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Backout changes trying to inherit floating-point environment, although

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POSIX (susv3) requires this, but it is unclear what should be inherited,
duplicating whole 387 stack for new thread seems to be unnecessary and
dangerous. Revert to previous code, force a new thread to be started with
clean FP state.
This commit is contained in:
David Xu 2006-05-29 02:58:37 +00:00
parent 46f1e0d36c
commit 5d84379dd6
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=159027
3 changed files with 1 additions and 40 deletions
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3
sys/i386/i386/vm_machdep.c
View File

@ -393,8 +393,7 @@ cpu_set_upcall(struct thread *td, struct thread *td0)
* more analysis) (need a good safe default).
*/
bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
pcb2->pcb_flags &= ~PCB_NPXTRAP;
npx_fork_thread(td0, td);
pcb2->pcb_flags &= ~(PCB_NPXTRAP|PCB_NPXINITDONE);
/*
* Create a new fresh stack for the new thread.

3
sys/i386/include/npx.h
View File

@ -138,8 +138,6 @@ union savefpu {
#ifdef _KERNEL
struct thread;
#define IO_NPX 0x0F0 /* Numeric Coprocessor */
#define IO_NPXSIZE 16 /* 80387/80487 NPX registers */
@ -157,7 +155,6 @@ void npxinit(u_short control);
void npxsave(union savefpu *addr);
void npxsetregs(struct thread *td, union savefpu *addr);
int npxtrap(void);
void npx_fork_thread(struct thread *td, struct thread *newtd);
#endif

35
sys/i386/isa/npx.c
View File

@ -942,41 +942,6 @@ npxsetregs(td, addr)
curthread->td_pcb->pcb_flags |= PCB_NPXINITDONE;
}
/*
* POSIX requires new thread to inherit floating-point environment.
*/
void
npx_fork_thread(struct thread *td, struct thread *newtd)
{
union savefpu *state;
u_int32_t mxcsr;
u_int32_t cw;
if (!(td->td_pcb->pcb_flags & PCB_NPXINITDONE)) {
newtd->td_pcb->pcb_flags &= ~PCB_NPXINITDONE;
return;
}
state = &newtd->td_pcb->pcb_save;
/* get control word */
if (npxgetregs(td, state))
return;
if (cpu_fxsr) {
mxcsr = state->sv_xmm.sv_env.en_mxcsr;
cw = state->sv_xmm.sv_env.en_cw;
} else {
cw = state->sv_87.sv_env.en_cw;
mxcsr = 0;
}
bcopy(&npx_cleanstate, state, sizeof(*state));
if (cpu_fxsr) {
state->sv_xmm.sv_env.en_cw = cw;
state->sv_xmm.sv_env.en_mxcsr = mxcsr;
} else
state->sv_87.sv_env.en_cw = cw;
newtd->td_pcb->pcb_flags |= PCB_NPXINITDONE;
}
static void
fpusave(addr)
union savefpu *addr;