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Restore user-owned bits from PSW after a signal handler, instead of

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copying complete PSW after signal handler.

This fixes a psw corruption bug reported by Jens de Smit <jst260@few.vu.nl>.
This commit is contained in:
Ben Gras
2007-05-08 15:43:00 +00:00
parent 56a68dc32b
commit b00f287449
2 changed files with 17 additions and 10 deletions
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5
kernel/system/do_sigreturn.c
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@@ -10,6 +10,7 @@
#include "../system.h"
#include <string.h>
#include <signal.h>
#include <ibm/cpu.h>
#include <sys/sigcontext.h>
#if USE_SIGRETURN
@@ -38,7 +39,9 @@ message *m_ptr; /* pointer to request message */
if (src_phys == 0) return(EFAULT);
phys_copy(src_phys, vir2phys(&sc), (phys_bytes) sizeof(struct sigcontext));
sc.sc_psw = rp->p_reg.psw;
/* Restore user bits of psw from sc, maintain system bits from proc. */
sc.sc_psw = (sc.sc_psw & X86_FLAGS_USER) |
(rp->p_reg.psw & ~X86_FLAGS_USER);
#if (_MINIX_CHIP == _CHIP_INTEL)
/* Don't panic kernel if user gave bad selectors. */