cbc9586c13
- FPU context is stored only if conflict between 2 FPU users or while exporting context of a process to userspace while it is the active user of FPU - FPU has its owner (fpu_owner) which points to the process whose state is currently loaded in FPU - the FPU exception is only turned on when scheduling a process which is not the owner of FPU - FPU state is restored for the process that generated the FPU exception. This process runs immediately without letting scheduler to pick a new process to resolve the FPU conflict asap, to minimize the FPU thrashing and FPU exception hadler execution - faster all non-FPU-exception kernel entries as FPU state is not checked nor saved - removed MF_USED_FPU flag, only MF_FPU_INITIALIZED remains to signal that a process has used FPU in the past
56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/* The kernel call implemented in this file:
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* m_type: SYS_EXEC
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*
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* The parameters for this kernel call are:
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* m1_i1: PR_ENDPT (process that did exec call)
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* m1_p1: PR_STACK_PTR (new stack pointer)
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* m1_p2: PR_NAME_PTR (pointer to program name)
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* m1_p3: PR_IP_PTR (new instruction pointer)
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*/
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#include "kernel/system.h"
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#include <string.h>
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#include <minix/endpoint.h>
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#if USE_EXEC
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/*===========================================================================*
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* do_exec *
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*===========================================================================*/
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PUBLIC int do_exec(struct proc * caller, message * m_ptr)
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{
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/* Handle sys_exec(). A process has done a successful EXEC. Patch it up. */
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register struct proc *rp;
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int proc_nr;
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if(!isokendpt(m_ptr->PR_ENDPT, &proc_nr))
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return EINVAL;
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rp = proc_addr(proc_nr);
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if(rp->p_misc_flags & MF_DELIVERMSG) {
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rp->p_misc_flags &= ~MF_DELIVERMSG;
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rp->p_delivermsg_lin = 0;
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}
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/* Save command name for debugging, ps(1) output, etc. */
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if(data_copy(caller->p_endpoint, (vir_bytes) m_ptr->PR_NAME_PTR,
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KERNEL, (vir_bytes) rp->p_name, (phys_bytes) P_NAME_LEN - 1) != OK)
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strncpy(rp->p_name, "<unset>", P_NAME_LEN);
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/* Do architecture-specific exec() stuff. */
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arch_pre_exec(rp, (u32_t) m_ptr->PR_IP_PTR, (u32_t) m_ptr->PR_STACK_PTR);
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/* No reply to EXEC call */
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RTS_UNSET(rp, RTS_RECEIVING);
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/* Mark fpu_regs contents as not significant, so fpu
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* will be initialized, when it's used next time. */
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rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
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/* force reloading FPU if the current process is the owner */
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if (rp == fpu_owner)
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release_fpu();
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return(OK);
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}
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#endif /* USE_EXEC */
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