifdef __pe__ .word 0x800000 #else .word 0x80000 /* Top of RAM on the PIE board. */ #endif + .Lstack: .word __stack .Lhwinit: @@ -476,7 +477,7 @@ change_back: runtime (meaning "ignore setting") for the variables, when the user does not provide the symbols. (The linker uses a weak symbol if, and only if, a normal version of the same symbol isn't provided - e.g. by a linker script or another object file.) */ + e.g. by a linker script or another object file.) */ .weak __stack .weak FUNCTION (hardware_init_hook) diff --git a/newlib/libc/sys/arm/crt0.S b/newlib/libc/sys/arm/crt0.S index 8c9f7be38..3358d7014 100644 --- a/newlib/libc/sys/arm/crt0.S +++ b/newlib/libc/sys/arm/crt0.S @@ -50,13 +50,13 @@ .global \name .thumb_func \name: -.endm +.endm #else .code 32 .macro FUNC_START name - .global \name + .global \name \name: -.endm +.endm #endif .macro indirect_call reg @@ -68,8 +68,10 @@ #endif .endm +/******************************************************************************* +* Main library startup code. +*******************************************************************************/ .align 0 - FUNC_START _mainCRTStartup FUNC_START _start #if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) @@ -399,7 +401,7 @@ __change_mode: bl FUNCTION (_init) movs r0, r4 movs r1, r5 -#endif +#endif bl FUNCTION (main) bl FUNCTION (exit) /* Should not return. */ @@ -415,12 +417,12 @@ change_back: /* Halt the execution. This code should never be executed. */ /* With no debug monitor, this probably aborts (eventually). With a Demon debug monitor, this halts cleanly. - With an Angel debug monitor, this will report 'Unknown SWI'. */ + With an Angel debug monitor, this will report 'Unknown SWI'. */ swi SWI_Exit #endif /* For Thumb, constants must be after the code since only - positive offsets are supported for PC relative addresses. */ + positive offsets are supported for PC relative addresses. */ .align 0 .LC0: #ifdef ARM_RDI_MONITOR @@ -430,7 +432,7 @@ change_back: /* Changes by toralf: Provide alternative "stack" variable whose value may be defined externally; .Lstack will be used instead of .LC0 if it points to a non-0 value. Also set up references to "hooks" that - may be used by the application to provide additional init code. */ + may be used by the application to provide additional init code. */ #ifdef __pe__ .word 0x800000 #else @@ -449,7 +451,7 @@ change_back: runtime (meaning "ignore setting") for the variables, when the user does not provide the symbols. (The linker uses a weak symbol if, and only if, a normal version of the same symbol isn't provided - e.g. by a linker script or another object file). */ + e.g. by a linker script or another object file.) */ .weak __stack .weak FUNCTION (hardware_init_hook) From patchwork Fri Jul 19 13:22:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Fedotov X-Patchwork-Id: 169249 Delivered-To: patch@linaro.org Received: by 2002:a92:4782:0:0:0:0:0 with SMTP id e2csp3858065ilk; Fri, 19 Jul 2019 06:22:50 -0700 (PDT) X-Google-Smtp-Source: APXvYqwXu9JaRRlF+JJrUtKMBZ4Nx970DAscEP33XQoxF/1pTx/qsq/RjUJQ86uBQ1moFaHQVdpw X-Received: by 2002:a17:90a:b104:: with SMTP id z4mr57587808pjq.102.1563542570647; Fri, 19 Jul 2019 06:22:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1563542570; cv=none; d=google.com; s=arc-20160816; b=qyMhmH4Q3M4L2yTh04qLsoLHz3mE7JQhGUtvybHjLZFnRZTeGEiuMKc8oFbsYL56KL 55dz4JHDEo6obEKUSHiX847AyAL0DHoYoiZuID9UgEYNjzf0sRaX6dzI+AsPOaDqQGZm 9fBnZB5l9QRDJHrNPpGTiMgiTulTT6E96rlmT+dUJpAUQjNnji4MsxGWH8P7sCkhaovi sSPyqjbBjRE9VI3ghL76+fqXZd3zcyJDoT4ESPvhrc+dR6ktRCV4K1C/2uZCF0dlls/j UZFqttBV+j8LIS/xFlyRyFG958ZztMlJOJmPQJuxAhXO5iPPwgNXfWJXJHehNaNdct14 PRMA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:delivered-to:sender:list-help:list-post:list-archive :list-subscribe:list-unsubscribe:list-id:precedence:mailing-list :dkim-signature:domainkey-signature; bh=hEdJFkB8U51LhlAkaPidWRM7mFRsHpvgXmj62DX2eXI=; b=m5+M0WAJdqRUh7BFgZw2UheqEt8JTrdH0zpjpWq9pIZgAzyqbl5jtHTqFEuac8XjRP 0noKp92IeJ1JhAxIxKpQ5kB8qs9c2uGQ3j1hN5NE8tj/XimemDMQB4PTgV6HDo9li+8d vlmVWbsnDk+nCt7N+O+jwoIDshfUCtfxlKkzjuWhXNYIdnbH5ZvZcnX+eEx1suaYNo0A FFEU31t79OeGRHj2l1WwEmDSe/Q98wfB5v5t9X68v9C7aIqzwSKzEtFi6cKBcRw6oKfC U/aWRU/CKResJLZ8GT/1I+/rYzJl4mdgvgxe2DGgqOE3/zE2f0LFA/56YmNWS6kpwc8I 7SgQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@sourceware.org header.s=default header.b=fYjqpxUG; dkim=pass header.i=@gmail.com header.s=20161025 header.b=bfcrqqVj; spf=pass (google.com: domain of newlib-return-17020-patch=linaro.org@sourceware.org designates 209.132.180.131 as permitted sender) smtp.mailfrom="newlib-return-17020-patch=linaro.org@sourceware.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Return-Path: Received: from sourceware.org (server1.sourceware.org. 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[195.5.145.226]) by smtp.gmail.com with ESMTPSA id u17sm4552307lfq.69.2019.07.19.06.22.32 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 19 Jul 2019 06:22:32 -0700 (PDT) From: alfedotov@gmail.com To: Richard.Earnshaw@arm.com, newlib@sourceware.org Cc: Alexander Fedotov Subject: [PATCH v2 2/2] [Arm] Stack Pointer and Stack Limit initialization refactored. Date: Fri, 19 Jul 2019 08:22:18 -0500 Message-Id: <20190719132218.3108-2-alfedotov@gmail.com> In-Reply-To: <20190719132218.3108-1-alfedotov@gmail.com> References: <20190719132218.3108-1-alfedotov@gmail.com> From: Alexander Fedotov SP initialization changes: 1. set default value in semihosting case as well 2. moved existing SP & SL init code for processor modes in separate routine and made it as "hook" 3. init SP for processor modes in Thumb mode as well Add new macro FN_RETURN, FN_EH_START and FN_EH_END. --- libgloss/arm/arm.h | 26 ++++ libgloss/arm/crt0.S | 281 ++++++++++++++++++++++++++----------- newlib/libc/sys/arm/arm.h | 26 ++++ newlib/libc/sys/arm/crt0.S | 281 ++++++++++++++++++++++++++----------- 4 files changed, 444 insertions(+), 170 deletions(-) -- 2.17.1 diff --git a/libgloss/arm/arm.h b/libgloss/arm/arm.h index 0489f2d92..10e5b0509 100644 --- a/libgloss/arm/arm.h +++ b/libgloss/arm/arm.h @@ -61,4 +61,30 @@ # define HAVE_CALL_INDIRECT #endif +/* A and R profiles (and legacy Arm). + Current Program Status Register (CPSR) + M[4:0] Mode bits. M[4] is always 1 for 32-bit modes. + T[5] 1: Thumb, 0: ARM instruction set + F[6] 1: disables FIQ + I[7] 1: disables IRQ + A[8] 1: disables imprecise aborts + E[9] 0: Little-endian, 1: Big-endian + J[24] 1: Jazelle instruction set + */ +#define CPSR_M_USR 0x00 /* User mode. */ +#define CPSR_M_FIQ 0x01 /* Fast Interrupt mode. */ +#define CPSR_M_IRQ 0x02 /* Interrupt mode. */ +#define CPSR_M_SVR 0x03 /* Supervisor mode. */ +#define CPSR_M_MON 0x06 /* Monitor mode. */ +#define CPSR_M_ABT 0x07 /* Abort mode. */ +#define CPSR_M_HYP 0x0A /* Hypervisor mode. */ +#define CPSR_M_UND 0x0B /* Undefined mode. */ +#define CPSR_M_SYS 0x0F /* System mode. */ +#define CPSR_M_32BIT 0x10 /* 32-bit mode. */ +#define CPSR_T_BIT 0x20 /* Thumb bit. */ +#define CPSR_F_MASK 0x40 /* FIQ bit. */ +#define CPSR_I_MASK 0x80 /* IRQ bit. */ + +#define CPSR_M_MASK 0x0F /* Mode mask except M[4]. */ + #endif /* _LIBGLOSS_ARM_H */ diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S index f21add8bc..7b3270c33 100644 --- a/libgloss/arm/crt0.S +++ b/libgloss/arm/crt0.S @@ -59,6 +59,21 @@ .endm #endif +/* Annotation for EABI unwinding tables. */ +.macro FN_EH_START +#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) + .fnstart +#endif +.endm + +.macro FN_EH_END +#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) + /* Protect against unhandled exceptions. */ + .cantunwind + .fnend +#endif +.endm + .macro indirect_call reg #ifdef HAVE_CALL_INDIRECT blx \reg @@ -68,16 +83,170 @@ #endif .endm +/* For armv4t and newer, toolchains will transparently convert + 'bx lr' to 'mov pc, lr' if needed. GCC has deprecated support + for anything older than armv4t, but this should handle that + corner case in case anyone needs it anyway. */ +.macro FN_RETURN +#if __ARM_ARCH <= 4 && __ARM_ARCH_ISA_THUMB == 0 + mov pc, lr +#else + bx lr +#endif +.endm + + + +/****************************************************************************** +* User mode only: This routine makes default target specific Stack +* +-----+ <- SL_sys, Pointer initialization for different processor modes: +* | | SL_usr FIQ, Abort, IRQ, Undefined, Supervisor, System (User) +* | SYS | and setups a default Stack Limit in-case the code has +* | USR | -=0x10000 been compiled with "-mapcs-stack-check" for FIQ and +* | | System (User) modes. +* | | +* +-----+ <- initial SP, +* becomes SP_sys Hard-wiring SL value is not ideal, since there is +* and SL_usr currently no support for checking that the heap and +* stack have not collided, or that this default 64k is +* All modes: is enough for the program being executed. However, +* +-----+ <- SL_sys, it ensures that this simple crt0 world will not +* | | SL_usr immediately cause an overflow event. +* | SYS | +* | USR | -=0x10000 We go through all execution modes and set up SP +* | | for each of them. +* +-----+ <- SP_sys, +* | | SP_usr Note: +* | SVC | -= 0x8000 Mode switch via CPSR is not allowed once in +* | | non-privileged mode, so we take care not to enter +* +-----+ <- SP_svc "User" to set up its sp, and also skip most +* | | operations if already in that mode. +* | IRQ | -= 0x2000 +* | | Input parameters: +* ^ +-----+ <- SP_und - sp - Initialized SP +* s | | - r2 - May contain SL value from semihosting +* t | UND | -= 0x1000 SYS_HEAPINFO call +* a | | Scratch registers: +* c +-----+ <- SP_und - r1 - new value of CPSR +* k | | - r2 - intermediate value (in standalone mode) +* | ABT | -= 0x1000 - r3 - new SP value +* g | | - r4 - save/restore CPSR on entry/exit +* r +-----+ <- SP_abt, +* o | | SL_fiq Declared as "weak" so that user can write and use +* w | FIQ | -= 0x1000 his own implementation if current doesn't fit. +* t | | +* h +-----+ <- initial SP, +* becomes SP_fiq +* +******************************************************************************/ + .align 0 + FUNC_START _stack_init + .weak FUNCTION (_stack_init) + FN_EH_START + + /* M profile doesn't have CPSR register. */ +#if (__ARM_ARCH_PROFILE != 'M') + /* Following code is compatible for both ARM and Thumb ISA. */ + mrs r4, CPSR + /* Test mode bits - in User of all are 0. */ + tst r4, #(CPSR_M_MASK) + /* "eq" means r4 AND #0x0F is 0. */ + beq .Lskip_cpu_modes + + mov r3, sp /* Save input SP value. */ + + /* FIQ mode, interrupts disabled. */ + mov r1, #(CPSR_M_FIQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub sl, sp, #0x1000 /* FIQ mode has its own SL. */ + + /* Abort mode, interrupts disabled. */ + mov r3, sl + mov r1, #(CPSR_M_ABT|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub r3, r3, #0x1000 + + /* Undefined mode, interrupts disabled. */ + mov r1, #(CPSR_M_UND|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub r3, r3, #0x1000 + + /* IRQ mode, interrupts disabled. */ + mov r1, #(CPSR_M_IRQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub r3, r3, #0x2000 + + /* Supervisory mode, interrupts disabled. */ + mov r1, #(CPSR_M_SVR|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + + sub r3, r3, #0x8000 /* Min size 32k. */ + bic r3, r3, #0x00FF /* Align with current 64k block. */ + bic r3, r3, #0xFF00 + +# if __ARM_ARCH >= 4 + /* System (shares regs with User) mode, interrupts disabled. */ + mov r1, #(CPSR_M_SYS|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 +# else + /* Keep this for ARMv3, but GCC actually dropped it. */ + /* Move value into user mode sp without changing modes, */ + /* via '^' form of ldm. */ + str r3, [r3, #-4] + ldmdb r3, {sp}^ +# endif + + /* Back to original mode, presumably SVC, with diabled FIQ/IRQ. */ + orr r4, r4, #(CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r4 + +.Lskip_cpu_modes: +#endif + + /* Set SL register. */ +#if defined (ARM_RDI_MONITOR) /* semihosting */ + cmp r2, #0 + beq .Lsl_forced_zero + /* Allow slop for stack overflow handling and small frames. */ +# ifdef THUMB1_ONLY + adds r2, #128 + adds r2, #128 + mov sl, r2 +# else + add sl, r2, #256 +# endif +.Lsl_forced_zero: + +#else /* standalone */ + /* r3 contains SP for System/User mode. Set SL = SP - 0x10000. */ + #ifdef THUMB1_ONLY + movs r2, #64 + lsls r2, r2, #10 + subs r2, r3, r2 + mov sl, r2 + #else + /* Still assumes 256bytes below SL. */ + sub sl, r3, #64 << 10 + #endif +#endif + + FN_RETURN + FN_EH_END + + /******************************************************************************* * Main library startup code. *******************************************************************************/ .align 0 FUNC_START _mainCRTStartup FUNC_START _start -#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) - /* Annotation for EABI unwinding tables. */ - .fnstart -#endif + FN_EH_START /* __ARM_ARCH_PROFILE is defined from GCC 4.8 onwards, however __ARM_ARCH_7A has been defined since 4.2 onwards, which is when v7-a support was added @@ -144,42 +313,33 @@ .LC32: ldr r1, [r0, #8] ldr r2, [r0, #12] - /* We skip setting sp/sl if 0 returned from semihosting. + /* We skip setting SP/SL if 0 returned from semihosting. - According to semihosting docs, if 0 returned from semihosting, the system was unable to calculate the real value, so it's ok - to skip setting sp/sl to 0 here. + to skip setting SP/SL to 0 here. - Considering M-profile processors, We might want to initialize sp by the first entry of vector table and return 0 to SYS_HEAPINFO - semihosting call, which will be skipped here. */ + semihosting call, which will be skipped here. + - Considering R-profile processors there is no automatic SP init by hardware + so we need to initialize it by default value. */ + ldr r3, .Lstack cmp r1, #0 beq .LC26 - mov sp, r1 + mov r3, r1 .LC26: - cmp r2, #0 - beq .LC27 + mov sp, r3 - /* Allow slop for stack overflow handling and small frames. */ -#ifdef THUMB1_ONLY - adds r2, #128 - adds r2, #128 - mov sl, r2 -#else - add sl, r2, #256 -#endif + /* r2 (SL value) will be used in _stack_init. */ + bl FUNCTION (_stack_init) -.LC27: -#else - /* Set up the stack pointer to a fixed value. */ + +#else /* standalone */ + /* Set up the stack pointer to a fixed value. */ /* Changes by toralf: - Allow linker script to provide stack via __stack symbol - see defintion of .Lstack - Provide "hooks" that may be used by the application to add - custom init code - see .Lhwinit and .Lswinit - - Go through all execution modes and set up stack for each of them. - Loosely based on init.s from ARM/Motorola example code. - Note: Mode switch via CPSR is not allowed once in non-privileged - mode, so we take care not to enter "User" to set up its sp, - and also skip most operations if already in that mode. */ + custom init code - see .Lhwinit and .Lswinit. */ ldr r3, .Lstack cmp r3, #0 @@ -198,57 +358,10 @@ have somehow missed it below (in which case it gets the same value as FIQ - not ideal, but better than nothing). */ mov sp, r3 -#ifdef PREFER_THUMB - /* XXX Fill in stack assignments for interrupt modes. */ -#else - mrs r2, CPSR - tst r2, #0x0F /* Test mode bits - in User of all are 0. */ - beq .LC23 /* "eq" means r2 AND #0x0F is 0. */ - msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled. */ - mov sp, r3 - sub sl, sp, #0x1000 /* This mode also has its own sl (see below). */ - - mov r3, sl - msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x1000 - - msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x1000 - - msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x2000 - - msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x8000 /* Min size 32k. */ - bic r3, r3, #0x00FF /* Align with current 64k block. */ - bic r3, r3, #0xFF00 + /* We don't care of r2 value in standalone. */ + bl FUNCTION (_stack_init) - str r3, [r3, #-4] /* Move value into user mode sp without */ - ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm. */ - orr r2, r2, #0xC0 /* Back to original mode, presumably SVC, */ - msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1. */ -#endif -.LC23: - /* Setup a default stack-limit in-case the code has been - compiled with "-mapcs-stack-check". Hard-wiring this value - is not ideal, since there is currently no support for - checking that the heap and stack have not collided, or that - this default 64k is enough for the program being executed. - However, it ensures that this simple crt0 world will not - immediately cause an overflow event: */ -#ifdef THUMB1_ONLY - movs r2, #64 - lsls r2, r2, #10 - subs r2, r3, r2 - mov sl, r2 -#else - sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl. */ -#endif #endif #endif /* Zero the memory in the .bss section. */ @@ -447,6 +560,8 @@ change_back: swi SWI_Exit #endif + FN_EH_END + /* For Thumb, constants must be after the code since only positive offsets are supported for PC relative addresses. */ .align 0 @@ -464,9 +579,6 @@ change_back: #else .word 0x80000 /* Top of RAM on the PIE board. */ #endif - -.Lstack: - .word __stack .Lhwinit: .word FUNCTION (hardware_init_hook) .Lswinit: @@ -479,17 +591,16 @@ change_back: and only if, a normal version of the same symbol isn't provided e.g. by a linker script or another object file.) */ - .weak __stack .weak FUNCTION (hardware_init_hook) .weak FUNCTION (software_init_hook) #endif #endif -#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) - /* Protect against unhandled exceptions. */ - .cantunwind - .fnend -#endif + +.Lstack: + .word __stack + .weak __stack + .LC1: .word __bss_start__ .LC2: diff --git a/newlib/libc/sys/arm/arm.h b/newlib/libc/sys/arm/arm.h index 0489f2d92..dbed81750 100644 --- a/newlib/libc/sys/arm/arm.h +++ b/newlib/libc/sys/arm/arm.h @@ -61,4 +61,30 @@ # define HAVE_CALL_INDIRECT #endif +/* A and R profiles (and legacy Arm). + Current Program Status Register (CPSR) + M[4:0] Mode bits. M[4] is always 1 for 32-bit modes. + T[5] 1: Thumb, 0: ARM instruction set + F[6] 1: disables FIQ + I[7] 1: disables IRQ + A[8] 1: disables imprecise aborts + E[9] 0: Little-endian, 1: Big-endian + J[24] 1: Jazelle instruction set + */ +#define CPSR_M_USR 0x00 /* User mode. */ +#define CPSR_M_FIQ 0x01 /* Fast Interrupt mode. */ +#define CPSR_M_IRQ 0x02 /* Interrupt mode. */ +#define CPSR_M_SVR 0x03 /* Supervisor mode. */ +#define CPSR_M_MON 0x06 /* Monitor mode. */ +#define CPSR_M_ABT 0x07 /* Abort mode. */ +#define CPSR_M_HYP 0x0A /* Hypervisor mode. */ +#define CPSR_M_UND 0x0B /* Undefined mode. */ +#define CPSR_M_SYS 0x0F /* System mode. */ +#define CPSR_M_32BIT 0x10 /* 32-bit mode. */ +#define CPSR_T_BIT 0x20 /* Thumb bit. */ +#define CPSR_F_MASK 0x40 /* FIQ bit. */ +#define CPSR_I_MASK 0x80 /* IRQ bit. */ + +#define CPSR_M_MASK 0x0F /* Mode mask except M[4] */ + #endif /* _LIBGLOSS_ARM_H */ diff --git a/newlib/libc/sys/arm/crt0.S b/newlib/libc/sys/arm/crt0.S index 3358d7014..24ccb0b04 100644 --- a/newlib/libc/sys/arm/crt0.S +++ b/newlib/libc/sys/arm/crt0.S @@ -59,6 +59,21 @@ .endm #endif +/* Annotation for EABI unwinding tables. */ +.macro FN_EH_START +#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) + .fnstart +#endif +.endm + +.macro FN_EH_END +#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) + /* Protect against unhandled exceptions. */ + .cantunwind + .fnend +#endif +.endm + .macro indirect_call reg #ifdef HAVE_CALL_INDIRECT blx \reg @@ -68,16 +83,170 @@ #endif .endm +/* For armv4t and newer, toolchains will transparently convert + 'bx lr' to 'mov pc, lr' if needed. GCC has deprecated support + for anything older than armv4t, but this should handle that + corner case in case anyone needs it anyway. */ +.macro FN_RETURN +#if __ARM_ARCH <= 4 && __ARM_ARCH_ISA_THUMB == 0 + mov pc, lr +#else + bx lr +#endif +.endm + + + +/****************************************************************************** +* User mode only: This routine makes default target specific Stack +* +-----+ <- SL_sys, Pointer initialization for different processor modes: +* | | SL_usr FIQ, Abort, IRQ, Undefined, Supervisor, System (User) +* | SYS | and setups a default Stack Limit in-case the code has +* | USR | -=0x10000 been compiled with "-mapcs-stack-check" for FIQ and +* | | System (User) modes. +* | | +* +-----+ <- initial SP, +* becomes SP_sys Hard-wiring SL value is not ideal, since there is +* and SL_usr currently no support for checking that the heap and +* stack have not collided, or that this default 64k is +* All modes: is enough for the program being executed. However, +* +-----+ <- SL_sys, it ensures that this simple crt0 world will not +* | | SL_usr immediately cause an overflow event. +* | SYS | +* | USR | -=0x10000 We go through all execution modes and set up SP +* | | for each of them. +* +-----+ <- SP_sys, +* | | SP_usr Note: +* | SVC | -= 0x8000 Mode switch via CPSR is not allowed once in +* | | non-privileged mode, so we take care not to enter +* +-----+ <- SP_svc "User" to set up its sp, and also skip most +* | | operations if already in that mode. +* | IRQ | -= 0x2000 +* | | Input parameters: +* ^ +-----+ <- SP_und - sp - Initialized SP +* s | | - r2 - May contain SL value from semihosting +* t | UND | -= 0x1000 SYS_HEAPINFO call +* a | | Scratch registers: +* c +-----+ <- SP_und - r1 - new value of CPSR +* k | | - r2 - intermediate value (in standalone mode) +* | ABT | -= 0x1000 - r3 - new SP value +* g | | - r4 - save/restore CPSR on entry/exit +* r +-----+ <- SP_abt, +* o | | SL_fiq Declared as "weak" so that user can write and use +* w | FIQ | -= 0x1000 his own implementation if current doesn't fit. +* t | | +* h +-----+ <- initial SP, +* becomes SP_fiq +* +******************************************************************************/ + .align 0 + FUNC_START _stack_init + .weak FUNCTION (_stack_init) + FN_EH_START + + /* M profile doesn't have CPSR register. */ +#if (__ARM_ARCH_PROFILE != 'M') + /* Following code is compatible for both ARM and Thumb ISA. */ + mrs r4, CPSR + /* Test mode bits - in User of all are 0. */ + tst r4, #(CPSR_M_MASK) + /* "eq" means r4 AND #0x0F is 0. */ + beq .Lskip_cpu_modes + + mov r3, sp /* Save input SP value. */ + + /* FIQ mode, interrupts disabled. */ + mov r1, #(CPSR_M_FIQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub sl, sp, #0x1000 /* FIQ mode has its own SL. */ + + /* Abort mode, interrupts disabled. */ + mov r3, sl + mov r1, #(CPSR_M_ABT|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub r3, r3, #0x1000 + + /* Undefined mode, interrupts disabled. */ + mov r1, #(CPSR_M_UND|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub r3, r3, #0x1000 + + /* IRQ mode, interrupts disabled. */ + mov r1, #(CPSR_M_IRQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + sub r3, r3, #0x2000 + + /* Supervisory mode, interrupts disabled. */ + mov r1, #(CPSR_M_SVR|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 + + sub r3, r3, #0x8000 /* Min size 32k. */ + bic r3, r3, #0x00FF /* Align with current 64k block. */ + bic r3, r3, #0xFF00 + +# if __ARM_ARCH >= 4 + /* System (shares regs with User) mode, interrupts disabled. */ + mov r1, #(CPSR_M_SYS|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r1 + mov sp, r3 +# else + /* Keep this for ARMv3, but GCC actually dropped it. */ + /* Move value into user mode sp without changing modes, */ + /* via '^' form of ldm. */ + str r3, [r3, #-4] + ldmdb r3, {sp}^ +# endif + + /* Back to original mode, presumably SVC, with diabled FIQ/IRQ. */ + orr r4, r4, #(CPSR_I_MASK|CPSR_F_MASK) + msr CPSR_c, r4 + +.Lskip_cpu_modes: +#endif + + /* Set SL register. */ +#if defined (ARM_RDI_MONITOR) /* semihosting */ + cmp r2, #0 + beq .Lsl_forced_zero + /* Allow slop for stack overflow handling and small frames. */ +# ifdef THUMB1_ONLY + adds r2, #128 + adds r2, #128 + mov sl, r2 +# else + add sl, r2, #256 +# endif +.Lsl_forced_zero: + +#else /* standalone */ + /* r3 contains SP for System/User mode. Set SL = SP - 0x10000. */ + #ifdef THUMB1_ONLY + movs r2, #64 + lsls r2, r2, #10 + subs r2, r3, r2 + mov sl, r2 + #else + /* Still assumes 256bytes below SL. */ + sub sl, r3, #64 << 10 + #endif +#endif + + FN_RETURN + FN_EH_END + + /******************************************************************************* * Main library startup code. *******************************************************************************/ .align 0 FUNC_START _mainCRTStartup FUNC_START _start -#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) - /* Annotation for EABI unwinding tables. */ - .fnstart -#endif + FN_EH_START /* Start by setting up a stack. */ #ifdef ARM_RDP_MONITOR @@ -124,42 +293,33 @@ .LC32: ldr r1, [r0, #8] ldr r2, [r0, #12] - /* We skip setting sp/sl if 0 returned from semihosting. + /* We skip setting SP/SL if 0 returned from semihosting. - According to semihosting docs, if 0 returned from semihosting, the system was unable to calculate the real value, so it's ok - to skip setting sp/sl to 0 here. + to skip setting SP/SL to 0 here. - Considering M-profile processors, We might want to initialize sp by the first entry of vector table and return 0 to SYS_HEAPINFO - semihosting call, which will be skipped here. */ + semihosting call, which will be skipped here. + - Considering R-profile processors there is no automatic SP init by hardware + so we need to initialize it by default value. */ + ldr r3, .Lstack cmp r1, #0 beq .LC26 - mov sp, r1 + mov r3, r1 .LC26: - cmp r2, #0 - beq .LC27 + mov sp, r3 - /* Allow slop for stack overflow handling and small frames. */ -#ifdef THUMB1_ONLY - adds r2, #128 - adds r2, #128 - mov sl, r2 -#else - add sl, r2, #256 -#endif + /* r2 (SL value) will be used in _stack_init. */ + bl FUNCTION (_stack_init) -.LC27: -#else - /* Set up the stack pointer to a fixed value. */ + +#else /* standalone */ + /* Set up the stack pointer to a fixed value. */ /* Changes by toralf: - Allow linker script to provide stack via __stack symbol - see defintion of .Lstack - Provide "hooks" that may be used by the application to add - custom init code - see .Lhwinit and .Lswinit - - Go through all execution modes and set up stack for each of them. - Loosely based on init.s from ARM/Motorola example code. - Note: Mode switch via CPSR is not allowed once in non-privileged - mode, so we take care not to enter "User" to set up its sp, - and also skip most operations if already in that mode. */ + custom init code - see .Lhwinit and .Lswinit. */ ldr r3, .Lstack cmp r3, #0 @@ -178,57 +338,10 @@ have somehow missed it below (in which case it gets the same value as FIQ - not ideal, but better than nothing). */ mov sp, r3 -#ifdef PREFER_THUMB - /* XXX Fill in stack assignments for interrupt modes. */ -#else - mrs r2, CPSR - tst r2, #0x0F /* Test mode bits - in User of all are 0. */ - beq .LC23 /* "eq" means r2 AND #0x0F is 0. */ - msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled. */ - mov sp, r3 - sub sl, sp, #0x1000 /* This mode also has its own sl (see below). */ - - mov r3, sl - msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x1000 - - msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x1000 - - msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x2000 - - msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled. */ - mov sp, r3 - sub r3, r3, #0x8000 /* Min size 32k. */ - bic r3, r3, #0x00FF /* Align with current 64k block. */ - bic r3, r3, #0xFF00 + /* We don't care of r2 value in standalone. */ + bl FUNCTION (_stack_init) - str r3, [r3, #-4] /* Move value into user mode sp without */ - ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm. */ - orr r2, r2, #0xC0 /* Back to original mode, presumably SVC, */ - msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1. */ -#endif -.LC23: - /* Setup a default stack-limit in-case the code has been - compiled with "-mapcs-stack-check". Hard-wiring this value - is not ideal, since there is currently no support for - checking that the heap and stack have not collided, or that - this default 64k is enough for the program being executed. - However, it ensures that this simple crt0 world will not - immediately cause an overflow event: */ -#ifdef THUMB1_ONLY - movs r2, #64 - lsls r2, r2, #10 - subs r2, r3, r2 - mov sl, r2 -#else - sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl. */ -#endif #endif #endif /* Zero the memory in the .bss section. */ @@ -421,6 +534,8 @@ change_back: swi SWI_Exit #endif + FN_EH_END + /* For Thumb, constants must be after the code since only positive offsets are supported for PC relative addresses. */ .align 0 @@ -438,9 +553,6 @@ change_back: #else .word 0x80000 /* Top of RAM on the PIE board. */ #endif - -.Lstack: - .word __stack .Lhwinit: .word FUNCTION (hardware_init_hook) .Lswinit: @@ -453,17 +565,16 @@ change_back: and only if, a normal version of the same symbol isn't provided e.g. by a linker script or another object file.) */ - .weak __stack .weak FUNCTION (hardware_init_hook) .weak FUNCTION (software_init_hook) #endif #endif -#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__) - /* Protect against unhandled exceptions. */ - .cantunwind - .fnend -#endif + +.Lstack: + .word __stack + .weak __stack + .LC1: .word __bss_start__ .LC2: