i386 longjmp: Restore stack first, then signal mask.
Otherwise, a pending signal may be delivered on the wrong stack when we restore the signal mask. While here: - Tidy the code a little bit. - Sprinkle comments to explain what's going on. - Use forward branches for statically predicted not-taken. => val==0 is unlikely in longjmp PR lib/57946
This commit is contained in:
riastradh
parent
df443a3d17
commit
3e7604f627
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@ -1,4 +1,4 @@
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/* $NetBSD: setjmp.S,v 1.17 2014/05/23 03:05:56 uebayasi Exp $ */
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/* $NetBSD: setjmp.S,v 1.18 2024/04/04 00:46:41 riastradh Exp $ */
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/*-
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* Copyright (c) 1990 The Regents of the University of California.
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@ -36,7 +36,7 @@
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#include <machine/asm.h>
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#if defined(LIBC_SCCS)
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RCSID("$NetBSD: setjmp.S,v 1.17 2014/05/23 03:05:56 uebayasi Exp $")
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RCSID("$NetBSD: setjmp.S,v 1.18 2024/04/04 00:46:41 riastradh Exp $")
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#endif
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/*
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@ -49,12 +49,24 @@
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* The previous signal state is restored.
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*/
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/*
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* setjmp(jmp_buf env@esp[4,8))
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*
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* ELF symbol: __setjmp14, because the size of jmp_buf changed on some
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* platforms in 1.4.
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*/
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ENTRY(__setjmp14)
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movl 4(%esp),%ecx
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movl 0(%esp),%edx
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movl %edx, 0(%ecx)
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movl %ebx, 4(%ecx)
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movl %esp, 8(%ecx)
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/*
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* Save the callee-saves registers: %ebp, %ebx, %edi, %esi,
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* plus %esp and the return address on the stack since it
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* will be overwritten if the caller makes any subroutine
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* calls before longjmp.
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*/
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movl 4(%esp),%ecx /* ecx := env */
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movl 0(%esp),%edx /* edx := return address */
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movl %edx,0(%ecx)
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movl %ebx,4(%ecx)
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movl %esp,8(%ecx)
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movl %ebp,12(%ecx)
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movl %esi,16(%ecx)
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movl %edi,20(%ecx)
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@ -63,49 +75,65 @@ ENTRY(__setjmp14)
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leal 24(%ecx),%edx
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PIC_PROLOGUE
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pushl %edx
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pushl $0
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pushl $0
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pushl %edx /* oset (signal mask saved to) */
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pushl $0 /* set := NULL */
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pushl $0 /* how := 0 (ignored) */
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#ifdef __PIC__
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call PIC_PLT(_C_LABEL(__sigprocmask14))
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#else
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call _C_LABEL(__sigprocmask14)
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#endif
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addl $12,%esp
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addl $12,%esp /* pop sigprocmask args */
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PIC_EPILOGUE
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xorl %eax,%eax
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xorl %eax,%eax /* return 0 first time around */
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ret
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END(__setjmp14)
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/*
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* longjmp(jmp_buf env@esp[4,8), int val@[8,12))
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*
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* ELF symbol: __longjmp14, because the size of jmp_buf changed on some
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* platforms in 1.4.
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*/
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ENTRY(__longjmp14)
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/* Restore the signal mask. */
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movl 4(%esp),%ecx
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leal 24(%ecx),%edx
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PIC_PROLOGUE
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pushl $0
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pushl %edx
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pushl $3 /* SIG_SETMASK */
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#ifdef __PIC__
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call PIC_PLT(_C_LABEL(__sigprocmask14))
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#else
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call _C_LABEL(__sigprocmask14)
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#endif
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addl $12,%esp
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PIC_EPILOGUE
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movl 4(%esp),%edx
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movl 8(%esp),%eax
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movl 0(%edx),%ecx
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/*
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* Restore the callee-saves registers: %ebp, %ebx, %edi, %esi,
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* plus %esp and the return address on the stack.
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*/
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movl 4(%esp),%edx /* edx := env */
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movl 8(%esp),%eax /* eax := val */
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movl 0(%edx),%ecx /* ecx := return address */
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movl 4(%edx),%ebx
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movl 8(%edx),%esp
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movl 12(%edx),%ebp
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movl 16(%edx),%esi
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movl 20(%edx),%edi
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testl %eax,%eax
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jnz 1f
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incl %eax
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1: movl %ecx,0(%esp)
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ret
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movl %ecx,0(%esp) /* restore return address */
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/* Restore the signal mask. */
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leal 24(%edx),%edx
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pushl %eax /* save val@eax */
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PIC_PROLOGUE
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pushl $0 /* oset := NULL */
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pushl %edx /* set (signal mask restored from) */
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pushl $3 /* how := SIG_SETMASK */
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#ifdef __PIC__
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call PIC_PLT(_C_LABEL(__sigprocmask14))
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#else
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call _C_LABEL(__sigprocmask14)
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#endif
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addl $12,%esp /* pop sigprocmask args */
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PIC_EPILOGUE
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popl %eax /* restore val@eax */
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testl %eax,%eax /* val == 0? */
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jz 3f /* jump if val == 0 */
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ret /* return val@eax */
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3: incl %eax /* val@eax := 1 */
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ret /* return val@eax */
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END(__longjmp14)
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@ -1,4 +1,4 @@
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/* $NetBSD: sigsetjmp.S,v 1.18 2014/05/23 02:34:19 uebayasi Exp $ */
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/* $NetBSD: sigsetjmp.S,v 1.19 2024/04/04 00:46:41 riastradh Exp $ */
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/*-
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* Copyright (c) 1990 The Regents of the University of California.
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@ -36,76 +36,104 @@
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#include <machine/asm.h>
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#if defined(LIBC_SCCS)
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RCSID("$NetBSD: sigsetjmp.S,v 1.18 2014/05/23 02:34:19 uebayasi Exp $")
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RCSID("$NetBSD: sigsetjmp.S,v 1.19 2024/04/04 00:46:41 riastradh Exp $")
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#endif
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/*
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* sigsetjmp(sigjmp_buf env@esp[4,8), savemask@esp[8,12))
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*
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* ELF symbol: __sigsetjmp14, because the size of sigjmp_buf changed on
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* some platforms in 1.4.
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*/
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ENTRY(__sigsetjmp14)
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movl 4(%esp),%ecx
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movl 0(%esp),%edx
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movl %edx, 0(%ecx)
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movl %ebx, 4(%ecx)
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movl %esp, 8(%ecx)
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/*
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* Save the callee-saves registers: %ebp, %ebx, %edi, %esi,
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* plus %esp and the return address on the stack since it
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* will be overwritten if the caller makes any subroutine
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* calls before siglongjmp.
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*/
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movl 4(%esp),%ecx /* ecx := env */
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movl 0(%esp),%edx /* edx := return address */
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movl %edx,0(%ecx)
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movl %ebx,4(%ecx)
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movl %esp,8(%ecx)
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movl %ebp,12(%ecx)
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movl %esi,16(%ecx)
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movl %edi,20(%ecx)
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/* Check if we should save the signal mask, and remember it. */
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movl 8(%esp),%eax
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movl 8(%esp),%eax /* eax := savemask */
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movl %eax,40(%ecx)
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testl %eax,%eax
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jz 2f /* no, skip */
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testl %eax,%eax /* savemask == 0? */
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jz 2f /* jump if savemask == 0 */
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/* Get the signal mask. */
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leal 24(%ecx),%edx
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PIC_PROLOGUE
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pushl %edx
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pushl $0
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pushl $0
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pushl %edx /* oset (signal mask saved to) */
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pushl $0 /* set := NULL */
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pushl $0 /* how := 0 (ignored) */
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#ifdef __PIC__
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call PIC_PLT(_C_LABEL(__sigprocmask14))
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#else
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call _C_LABEL(__sigprocmask14)
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#endif
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addl $12,%esp
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addl $12,%esp /* pop sigprocmask args */
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PIC_EPILOGUE
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2: xorl %eax,%eax
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2: xorl %eax,%eax /* return 0 first time around */
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ret
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END(__sigsetjmp14)
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/*
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* siglongjmp(sigjmp_buf env@esp[4,8), int val@[8,12))
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*
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* ELF symbol: __siglongjmp14, because the size of sigjmp_buf changed
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* on some platforms in 1.4.
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*/
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ENTRY(__siglongjmp14)
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/* Check to see if we need to restore the signal mask. */
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movl 4(%esp),%ecx
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cmpl $0,40(%ecx)
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jz 2f /* no, skip */
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/* Restore the signal mask. */
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leal 24(%ecx),%edx
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PIC_PROLOGUE
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pushl $0
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pushl %edx
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pushl $3 /* SIG_SETMASK */
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#ifdef __PIC__
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call PIC_PLT(_C_LABEL(__sigprocmask14))
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#else
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call _C_LABEL(__sigprocmask14)
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#endif
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addl $12,%esp
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PIC_EPILOGUE
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2: movl 4(%esp),%edx
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movl 8(%esp),%eax
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movl 0(%edx),%ecx
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/*
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* Restore the callee-saves registers: %ebp, %ebx, %edi, %esi,
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* plus %esp and the return address on the stack.
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*/
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movl 4(%esp),%edx /* edx := env */
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movl 8(%esp),%eax /* eax := val */
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movl 0(%edx),%ecx /* ecx := return address */
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movl 4(%edx),%ebx
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movl 8(%edx),%esp
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movl 12(%edx),%ebp
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movl 16(%edx),%esi
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movl 20(%edx),%edi
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testl %eax,%eax
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jnz 3f
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incl %eax
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3: movl %ecx,0(%esp)
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ret
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movl %ecx,0(%esp) /* restore return address */
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/* Check to see if we need to restore the signal mask. */
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cmpl $0,40(%edx) /* savemask == 0 */
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jz 2f /* jump if savemask == 0 */
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/* Restore the signal mask. */
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leal 24(%edx),%edx
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pushl %eax /* save val@eax */
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PIC_PROLOGUE
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pushl $0 /* oset := NULL */
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pushl %edx /* set (signal mask restored from) */
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pushl $3 /* how := SIG_SETMASK */
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#ifdef __PIC__
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call PIC_PLT(_C_LABEL(__sigprocmask14))
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#else
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call _C_LABEL(__sigprocmask14)
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#endif
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addl $12,%esp /* pop sigprocmask args */
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PIC_EPILOGUE
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popl %eax /* restore val@eax */
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2: testl %eax,%eax /* val == 0? */
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jz 3f /* jump if val == 0 */
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ret /* return val@eax */
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3: incl %eax /* val@eax := 1 */
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ret /* return val@eax */
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END(__siglongjmp14)
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@ -1,4 +1,4 @@
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/* $NetBSD: t_sigstack.c,v 1.8 2024/04/04 00:46:30 riastradh Exp $ */
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/* $NetBSD: t_sigstack.c,v 1.9 2024/04/04 00:46:42 riastradh Exp $ */
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/*-
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* Copyright (c) 2024 The NetBSD Foundation, Inc.
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@ -27,7 +27,7 @@
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: t_sigstack.c,v 1.8 2024/04/04 00:46:30 riastradh Exp $");
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__RCSID("$NetBSD: t_sigstack.c,v 1.9 2024/04/04 00:46:42 riastradh Exp $");
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#include <setjmp.h>
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#include <signal.h>
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@ -81,10 +81,18 @@ on_sigusr1(int signo, siginfo_t *si, void *ctx)
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* On some architectures, this is broken. Those that appear to
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* get this right are:
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*
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* aarch64, alpha, m68k, or1k, powerpc, powerpc64, riscv,
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* vax, x86_64
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* aarch64
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* alpha
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* i386
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* m68k
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* or1k
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* powerpc
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* powerpc64
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* riscv
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* vax
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* x86_64
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*/
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#if defined __arm__ || defined __hppa__ || defined __i386__ || \
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#if defined __arm__ || defined __hppa__ || \
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defined __ia64__ || defined __mips__ || defined __sh3__ || \
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defined __sparc__ || defined __sparc64__
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if (nentries > 0)
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