svn commit: r337245 - in stable/10/sys: amd64/amd64 i386/i386 i386/isa

Konstantin Belousov kib at FreeBSD.org
Fri Aug 3 14:12:39 UTC 2018


Author: kib
Date: Fri Aug  3 14:12:37 2018
New Revision: 337245
URL: https://svnweb.freebsd.org/changeset/base/337245

Log:
  MFC r336683:
  Extend ranges of the critical sections to ensure that context switch
  code never sees FPU pcb flags not consistent with the hardware state.

Modified:
  stable/10/sys/amd64/amd64/fpu.c
  stable/10/sys/amd64/amd64/machdep.c
  stable/10/sys/i386/i386/machdep.c
  stable/10/sys/i386/isa/npx.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/amd64/amd64/fpu.c
==============================================================================
--- stable/10/sys/amd64/amd64/fpu.c	Fri Aug  3 14:08:39 2018	(r337244)
+++ stable/10/sys/amd64/amd64/fpu.c	Fri Aug  3 14:12:37 2018	(r337245)
@@ -741,22 +741,22 @@ fpugetregs(struct thread *td)
 	int max_ext_n, i, owned;
 
 	pcb = td->td_pcb;
+	critical_enter();
 	if ((pcb->pcb_flags & PCB_USERFPUINITDONE) == 0) {
 		bcopy(fpu_initialstate, get_pcb_user_save_pcb(pcb),
 		    cpu_max_ext_state_size);
 		get_pcb_user_save_pcb(pcb)->sv_env.en_cw =
 		    pcb->pcb_initial_fpucw;
 		fpuuserinited(td);
+		critical_exit();
 		return (_MC_FPOWNED_PCB);
 	}
-	critical_enter();
 	if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
 		fpusave(get_pcb_user_save_pcb(pcb));
 		owned = _MC_FPOWNED_FPU;
 	} else {
 		owned = _MC_FPOWNED_PCB;
 	}
-	critical_exit();
 	if (use_xsave) {
 		/*
 		 * Handle partially saved state.
@@ -776,6 +776,7 @@ fpugetregs(struct thread *td)
 			*xstate_bv |= bit;
 		}
 	}
+	critical_exit();
 	return (owned);
 }
 
@@ -784,6 +785,7 @@ fpuuserinited(struct thread *td)
 {
 	struct pcb *pcb;
 
+	CRITICAL_ASSERT(td);
 	pcb = td->td_pcb;
 	if (PCB_USER_FPU(pcb))
 		set_pcb_flags(pcb,
@@ -842,26 +844,25 @@ fpusetregs(struct thread *td, struct savefpu *addr, ch
 
 	addr->sv_env.en_mxcsr &= cpu_mxcsr_mask;
 	pcb = td->td_pcb;
+	error = 0;
 	critical_enter();
 	if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
 		error = fpusetxstate(td, xfpustate, xfpustate_size);
-		if (error != 0) {
-			critical_exit();
-			return (error);
+		if (error == 0) {
+			bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
+			fpurestore(get_pcb_user_save_td(td));
+			set_pcb_flags(pcb, PCB_FPUINITDONE |
+			    PCB_USERFPUINITDONE);
 		}
-		bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
-		fpurestore(get_pcb_user_save_td(td));
-		critical_exit();
-		set_pcb_flags(pcb, PCB_FPUINITDONE | PCB_USERFPUINITDONE);
 	} else {
-		critical_exit();
 		error = fpusetxstate(td, xfpustate, xfpustate_size);
-		if (error != 0)
-			return (error);
-		bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
-		fpuuserinited(td);
+		if (error == 0) {
+			bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
+			fpuuserinited(td);
+		}
 	}
-	return (0);
+	critical_exit();
+	return (error);
 }
 
 /*
@@ -1004,6 +1005,7 @@ fpu_kern_enter(struct thread *td, struct fpu_kern_ctx 
 		return (0);
 	}
 	pcb = td->td_pcb;
+	critical_enter();
 	KASSERT(!PCB_USER_FPU(pcb) || pcb->pcb_save ==
 	    get_pcb_user_save_pcb(pcb), ("mangled pcb_save"));
 	ctx->flags = 0;
@@ -1014,6 +1016,7 @@ fpu_kern_enter(struct thread *td, struct fpu_kern_ctx 
 	pcb->pcb_save = fpu_kern_ctx_savefpu(ctx);
 	set_pcb_flags(pcb, PCB_KERNFPU);
 	clear_pcb_flags(pcb, PCB_FPUINITDONE);
+	critical_exit();
 	return (0);
 }
 
@@ -1029,7 +1032,6 @@ fpu_kern_leave(struct thread *td, struct fpu_kern_ctx 
 	critical_enter();
 	if (curthread == PCPU_GET(fpcurthread))
 		fpudrop();
-	critical_exit();
 	pcb->pcb_save = ctx->prev;
 	if (pcb->pcb_save == get_pcb_user_save_pcb(pcb)) {
 		if ((pcb->pcb_flags & PCB_USERFPUINITDONE) != 0) {
@@ -1044,6 +1046,7 @@ fpu_kern_leave(struct thread *td, struct fpu_kern_ctx 
 			clear_pcb_flags(pcb, PCB_FPUINITDONE);
 		KASSERT(!PCB_USER_FPU(pcb), ("unpaired fpu_kern_leave"));
 	}
+	critical_exit();
 	return (0);
 }
 

Modified: stable/10/sys/amd64/amd64/machdep.c
==============================================================================
--- stable/10/sys/amd64/amd64/machdep.c	Fri Aug  3 14:08:39 2018	(r337244)
+++ stable/10/sys/amd64/amd64/machdep.c	Fri Aug  3 14:12:37 2018	(r337245)
@@ -2380,8 +2380,10 @@ int
 set_fpregs(struct thread *td, struct fpreg *fpregs)
 {
 
+	critical_enter();
 	set_fpregs_xmm(fpregs, get_pcb_user_save_td(td));
 	fpuuserinited(td);
+	critical_exit();
 	return (0);
 }
 

Modified: stable/10/sys/i386/i386/machdep.c
==============================================================================
--- stable/10/sys/i386/i386/machdep.c	Fri Aug  3 14:08:39 2018	(r337244)
+++ stable/10/sys/i386/i386/machdep.c	Fri Aug  3 14:12:37 2018	(r337245)
@@ -3780,6 +3780,7 @@ int
 set_fpregs(struct thread *td, struct fpreg *fpregs)
 {
 
+	critical_enter();
 #ifdef CPU_ENABLE_SSE
 	if (cpu_fxsr)
 		set_fpregs_xmm((struct save87 *)fpregs,
@@ -3791,6 +3792,7 @@ set_fpregs(struct thread *td, struct fpreg *fpregs)
 #ifdef DEV_NPX
 	npxuserinited(td);
 #endif
+	critical_exit();
 	return (0);
 }
 

Modified: stable/10/sys/i386/isa/npx.c
==============================================================================
--- stable/10/sys/i386/isa/npx.c	Fri Aug  3 14:08:39 2018	(r337244)
+++ stable/10/sys/i386/isa/npx.c	Fri Aug  3 14:12:37 2018	(r337245)
@@ -1037,14 +1037,15 @@ npxgetregs(struct thread *td)
 		return (_MC_FPOWNED_NONE);
 
 	pcb = td->td_pcb;
+	critical_enter();
 	if ((pcb->pcb_flags & PCB_NPXINITDONE) == 0) {
 		bcopy(npx_initialstate, get_pcb_user_save_pcb(pcb),
 		    cpu_max_ext_state_size);
 		SET_FPU_CW(get_pcb_user_save_pcb(pcb), pcb->pcb_initial_npxcw);
 		npxuserinited(td);
+		critical_exit();
 		return (_MC_FPOWNED_PCB);
 	}
-	critical_enter();
 	if (td == PCPU_GET(fpcurthread)) {
 		fpusave(get_pcb_user_save_pcb(pcb));
 #ifdef CPU_ENABLE_SSE
@@ -1060,7 +1061,6 @@ npxgetregs(struct thread *td)
 	} else {
 		owned = _MC_FPOWNED_PCB;
 	}
-	critical_exit();
 #ifdef CPU_ENABLE_SSE
 	if (use_xsave) {
 		/*
@@ -1085,6 +1085,7 @@ npxgetregs(struct thread *td)
 		}
 	}
 #endif
+	critical_exit();
 	return (owned);
 }
 
@@ -1093,6 +1094,7 @@ npxuserinited(struct thread *td)
 {
 	struct pcb *pcb;
 
+	CRITICAL_ASSERT(td);
 	pcb = td->td_pcb;
 	if (PCB_USER_FPU(pcb))
 		pcb->pcb_flags |= PCB_NPXINITDONE;
@@ -1156,32 +1158,32 @@ npxsetregs(struct thread *td, union savefpu *addr, cha
 		addr->sv_xmm.sv_env.en_mxcsr &= cpu_mxcsr_mask;
 #endif
 	pcb = td->td_pcb;
+	error = 0;
 	critical_enter();
 	if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
 #ifdef CPU_ENABLE_SSE
 		error = npxsetxstate(td, xfpustate, xfpustate_size);
-		if (error != 0) {
-			critical_exit();
-			return (error);
-		}
-		if (!cpu_fxsr)
 #endif
-			fnclex();	/* As in npxdrop(). */
-		bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
-		fpurstor(get_pcb_user_save_td(td));
-		critical_exit();
-		pcb->pcb_flags |= PCB_NPXUSERINITDONE | PCB_NPXINITDONE;
+		if (error == 0) {
+#ifdef CPU_ENABLE_SSE
+			if (!cpu_fxsr)
+#endif
+				fnclex();	/* As in npxdrop(). */
+			bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
+			fpurstor(get_pcb_user_save_td(td));
+			pcb->pcb_flags |= PCB_NPXUSERINITDONE | PCB_NPXINITDONE;
+		}
 	} else {
-		critical_exit();
 #ifdef CPU_ENABLE_SSE
 		error = npxsetxstate(td, xfpustate, xfpustate_size);
-		if (error != 0)
-			return (error);
 #endif
-		bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
-		npxuserinited(td);
+		if (error == 0) {
+			bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
+			npxuserinited(td);
+		}
 	}
-	return (0);
+	critical_exit();
+	return (error);
 }
 
 static void
@@ -1350,6 +1352,7 @@ fpu_kern_enter(struct thread *td, struct fpu_kern_ctx 
 		return (0);
 	}
 	pcb = td->td_pcb;
+	critical_enter();
 	KASSERT(!PCB_USER_FPU(pcb) || pcb->pcb_save ==
 	    get_pcb_user_save_pcb(pcb), ("mangled pcb_save"));
 	ctx->flags = 0;
@@ -1360,6 +1363,7 @@ fpu_kern_enter(struct thread *td, struct fpu_kern_ctx 
 	pcb->pcb_save = fpu_kern_ctx_savefpu(ctx);
 	pcb->pcb_flags |= PCB_KERNNPX;
 	pcb->pcb_flags &= ~PCB_NPXINITDONE;
+	critical_exit();
 	return (0);
 }
 
@@ -1374,7 +1378,6 @@ fpu_kern_leave(struct thread *td, struct fpu_kern_ctx 
 	critical_enter();
 	if (curthread == PCPU_GET(fpcurthread))
 		npxdrop();
-	critical_exit();
 	pcb->pcb_save = ctx->prev;
 	if (pcb->pcb_save == get_pcb_user_save_pcb(pcb)) {
 		if ((pcb->pcb_flags & PCB_NPXUSERINITDONE) != 0)
@@ -1389,6 +1392,7 @@ fpu_kern_leave(struct thread *td, struct fpu_kern_ctx 
 			pcb->pcb_flags &= ~PCB_NPXINITDONE;
 		KASSERT(!PCB_USER_FPU(pcb), ("unpaired fpu_kern_leave"));
 	}
+	critical_exit();
 	return (0);
 }
 


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