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/* The kernel call that is implemented in this file:
* m_type: SYS_SIGRETURN
*
* The parameters for this kernel call are:
* m_sigcalls.endp # process returning from handler
* m_sigcalls.sigctx # pointer to sigcontext structure
*
*/
#include "kernel/system.h"
#include <string.h>
#include <machine/cpu.h>
#if USE_SIGRETURN
/*===========================================================================*
* do_sigreturn *
*===========================================================================*/
int do_sigreturn(struct proc * caller, message * m_ptr)
{
/* POSIX style signals require sys_sigreturn to put things in order before
* the signalled process can resume execution
*/
struct sigcontext sc;
register struct proc *rp;
int proc_nr, r;
if (!isokendpt(m_ptr->m_sigcalls.endpt, &proc_nr)) return EINVAL;
if (iskerneln(proc_nr)) return EPERM;
rp = proc_addr(proc_nr);
/* Copy in the sigcontext structure. */
if ((r = data_copy(m_ptr->m_sigcalls.endpt,
(vir_bytes)m_ptr->m_sigcalls.sigctx, KERNEL,
(vir_bytes)&sc, sizeof(struct sigcontext))) != OK)
return r;
#if defined(__i386__)
/* Restore user bits of psw from sc, maintain system bits from proc. */
sc.sc_eflags = (sc.sc_eflags & X86_FLAGS_USER) |
(rp->p_reg.psw & ~X86_FLAGS_USER);
#endif
#if defined(__i386__)
/* Write back registers we allow to be restored, i.e.
* not the segment ones.
*/
rp->p_reg.di = sc.sc_edi;
rp->p_reg.si = sc.sc_esi;
rp->p_reg.fp = sc.sc_ebp;
rp->p_reg.bx = sc.sc_ebx;
rp->p_reg.dx = sc.sc_edx;
rp->p_reg.cx = sc.sc_ecx;
rp->p_reg.retreg = sc.sc_eax;
rp->p_reg.pc = sc.sc_eip;
rp->p_reg.psw = sc.sc_eflags;
rp->p_reg.sp = sc.sc_esp;
#endif
#if defined(__arm__)
rp->p_reg.psr = sc.sc_spsr;
rp->p_reg.retreg = sc.sc_r0;
rp->p_reg.r1 = sc.sc_r1;
rp->p_reg.r2 = sc.sc_r2;
rp->p_reg.r3 = sc.sc_r3;
rp->p_reg.r4 = sc.sc_r4;
rp->p_reg.r5 = sc.sc_r5;
rp->p_reg.r6 = sc.sc_r6;
rp->p_reg.r7 = sc.sc_r7;
rp->p_reg.r8 = sc.sc_r8;
rp->p_reg.r9 = sc.sc_r9;
rp->p_reg.r10 = sc.sc_r10;
rp->p_reg.fp = sc.sc_r11;
rp->p_reg.r12 = sc.sc_r12;
rp->p_reg.sp = sc.sc_usr_sp;
rp->p_reg.lr = sc.sc_usr_lr;
rp->p_reg.pc = sc.sc_pc;
#endif
/* Restore the registers. */
arch_proc_setcontext(rp, &rp->p_reg, 1, sc.trap_style);
if(sc.sc_magic != SC_MAGIC) { printf("kernel sigreturn: corrupt signal context\n"); }
#if defined(__i386__)
if (sc.sc_flags & MF_FPU_INITIALIZED)
{
memcpy(rp->p_seg.fpu_state, &sc.sc_fpu_state, FPU_XFP_SIZE);
rp->p_misc_flags |= MF_FPU_INITIALIZED; /* Restore math usage flag. */
/* force reloading FPU */
release_fpu(rp);
}
#endif
return OK;
}
#endif /* USE_SIGRETURN */
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