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libc: arm: fix setjmp abi non-conformance 

As per the arm Procedure Call Standard for the Arm Architecture
section 6.1.2 [1], VFP registers s16-s31 (d8-d15, q4-q7) must be
preserved across subroutine calls.

The current setjmp/longjmp implementations preserve only the core
registers, with the jump buffer size too small to store the required
co-processor registers.

In accordance with the C Library ABI for the Arm Architecture
section 6.11 [2], this patch sets _JBTYPE to long long adjusting
_JBLEN to 20.

It also emits vfp load/store instructions depending on architectural
support, predicated at compile time on ACLE feature-test macros.

[1] https://github.com/ARM-software/abi-aa/blob/main/aapcs32/aapcs32.rst
[2] https://github.com/ARM-software/abi-aa/blob/main/clibabi32/clibabi32.rst
This commit is contained in:
Victor L. Do Nascimento 2022-12-13 14:51:28 +00:00 committed by Richard Earnshaw
parent 90236c3a2c
commit 15ad816ddd
3 changed files with 47 additions and 39 deletions
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2
COPYING.NEWLIB
View File

@ -762,7 +762,7 @@ SUCH DAMAGE.
(35) - Arm Ltd
Copyright (c) 2009-2018 Arm Ltd
Copyright (c) 2009-2022 Arm Ltd
All rights reserved.
Redistribution and use in source and binary forms, with or without

8
newlib/libc/include/machine/setjmp.h
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@ -12,9 +12,13 @@ _BEGIN_STD_C
#if defined(__arm__) || defined(__thumb__)
/*
* All callee preserved registers:
* v1 - v7, fp, ip, sp, lr, f4, f5, f6, f7
* core registers:
* r4 - r10, fp, sp, lr
* VFP registers (architectural support dependent):
* d8 - d15
*/
#define _JBLEN 23
#define _JBLEN 20
#define _JBTYPE long long
#endif
#if defined(__aarch64__)

24
newlib/libc/machine/arm/setjmp.S
View File

@ -115,7 +115,7 @@ SYM (longjmp):
#else
#define RET tst lr, #1; \
moveq pc, lr ; \
.word 0xe12fff1e /* bx lr */
.inst 0xe12fff1e /* bx lr */
#endif
#ifdef __thumb2__
@ -174,9 +174,12 @@ SYM (\name):
/* Save all the callee-preserved registers into the jump buffer. */
#ifdef __thumb2__
mov ip, sp
stmea a1!, { v1-v7, fp, ip, lr }
stmia r0!, { r4-r10, fp, ip, lr }
#else
stmea a1!, { v1-v7, fp, ip, sp, lr }
stmia r0!, { r4-r10, fp, sp, lr }
#endif
#if defined __ARM_FP || defined __ARM_FEATURE_MVE
vstm r0, { d8-d15 }
#endif
#if 0 /* Simulator does not cope with FP instructions yet. */
@ -186,7 +189,7 @@ SYM (\name):
#endif
#endif
/* When setting up the jump buffer return 0. */
mov a1, #0
mov r0, #0
FUNC_END setjmp
@ -200,10 +203,13 @@ SYM (\name):
/* Restore the registers, retrieving the state when setjmp() was called. */
#ifdef __thumb2__
ldmfd a1!, { v1-v7, fp, ip, lr }
ldmia r0!, { r4-r10, fp, ip, lr }
mov sp, ip
#else
ldmfd a1!, { v1-v7, fp, ip, sp, lr }
ldmia r0!, { r4-r10, fp, sp, lr }
#endif
#if defined __ARM_FP || defined __ARM_FEATURE_MVE
vldm r0, { d8-d15 }
#endif
#if 0 /* Simulator does not cope with FP instructions yet. */
@ -214,11 +220,9 @@ SYM (\name):
#endif
/* Put the return value into the integer result register.
But if it is zero then return 1 instead. */
movs a1, a2
#ifdef __thumb2__
movs r0, r1
it eq
#endif
moveq a1, #1
moveq r0, #1
FUNC_END longjmp
#endif