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Save the GP register value and restore it on longjmp.

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While formally GP is not a callee-saved register, for static linking
the link time optimization described in section 3.2.3 of the "Calling
Standard for Alpha Systems" allows the caller to rely on GP being the
value needed within setjmp() - and not restore it after return if setjmp
and the call site share a GP value.

This fixes longjmp/setjmp for statically linked programs, e.g. /rescue/csh
or the static tcsh variant from pkgsrc.
This commit is contained in:
martin 2013-03-12 19:38:20 +00:00
parent 168c675fdb
commit c06bee84e7
2 changed files with 6 additions and 2 deletions
lib/libc/arch/alpha/gen
__longjmp14.c__setjmp14.S

5
lib/libc/arch/alpha/gen/__longjmp14.c

@ -1,4 +1,4 @@
/* $NetBSD: __longjmp14.c,v 1.5 2008/04/28 20:22:55 martin Exp $ */
/* $NetBSD: __longjmp14.c,v 1.6 2013/03/12 19:38:20 martin Exp $ */
/*-
* Copyright (c) 2003 The NetBSD Foundation, Inc.
@ -56,6 +56,8 @@ __longjmp14(jmp_buf env, int val)
if (val == 0)
val = -1;
memset(&uc, 0, sizeof uc);
/* Set _UC_SIGMASK and _UC_CPU */
uc.uc_flags = _UC_SIGMASK | _UC_CPU;
@ -74,6 +76,7 @@ __longjmp14(jmp_buf env, int val)
uc.uc_mcontext.__gregs[_REG_S5] = sc->sc_regs[R_S5];
uc.uc_mcontext.__gregs[_REG_S6] = sc->sc_regs[R_S6];
uc.uc_mcontext.__gregs[_REG_RA] = sc->sc_regs[R_RA];
uc.uc_mcontext.__gregs[_REG_GP] = sc->sc_regs[R_GP];
uc.uc_mcontext.__gregs[_REG_SP] = sc->sc_sp;
uc.uc_mcontext.__gregs[_REG_PC] = sc->sc_pc;
uc.uc_mcontext.__gregs[_REG_PS] =

3
lib/libc/arch/alpha/gen/__setjmp14.S

@ -1,4 +1,4 @@
/* $NetBSD: __setjmp14.S,v 1.5 2011/06/12 05:44:36 matt Exp $ */
/* $NetBSD: __setjmp14.S,v 1.6 2013/03/12 19:38:20 martin Exp $ */
/*
* Copyright (c) 1994, 1995 Carnegie-Mellon University.
@ -55,6 +55,7 @@ LEAF(__setjmp14, 1)
stq s6, (SC_REGS+_REG_S6)(a0)
stq ra, (SC_REGS+_REG_RA)(a0)
stq sp, (SC_REGS+_REG_SP)(a0)
stq gp, (SC_REGS+_REG_GP)(a0)
/*
* get signal information