ARMv7: Add VFPv3 support

This patch adds the support for VFPv3 (the kernel currently supports
VFPv2). The main difference is 32 double registers (compared to 16).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm/Kconfig

@@ -951,7 +951,7 @@ config FPE_FASTFPE
 
 config VFP
 	bool "VFP-format floating point maths"
-	depends on CPU_V6 || CPU_ARM926T
+	depends on CPU_V6 || CPU_ARM926T || CPU_V7
 	help
 	  Say Y to include VFP support code in the kernel. This is needed
 	  if your hardware includes a VFP unit.
@@ -961,6 +961,11 @@ config VFP
 
 	  Say N if your target does not have VFP hardware.
 
+config VFPv3
+	bool
+	depends on VFP
+	default y if CPU_V7
+
 endmenu
 
 menu "Userspace binary formats"

arch/arm/vfp/vfp.h

@@ -265,7 +265,11 @@ struct vfp_double {
  * which returns (double)0.0.  This is useful for the compare with
  * zero instructions.
  */
+#ifdef CONFIG_VFPv3
+#define VFP_REG_ZERO	32
+#else
 #define VFP_REG_ZERO	16
+#endif
 extern u64 vfp_get_double(unsigned int reg);
 extern void vfp_put_double(u64 val, unsigned int reg);
 

arch/arm/vfp/vfphw.S

@@ -99,12 +99,12 @@ vfp_support_entry:
 	DBGSTR1	"save old state %p", r4
 	cmp	r4, #0
 	beq	no_old_VFP_process
+	VFPFSTMIA r4, r5		@ save the working registers
 	VFPFMRX	r5, FPSCR		@ current status
 	tst	r1, #FPEXC_EX		@ is there additional state to save?
 	VFPFMRX	r6, FPINST, NE		@ FPINST (only if FPEXC.EX is set)
 	tstne	r1, #FPEXC_FP2V		@ is there an FPINST2 to read?
 	VFPFMRX	r8, FPINST2, NE		@ FPINST2 if needed (and present)
-	VFPFSTMIA r4 			@ save the working registers
 	stmia	r4, {r1, r5, r6, r8}	@ save FPEXC, FPSCR, FPINST, FPINST2
 					@ and point r4 at the word at the
 					@ start of the register dump
@@ -114,7 +114,7 @@ no_old_VFP_process:
 	DBGSTR1	"load state %p", r10
 	str	r10, [r3, r11, lsl #2]	@ update the last_VFP_context pointer
 					@ Load the saved state back into the VFP
-	VFPFLDMIA r10	 		@ reload the working registers while
+	VFPFLDMIA r10, r5		@ reload the working registers while
 					@ FPEXC is in a safe state
 	ldmia	r10, {r1, r5, r6, r8}	@ load FPEXC, FPSCR, FPINST, FPINST2
 	tst	r1, #FPEXC_EX		@ is there additional state to restore?
@@ -174,12 +174,12 @@ vfp_save_state:
 	@ r0 - save location
 	@ r1 - FPEXC
 	DBGSTR1	"save VFP state %p", r0
+	VFPFSTMIA r0, r2		@ save the working registers
 	VFPFMRX	r2, FPSCR		@ current status
 	tst	r1, #FPEXC_EX		@ is there additional state to save?
 	VFPFMRX	r3, FPINST, NE		@ FPINST (only if FPEXC.EX is set)
 	tstne	r1, #FPEXC_FP2V		@ is there an FPINST2 to read?
 	VFPFMRX	r12, FPINST2, NE	@ FPINST2 if needed (and present)
-	VFPFSTMIA r0 			@ save the working registers
 	stmia	r0, {r1, r2, r3, r12}	@ save FPEXC, FPSCR, FPINST, FPINST2
 	mov	pc, lr
 #endif
@@ -217,8 +217,15 @@ vfp_get_double:
 	fmrrd	r0, r1, d\dr
 	mov	pc, lr
 	.endr
+#ifdef CONFIG_VFPv3
+	@ d16 - d31 registers
+	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
+	mrrc	p11, 3, r0, r1, c\dr	@ fmrrd	r0, r1, d\dr
+	mov	pc, lr
+	.endr
+#endif
 
-	@ virtual register 16 for compare with zero
+	@ virtual register 16 (or 32 if VFPv3) for compare with zero
 	mov	r0, #0
 	mov	r1, #0
 	mov	pc, lr
@@ -231,3 +238,10 @@ vfp_put_double:
 	fmdrr	d\dr, r0, r1
 	mov	pc, lr
 	.endr
+#ifdef CONFIG_VFPv3
+	@ d16 - d31 registers
+	.irp	dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
+	mcrr	p11, 3, r1, r2, c\dr	@ fmdrr	r1, r2, d\dr
+	mov	pc, lr
+	.endr
+#endif

arch/arm/vfp/vfpinstr.h

@@ -52,11 +52,11 @@
 #define FEXT_TO_IDX(inst)	((inst & 0x000f0000) >> 15 | (inst & (1 << 7)) >> 7)
 
 #define vfp_get_sd(inst)	((inst & 0x0000f000) >> 11 | (inst & (1 << 22)) >> 22)
-#define vfp_get_dd(inst)	((inst & 0x0000f000) >> 12)
+#define vfp_get_dd(inst)	((inst & 0x0000f000) >> 12 | (inst & (1 << 22)) >> 18)
 #define vfp_get_sm(inst)	((inst & 0x0000000f) << 1 | (inst & (1 << 5)) >> 5)
-#define vfp_get_dm(inst)	((inst & 0x0000000f))
+#define vfp_get_dm(inst)	((inst & 0x0000000f) | (inst & (1 << 5)) >> 1)
 #define vfp_get_sn(inst)	((inst & 0x000f0000) >> 15 | (inst & (1 << 7)) >> 7)
-#define vfp_get_dn(inst)	((inst & 0x000f0000) >> 16)
+#define vfp_get_dn(inst)	((inst & 0x000f0000) >> 16 | (inst & (1 << 7)) >> 3)
 
 #define vfp_single(inst)	(((inst) & 0x0000f00) == 0xa00)
 

include/asm-arm/fpstate.h

@@ -17,14 +17,18 @@
 /*
  * VFP storage area has:
  *  - FPEXC, FPSCR, FPINST and FPINST2.
- *  - 16 double precision data registers
- *  - an implementation-dependant word of state for FLDMX/FSTMX
+ *  - 16 or 32 double precision data registers
+ *  - an implementation-dependant word of state for FLDMX/FSTMX (pre-ARMv6)
  * 
  *  FPEXC will always be non-zero once the VFP has been used in this process.
  */
 
 struct vfp_hard_struct {
+#ifdef CONFIG_VFPv3
+	__u64 fpregs[32];
+#else
 	__u64 fpregs[16];
+#endif
 #if __LINUX_ARM_ARCH__ < 6
 	__u32 fpmx_state;
 #endif
@@ -35,6 +39,7 @@ struct vfp_hard_struct {
 	 */
 	__u32 fpinst;
 	__u32 fpinst2;
+
 #ifdef CONFIG_SMP
 	__u32 cpu;
 #endif

include/asm-arm/vfp.h

@@ -7,6 +7,8 @@
 
 #define FPSID			cr0
 #define FPSCR			cr1
+#define MVFR1			cr6
+#define MVFR0			cr7
 #define FPEXC			cr8
 #define FPINST			cr9
 #define FPINST2			cr10
@@ -70,6 +72,10 @@
 #define FPSCR_IXC		(1<<4)
 #define FPSCR_IDC		(1<<7)
 
+/* MVFR0 bits */
+#define MVFR0_A_SIMD_BIT	(0)
+#define MVFR0_A_SIMD_MASK	(0xf << MVFR0_A_SIMD_BIT)
+
 /* Bit patterns for decoding the packaged operation descriptors */
 #define VFPOPDESC_LENGTH_BIT	(9)
 #define VFPOPDESC_LENGTH_MASK	(0x07 << VFPOPDESC_LENGTH_BIT)

include/asm-arm/vfpmacros.h

@@ -15,19 +15,33 @@
 	.endm
 
 	@ read all the working registers back into the VFP
-	.macro	VFPFLDMIA, base
+	.macro	VFPFLDMIA, base, tmp
 #if __LINUX_ARM_ARCH__ < 6
 	LDC	p11, cr0, [\base],#33*4		    @ FLDMIAX \base!, {d0-d15}
 #else
 	LDC	p11, cr0, [\base],#32*4		    @ FLDMIAD \base!, {d0-d15}
+#endif
+#ifdef CONFIG_VFPv3
+	VFPFMRX	\tmp, MVFR0			    @ Media and VFP Feature Register 0
+	and	\tmp, \tmp, #MVFR0_A_SIMD_MASK	    @ A_SIMD field
+	cmp	\tmp, #2			    @ 32 x 64bit registers?
+	ldceql	p11, cr0, [\base],#32*4		    @ FLDMIAD \base!, {d16-d31}
+	addne	\base, \base, #32*4		    @ step over unused register space
 #endif
 	.endm
 
 	@ write all the working registers out of the VFP
-	.macro	VFPFSTMIA, base
+	.macro	VFPFSTMIA, base, tmp
 #if __LINUX_ARM_ARCH__ < 6
 	STC	p11, cr0, [\base],#33*4		    @ FSTMIAX \base!, {d0-d15}
 #else
 	STC	p11, cr0, [\base],#32*4		    @ FSTMIAD \base!, {d0-d15}
+#endif
+#ifdef CONFIG_VFPv3
+	VFPFMRX	\tmp, MVFR0			    @ Media and VFP Feature Register 0
+	and	\tmp, \tmp, #MVFR0_A_SIMD_MASK	    @ A_SIMD field
+	cmp	\tmp, #2			    @ 32 x 64bit registers?
+	stceql	p11, cr0, [\base],#32*4		    @ FSTMIAD \base!, {d16-d31}
+	addne	\base, \base, #32*4		    @ step over unused register space
 #endif
 	.endm