svn commit: r278646 - stable/10/sys/arm/arm

Ian Lepore ian at FreeBSD.org
Fri Feb 13 00:15:14 UTC 2015


Author: ian
Date: Fri Feb 13 00:15:13 2015
New Revision: 278646
URL: https://svnweb.freebsd.org/changeset/base/278646

Log:
  MFC r276518:  Rework vfp code so it will compile on clang 3.4 and 3.5.

Modified:
  stable/10/sys/arm/arm/vfp.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/arm/arm/vfp.c
==============================================================================
--- stable/10/sys/arm/arm/vfp.c	Fri Feb 13 00:12:21 2015	(r278645)
+++ stable/10/sys/arm/arm/vfp.c	Fri Feb 13 00:15:13 2015	(r278646)
@@ -51,30 +51,35 @@ static struct undefined_handler vfp10_uh
 /* If true the VFP unit has 32 double registers, otherwise it has 16 */
 static int is_d32;
 
-/* The VFMXR command using coprocessor commands */
+/*
+ * About .fpu directives in this file...
+ *
+ * We should need simply .fpu vfpv3, but clang 3.5 has a quirk where setting
+ * vfpv3 doesn't imply that vfp2 features are also available -- both have to be
+ * explicitly set to get all the features of both.  This is probably a bug in
+ * clang, so it may get fixed and require changes here some day.  Other changes
+ * are probably coming in clang too, because there is email and open PRs
+ * indicating they want to completely disable the ability to use .fpu and
+ * similar directives in inline asm.  That would be catastrophic for us,
+ * hopefully they come to their senses.  There was also some discusion of a new
+ * syntax such as .push fpu=vfpv3; ...; .pop fpu; and that would be ideal for
+ * us, better than what we have now really.
+ *
+ * For gcc, each .fpu directive completely overrides the prior directive, unlike
+ * with clang, but luckily on gcc saying v3 implies all the v2 features as well.
+ */
+
 #define fmxr(reg, val) \
-    __asm __volatile("mcr p10, 7, %0, " __STRING(reg) " , c0, 0" :: "r"(val));
+    __asm __volatile("	.fpu vfpv2\n .fpu vfpv3\n"			\
+		     "	vmsr	" __STRING(reg) ", %0"   :: "r"(val));
 
-/* The VFMRX command using coprocessor commands */
 #define fmrx(reg) \
 ({ u_int val = 0;\
-    __asm __volatile("mrc p10, 7, %0, " __STRING(reg) " , c0, 0" : "=r"(val));\
+    __asm __volatile(" .fpu vfpv2\n .fpu vfpv3\n"			\
+		     "	vmrs	%0, " __STRING(reg) : "=r"(val));	\
     val; \
 })
 
-/*
- * Work around an issue with GCC where the asm it generates is not unified
- * syntax and fails to assemble because it expects the ldcleq instruction in the
- * form ldc<c>l, not in the UAL form ldcl<c>, and similar for stcleq.
- */
-#ifdef __clang__
-#define	LDCLNE  "ldclne "
-#define	STCLNE  "stclne "
-#else
-#define	LDCLNE  "ldcnel "
-#define	STCLNE  "stcnel "
-#endif
-
 static u_int
 get_coprocessorACR(void)
 {
@@ -103,25 +108,25 @@ vfp_init(void)
 	coproc |= COPROC10 | COPROC11;
 	set_coprocessorACR(coproc);
 	
-	fpsid = fmrx(VFPSID);		/* read the vfp system id */
-	fpexc = fmrx(VFPEXC);		/* read the vfp exception reg */
+	fpsid = fmrx(fpsid);		/* read the vfp system id */
+	fpexc = fmrx(fpexc);		/* read the vfp exception reg */
 
 	if (!(fpsid & VFPSID_HARDSOFT_IMP)) {
 		vfp_exists = 1;
 		is_d32 = 0;
-		PCPU_SET(vfpsid, fpsid);	/* save the VFPSID */
+		PCPU_SET(vfpsid, fpsid);	/* save the fpsid */
 
 		vfp_arch =
 		    (fpsid & VFPSID_SUBVERSION2_MASK) >> VFPSID_SUBVERSION_OFF;
 
 		if (vfp_arch >= VFP_ARCH3) {
-			tmp = fmrx(VMVFR0);
+			tmp = fmrx(mvfr0);
 			PCPU_SET(vfpmvfr0, tmp);
 
 			if ((tmp & VMVFR0_RB_MASK) == 2)
 				is_d32 = 1;
 
-			tmp = fmrx(VMVFR1);
+			tmp = fmrx(mvfr1);
 			PCPU_SET(vfpmvfr1, tmp);
 		}
 
@@ -161,10 +166,10 @@ vfp_bounce(u_int addr, u_int insn, struc
 	 * something tried to executate a truly invalid instruction that maps to
 	 * the VFP.
 	 */
-	fpexc = fmrx(VFPEXC);
+	fpexc = fmrx(fpexc);
 	if (fpexc & VFPEXC_EN) {
 		/* Clear any exceptions */
-		fmxr(VFPEXC, fpexc & ~(VFPEXC_EX | VFPEXC_FP2V));
+		fmxr(fpexc, fpexc & ~(VFPEXC_EX | VFPEXC_FP2V));
 
 		/* kill the process - we do not handle emulation */
 		critical_exit();
@@ -192,7 +197,7 @@ vfp_bounce(u_int addr, u_int insn, struc
 	 * the last thread to use the VFP on this core was this thread, then the
 	 * VFP state is valid, otherwise restore this thread's state to the VFP.
 	 */
-	fmxr(VFPEXC, fpexc | VFPEXC_EN);
+	fmxr(fpexc, fpexc | VFPEXC_EN);
 	curpcb = curthread->td_pcb;
 	cpu = PCPU_GET(cpu);
 	if (curpcb->pcb_vfpcpu != cpu || curthread != PCPU_GET(fpcurthread)) {
@@ -213,22 +218,26 @@ vfp_restore(struct vfp_state *vfpsave)
 {
 	uint32_t fpexc;
 
-	/* On VFPv2 we may need to restore FPINST and FPINST2 */
+	/* On vfpv3 we may need to restore FPINST and FPINST2 */
 	fpexc = vfpsave->fpexec;
 	if (fpexc & VFPEXC_EX) {
-		fmxr(VFPINST, vfpsave->fpinst);
+		fmxr(fpinst, vfpsave->fpinst);
 		if (fpexc & VFPEXC_FP2V)
-			fmxr(VFPINST2, vfpsave->fpinst2);
+			fmxr(fpinst2, vfpsave->fpinst2);
 	}
-	fmxr(VFPSCR, vfpsave->fpscr);
+	fmxr(fpscr, vfpsave->fpscr);
 
-	__asm __volatile("ldc	p10, c0, [%0], #128\n" /* d0-d15 */
-			"cmp	%1, #0\n"		/* -D16 or -D32? */
-			LDCLNE "p11, c0, [%0], #128\n"	/* d16-d31 */
-			"addeq	%0, %0, #128\n"		/* skip missing regs */
-			: : "r" (vfpsave), "r" (is_d32) : "cc");
+	__asm __volatile(
+	    " .fpu	vfpv2\n"
+	    " .fpu	vfpv3\n"
+	    " vldmia	%0!, {d0-d15}\n"	/* d0-d15 */
+	    " cmp	%1, #0\n"		/* -D16 or -D32? */
+	    " vldmiane	%0!, {d16-d31}\n"	/* d16-d31 */
+	    " addeq	%0, %0, #128\n"		/* skip missing regs */
+	    : "+&r" (vfpsave) : "r" (is_d32) : "cc"
+	    );
 
-	fmxr(VFPEXC, fpexc);
+	fmxr(fpexc, fpexc);
 }
 
 /*
@@ -241,28 +250,31 @@ vfp_store(struct vfp_state *vfpsave, boo
 {
 	uint32_t fpexc;
 
-	fpexc = fmrx(VFPEXC);		/* Is the vfp enabled? */
+	fpexc = fmrx(fpexc);		/* Is the vfp enabled? */
 	if (fpexc & VFPEXC_EN) {
 		vfpsave->fpexec = fpexc;
-		vfpsave->fpscr = fmrx(VFPSCR);
+		vfpsave->fpscr = fmrx(fpscr);
 
-		/* On VFPv2 we may need to save FPINST and FPINST2 */
+		/* On vfpv3 we may need to save FPINST and FPINST2 */
 		if (fpexc & VFPEXC_EX) {
-			vfpsave->fpinst = fmrx(VFPINST);
+			vfpsave->fpinst = fmrx(fpinst);
 			if (fpexc & VFPEXC_FP2V)
-				vfpsave->fpinst2 = fmrx(VFPINST2);
+				vfpsave->fpinst2 = fmrx(fpinst2);
 			fpexc &= ~VFPEXC_EX;
 		}
 
 		__asm __volatile(
-			"stc	p11, c0, [%0], #128\n"  /* d0-d15 */
-			"cmp	%1, #0\n"		/* -D16 or -D32? */
-			STCLNE "p11, c0, [%0], #128\n"	/* d16-d31 */
-			"addeq	%0, %0, #128\n"		/* skip missing regs */
-			: : "r" (vfpsave), "r" (is_d32) : "cc");
+		    " .fpu	vfpv2\n"
+		    " .fpu	vfpv3\n"
+		    " vstmia	%0!, {d0-d15}\n"	/* d0-d15 */
+		    " cmp	%1, #0\n"		/* -D16 or -D32? */
+		    " vstmiane	r0!, {d16-d31}\n"	/* d16-d31 */
+		    " addeq	%0, %0, #128\n"		/* skip missing regs */
+		    : "+&r" (vfpsave) : "r" (is_d32) : "cc"
+		    );
 
 		if (disable_vfp)
-			fmxr(VFPEXC , fpexc & ~VFPEXC_EN);
+			fmxr(fpexc , fpexc & ~VFPEXC_EN);
 	}
 }
 
@@ -281,9 +293,9 @@ vfp_discard(struct thread *td)
 	if (PCPU_GET(fpcurthread) == td)
 		PCPU_SET(fpcurthread, NULL);
 
-	tmp = fmrx(VFPEXC);
+	tmp = fmrx(fpexc);
 	if (tmp & VFPEXC_EN)
-		fmxr(VFPEXC, tmp & ~VFPEXC_EN);
+		fmxr(fpexc, tmp & ~VFPEXC_EN);
 }
 
 #endif


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