2d72cbec41
. add cpufeature detection of both . use it for both ipc and kernelcall traps, using a register for call number . SYSENTER/SYSCALL does not save any context, therefore userland has to save it . to accomodate multiple kernel entry/exit types, the entry type is recorded in the process struct. hitherto all types were interrupt (soft int, exception, hard int); now SYSENTER/SYSCALL is new, with the difference that context is not fully restored from proc struct when running the process again. this can't be done as some information is missing. . complication: cases in which the kernel has to fully change process context (i.e. sigreturn). in that case the exit type is changed from SYSENTER/SYSEXIT to soft-int (i.e. iret) and context is fully restored from the proc struct. this does mean the PC and SP must change, as the sysenter/sysexit userland code will otherwise try to restore its own context. this is true in the sigreturn case. . override all usage by setting libc_ipc=1
67 lines
1.9 KiB
C
67 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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* m2_i1: SIG_ENDPT # process returning from handler
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* m2_p1: SIG_CTXT_PTR # 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->SIG_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->SIG_ENDPT, (vir_bytes) m_ptr->SIG_CTXT_PTR,
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KERNEL, (vir_bytes) &sc, sizeof(struct sigcontext))) != OK)
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return r;
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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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#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);
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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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