69 lines
1.9 KiB
C
69 lines
1.9 KiB
C
/* The kernel call that is implemented in this file:
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* m_type: SYS_SIGRETURN
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*
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* The parameters for this kernel call are:
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* m_sigcalls.endp # process returning from handler
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* m_sigcalls.sigctx # pointer to sigcontext structure
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*
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*/
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#include "kernel/system.h"
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#include <string.h>
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#include <machine/cpu.h>
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#if USE_SIGRETURN
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/*===========================================================================*
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* do_sigreturn *
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*===========================================================================*/
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int do_sigreturn(struct proc * caller, message * m_ptr)
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{
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/* POSIX style signals require sys_sigreturn to put things in order before
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* the signalled process can resume execution
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*/
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struct sigcontext sc;
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register struct proc *rp;
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int proc_nr, r;
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if (!isokendpt(m_ptr->m_sigcalls.endpt, &proc_nr)) return EINVAL;
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if (iskerneln(proc_nr)) return EPERM;
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rp = proc_addr(proc_nr);
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/* Copy in the sigcontext structure. */
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if ((r = data_copy(m_ptr->m_sigcalls.endpt,
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(vir_bytes)m_ptr->m_sigcalls.sigctx, KERNEL,
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(vir_bytes)&sc, sizeof(struct sigcontext))) != OK)
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return r;
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#if defined(__i386__)
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/* Restore user bits of psw from sc, maintain system bits from proc. */
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sc.sc_psw = (sc.sc_psw & X86_FLAGS_USER) |
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(rp->p_reg.psw & ~X86_FLAGS_USER);
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#endif
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#if defined(__i386__)
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/* Don't panic kernel if user gave bad selectors. */
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sc.sc_cs = rp->p_reg.cs;
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sc.sc_ds = rp->p_reg.ds;
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sc.sc_es = rp->p_reg.es;
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sc.sc_ss = rp->p_reg.ss;
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sc.sc_fs = rp->p_reg.fs;
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sc.sc_gs = rp->p_reg.gs;
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#endif
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/* Restore the registers. */
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arch_proc_setcontext(rp, &sc.sc_regs, 1, sc.trap_style);
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#if defined(__i386__)
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if (sc.sc_flags & MF_FPU_INITIALIZED)
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{
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memcpy(rp->p_seg.fpu_state, &sc.sc_fpu_state, FPU_XFP_SIZE);
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rp->p_misc_flags |= MF_FPU_INITIALIZED; /* Restore math usage flag. */
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/* force reloading FPU */
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release_fpu(rp);
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}
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#endif
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return OK;
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}
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#endif /* USE_SIGRETURN */
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