282 lines
7.0 KiB
ArmAsm
282 lines
7.0 KiB
ArmAsm
/* This is a simple version of setjmp and longjmp.
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Nick Clifton, Cygnus Solutions, 13 June 1997. */
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#include "arm-acle-compat.h"
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/* ANSI concatenation macros. */
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#define CONCAT(a, b) CONCAT2(a, b)
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#define CONCAT2(a, b) a##b
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#ifndef __USER_LABEL_PREFIX__
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#error __USER_LABEL_PREFIX__ not defined
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#endif
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#define SYM(x) CONCAT (__USER_LABEL_PREFIX__, x)
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#ifdef __ELF__
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#define TYPE(x) .type SYM(x),function
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#define SIZE(x) .size SYM(x), . - SYM(x)
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#else
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#define TYPE(x)
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#define SIZE(x)
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#endif
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/* Jump buffer allocation sizes. */
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#define JUMPBUF_CORE_REGS_SIZE (10 * 4)
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#define JUMPBUF_FP_REGS_SIZE (8 * 8)
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#define JUMPBUF_PAC (JUMPBUF_CORE_REGS_SIZE + JUMPBUF_FP_REGS_SIZE + 0)
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/* Arm/Thumb interworking support:
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The interworking scheme expects functions to use a BX instruction
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to return control to their parent. Since we need this code to work
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in both interworked and non-interworked environments as well as with
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older processors which do not have the BX instruction we do the
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following:
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Test the return address.
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If the bottom bit is clear perform an "old style" function exit.
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(We know that we are in ARM mode and returning to an ARM mode caller).
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Otherwise use the BX instruction to perform the function exit.
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We know that we will never attempt to perform the BX instruction on
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an older processor, because that kind of processor will never be
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interworked, and a return address with the bottom bit set will never
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be generated.
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In addition, we do not actually assemble the BX instruction as this would
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require us to tell the assembler that the processor is an ARM7TDMI and
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it would store this information in the binary. We want this binary to be
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able to be linked with binaries compiled for older processors however, so
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we do not want such information stored there.
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If we are running using the APCS-26 convention however, then we never
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test the bottom bit, because this is part of the processor status.
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Instead we just do a normal return, since we know that we cannot be
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returning to a Thumb caller - the Thumb does not support APCS-26.
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Function entry is much simpler. If we are compiling for the Thumb we
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just switch into ARM mode and then drop through into the rest of the
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function. The function exit code will take care of the restore to
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Thumb mode.
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For Thumb-2 do everything in Thumb mode. */
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.syntax unified
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/* GCC 12.1 and later will tell the assembler exactly which floating
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point (or MVE) unit is required and we don't want to override
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that. Conversely, older versions of the compiler don't pass this
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information so we need to enable the VFP version that is most
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appropriate. The choice here should support all suitable VFP
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versions that the older toolchains can handle. */
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#if __GNUC__ && __GNUC__ < 12
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/* Ensure that FPU instructions are correctly compiled and, likewise,
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the appropriate build attributes are added to the resulting object
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file. Check whether the MVE extension is present and whether
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we have support for hardware floating point-operations. VFPxd
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covers all the cases we need in this file for hardware
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floating-point and should be compatible with all required FPUs
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that we need to support. */
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# if __ARM_FP
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.fpu vfpxd
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# endif
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# if __ARM_FEATURE_MVE
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.arch_extension mve
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# endif
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#endif
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#if __ARM_ARCH_ISA_THUMB == 1 && !__ARM_ARCH_ISA_ARM
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/* ARMv6-M-like has to be implemented in Thumb mode. */
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.thumb
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.thumb_func
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.globl SYM (setjmp)
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TYPE (setjmp)
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SYM (setjmp):
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/* Save registers in jump buffer. */
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stmia r0!, {r4, r5, r6, r7}
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mov r1, r8
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mov r2, r9
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mov r3, r10
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mov r4, fp
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mov r5, sp
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mov r6, lr
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stmia r0!, {r1, r2, r3, r4, r5, r6}
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subs r0, r0, #40
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/* Restore callee-saved low regs. */
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ldmia r0!, {r4, r5, r6, r7}
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/* Return zero. */
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movs r0, #0
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bx lr
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.thumb_func
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.globl SYM (longjmp)
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TYPE (longjmp)
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SYM (longjmp):
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/* Restore High regs. */
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adds r0, r0, #16
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ldmia r0!, {r2, r3, r4, r5, r6}
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mov r8, r2
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mov r9, r3
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mov r10, r4
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mov fp, r5
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mov sp, r6
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ldmia r0!, {r3} /* lr */
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/* Restore low regs. */
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subs r0, r0, #40
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ldmia r0!, {r4, r5, r6, r7}
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/* Return the result argument, or 1 if it is zero. */
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movs r0, r1
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bne 1f
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movs r0, #1
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1:
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bx r3
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#else
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#ifdef __APCS_26__
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#define RET movs pc, lr
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#elif defined(__thumb2__)
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#define RET bx lr
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#else
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#define RET tst lr, #1; \
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moveq pc, lr ; \
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.inst 0xe12fff1e /* bx lr */
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#endif
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#ifdef __thumb2__
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.macro COND where when
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i\where \when
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.endm
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#else
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.macro COND where when
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.endm
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#endif
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#if defined(__thumb2__)
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.macro MODE
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.thumb
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.thumb_func
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.endm
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.macro PROLOGUE name
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.endm
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#elif defined(__thumb__)
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#define MODE .thumb_func
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.macro PROLOGUE name
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.code 16
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bx pc
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nop
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.code 32
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SYM (.arm_start_of.\name):
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.endm
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#else /* Arm */
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#define MODE .code 32
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.macro PROLOGUE name
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.endm
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#endif
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.macro FUNC_START name
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.text
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.align 2
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MODE
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.globl SYM (\name)
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.fnstart
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.cfi_startproc
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TYPE (\name)
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SYM (\name):
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PROLOGUE \name
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.endm
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.macro FUNC_END name
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RET
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.cfi_endproc
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.fnend
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SIZE (\name)
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.endm
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/* --------------------------------------------------------------------
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int setjmp (jmp_buf);
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-------------------------------------------------------------------- */
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FUNC_START setjmp
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#if __ARM_FEATURE_PAC_DEFAULT
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# if __ARM_FEATURE_BTI_DEFAULT
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pacbti ip, lr, sp
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# else
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pac ip, lr, sp
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# endif /* __ARM_FEATURE_BTI_DEFAULT */
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mov r3, ip
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str r3, [r0, #JUMPBUF_PAC]
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.cfi_register 143, 12
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#else
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# if __ARM_FEATURE_BTI_DEFAULT
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bti
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# endif /* __ARM_FEATURE_BTI_DEFAULT */
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#endif /* __ARM_FEATURE_PAC_DEFAULT */
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/* Save all the callee-preserved registers into the jump buffer. */
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#ifdef __thumb2__
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mov ip, sp
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stmia r0!, { r4-r10, fp, ip, lr }
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#else
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stmia r0!, { r4-r10, fp, sp, lr }
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#endif
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#if defined __ARM_FP || defined __ARM_FEATURE_MVE
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vstm r0, { d8-d15 }
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#endif
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/* When setting up the jump buffer return 0. */
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mov r0, #0
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#if __ARM_FEATURE_PAC_DEFAULT
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mov ip, r3
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aut ip, lr, sp
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#endif /* __ARM_FEATURE_PAC_DEFAULT */
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FUNC_END setjmp
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/* --------------------------------------------------------------------
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volatile void longjmp (jmp_buf, int);
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-------------------------------------------------------------------- */
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FUNC_START longjmp
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#if __ARM_FEATURE_BTI_DEFAULT
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bti
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#endif /* __ARM_FEATURE_BTI_DEFAULT */
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#if __ARM_FEATURE_PAC_DEFAULT
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/* Keep original jmpbuf address for retrieving pac-code
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for authentication. */
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mov r2, r0
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#endif /* __ARM_FEATURE_PAC_DEFAULT */
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/* If we have stack extension code it ought to be handled here. */
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/* Restore the registers, retrieving the state when setjmp() was called. */
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#ifdef __thumb2__
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ldmia r0!, { r4-r10, fp, ip, lr }
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mov sp, ip
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#else
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ldmia r0!, { r4-r10, fp, sp, lr }
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#endif
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#if defined __ARM_FP || defined __ARM_FEATURE_MVE
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vldm r0, { d8-d15 }
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#endif
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/* Put the return value into the integer result register.
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But if it is zero then return 1 instead. */
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movs r0, r1
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it eq
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moveq r0, #1
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#if __ARM_FEATURE_PAC_DEFAULT
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ldr ip, [r2, #JUMPBUF_PAC]
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aut ip, lr, sp
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#endif /* __ARM_FEATURE_PAC_DEFAULT */
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FUNC_END longjmp
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#endif
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