[ARM] Handle HWCAP_VFP in VFP support code

Don't set HWCAP_VFP in the processor support file; not only does it
depend on the processor features, but it also depends on the support
code being present.  Therefore, only set it if the support code
detects that we have a VFP coprocessor attached.

Also, move the VFP handling of the coprocessor access register into
the VFP support code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/setup.c

@@ -354,9 +354,6 @@ static void __init setup_processor(void)
 #ifndef CONFIG_ARM_THUMB
 	elf_hwcap &= ~HWCAP_THUMB;
 #endif
-#ifndef CONFIG_VFP
-	elf_hwcap &= ~HWCAP_VFP;
-#endif
 
 	cpu_proc_init();
 }

arch/arm/mm/proc-arm926.S

@@ -480,7 +480,7 @@ __arm926_proc_info:
 	b	__arm926_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
-	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_VFP|HWCAP_EDSP|HWCAP_JAVA
+	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_JAVA
 	.long	cpu_arm926_name
 	.long	arm926_processor_functions
 	.long	v4wbi_tlb_fns

arch/arm/mm/proc-v6.S

@@ -207,11 +207,6 @@ __v6_setup:
 #endif
 	mcr	p15, 0, r4, c2, c0, 1		@ load TTB1
 #endif /* CONFIG_MMU */
-#ifdef CONFIG_VFP
-	mrc	p15, 0, r0, c1, c0, 2
-	orr	r0, r0, #(0xf << 20)
-	mcr	p15, 0, r0, c1, c0, 2		@ Enable full access to VFP
-#endif
 	adr	r5, v6_crval
 	ldmia	r5, {r5, r6}
 	mrc	p15, 0, r0, c1, c0, 0		@ read control register
@@ -273,7 +268,7 @@ __v6_proc_info:
 	b	__v6_setup
 	.long	cpu_arch_name
 	.long	cpu_elf_name
-	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_VFP|HWCAP_EDSP|HWCAP_JAVA
+	.long	HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP|HWCAP_JAVA
 	.long	cpu_v6_name
 	.long	v6_processor_functions
 	.long	v6wbi_tlb_fns

arch/arm/vfp/vfpmodule.c

@@ -263,13 +263,24 @@ void VFP9_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
 	if (exceptions)
 		vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs);
 }
- 
+
 /*
  * VFP support code initialisation.
  */
 static int __init vfp_init(void)
 {
 	unsigned int vfpsid;
+	unsigned int cpu_arch = cpu_architecture();
+	u32 access = 0;
+
+	if (cpu_arch >= CPU_ARCH_ARMv6) {
+		access = get_copro_access();
+
+		/*
+		 * Enable full access to VFP (cp10 and cp11)
+		 */
+		set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11));
+	}
 
 	/*
 	 * First check that there is a VFP that we can use.
@@ -281,6 +292,12 @@ static int __init vfp_init(void)
 	printk(KERN_INFO "VFP support v0.3: ");
 	if (VFP_arch) {
 		printk("not present\n");
+
+		/*
+		 * Restore the copro access register.
+		 */
+		if (cpu_arch >= CPU_ARCH_ARMv6)
+			set_copro_access(access);
 	} else if (vfpsid & FPSID_NODOUBLE) {
 		printk("no double precision support\n");
 	} else {
@@ -291,9 +308,16 @@ static int __init vfp_init(void)
 			(vfpsid & FPSID_PART_MASK) >> FPSID_PART_BIT,
 			(vfpsid & FPSID_VARIANT_MASK) >> FPSID_VARIANT_BIT,
 			(vfpsid & FPSID_REV_MASK) >> FPSID_REV_BIT);
+
 		vfp_vector = vfp_support_entry;
 
 		thread_register_notifier(&vfp_notifier_block);
+
+		/*
+		 * We detected VFP, and the support code is
+		 * in place; report VFP support to userspace.
+		 */
+		elf_hwcap |= HWCAP_VFP;
 	}
 	return 0;
 }

include/asm-arm/system.h

@@ -139,19 +139,36 @@ static inline int cpu_is_xsc3(void)
 #define	cpu_is_xscale()	1
 #endif
 
-#define set_cr(x)					\
-	__asm__ __volatile__(				\
-	"mcr	p15, 0, %0, c1, c0, 0	@ set CR"	\
-	: : "r" (x) : "cc")
-
-#define get_cr()					\
-	({						\
-	unsigned int __val;				\
-	__asm__ __volatile__(				\
-	"mrc	p15, 0, %0, c1, c0, 0	@ get CR"	\
-	: "=r" (__val) : : "cc");			\
-	__val;						\
-	})
+static inline unsigned int get_cr(void)
+{
+	unsigned int val;
+	asm("mrc p15, 0, %0, c1, c0, 0	@ get CR" : "=r" (val) : : "cc");
+	return val;
+}
+
+static inline void set_cr(unsigned int val)
+{
+	asm volatile("mcr p15, 0, %0, c1, c0, 0	@ set CR"
+	  : : "r" (val) : "cc");
+}
+
+#define CPACC_FULL(n)		(3 << (n * 2))
+#define CPACC_SVC(n)		(1 << (n * 2))
+#define CPACC_DISABLE(n)	(0 << (n * 2))
+
+static inline unsigned int get_copro_access(void)
+{
+	unsigned int val;
+	asm("mrc p15, 0, %0, c1, c0, 2 @ get copro access"
+	  : "=r" (val) : : "cc");
+	return val;
+}
+
+static inline void set_copro_access(unsigned int val)
+{
+	asm volatile("mcr p15, 0, %0, c1, c0, 2 @ set copro access"
+	  : : "r" (val) : "cc");
+}
 
 extern unsigned long cr_no_alignment;	/* defined in entry-armv.S */
 extern unsigned long cr_alignment;	/* defined in entry-armv.S */