This patch enables support for Xilinx Virtex 4 FX singe-float FPU.
Changelog v2-v3:
-Fixed whitespaces for SAVE_FPR/REST_FPR.
-Changed description of MSR_AP bit.
-Removed the stub for APU unavailable exception.
Changelog v1->v2:
-Added MSR_AP bit definition
-Renamed CONFIG_XILINX_FPU to CONFIG_XILINX_SOFTFPU, moved it to
'Platform support' and made it Virtex4-FX-only.
-Changed SAVE_FPR/REST_FPR definition style.
Caveats:
- Hard-float binaries which rely on in-kernel math emulation will
give wrong results since they expect 64-bit double-precision instead of
32-bit single-precision numbers which Xilinx V4-FX Soft FPU produces.
Signed-off-by: Sergey Temerkhanov<temerkha...@cifronik.ru>
diff -r 626de0d94469 arch/powerpc/include/asm/ppc_asm.h
--- a/arch/powerpc/include/asm/ppc_asm.h Wed May 26 15:33:32 2010 +0400
+++ b/arch/powerpc/include/asm/ppc_asm.h Wed May 26 20:30:43 2010 +0400
@@ -85,13 +85,21 @@
#define REST_8GPRS(n, base) REST_4GPRS(n, base); REST_4GPRS(n+4, base)
#define REST_10GPRS(n, base) REST_8GPRS(n, base); REST_2GPRS(n+8, base)
+
+#ifdef CONFIG_XILINX_SOFTFPU
+#define SAVE_FPR(n, base) stfs n,THREAD_FPR0+8*TS_FPRWIDTH*(n)(base)
+#define REST_FPR(n, base) lfs n,THREAD_FPR0+8*TS_FPRWIDTH*(n)(base)
+#else
#define SAVE_FPR(n, base) stfd n,THREAD_FPR0+8*TS_FPRWIDTH*(n)(base)
+#define REST_FPR(n, base) lfd n,THREAD_FPR0+8*TS_FPRWIDTH*(n)(base)
+#endif
+
#define SAVE_2FPRS(n, base) SAVE_FPR(n, base); SAVE_FPR(n+1, base)
#define SAVE_4FPRS(n, base) SAVE_2FPRS(n, base); SAVE_2FPRS(n+2, base)
#define SAVE_8FPRS(n, base) SAVE_4FPRS(n, base); SAVE_4FPRS(n+4, base)
#define SAVE_16FPRS(n, base) SAVE_8FPRS(n, base); SAVE_8FPRS(n+8, base)
#define SAVE_32FPRS(n, base) SAVE_16FPRS(n, base); SAVE_16FPRS(n+16, base)
-#define REST_FPR(n, base) lfd n,THREAD_FPR0+8*TS_FPRWIDTH*(n)(base)
+
#define REST_2FPRS(n, base) REST_FPR(n, base); REST_FPR(n+1, base)
#define REST_4FPRS(n, base) REST_2FPRS(n, base); REST_2FPRS(n+2, base)
#define REST_8FPRS(n, base) REST_4FPRS(n, base); REST_4FPRS(n+4, base)
diff -r 626de0d94469 arch/powerpc/include/asm/reg.h
--- a/arch/powerpc/include/asm/reg.h Wed May 26 15:33:32 2010 +0400
+++ b/arch/powerpc/include/asm/reg.h Wed May 26 20:30:43 2010 +0400
@@ -30,6 +30,7 @@
#define MSR_ISF_LG 61 /* Interrupt 64b mode valid on 630 */
#define MSR_HV_LG 60 /* Hypervisor state */
#define MSR_VEC_LG 25 /* Enable AltiVec */
+#define MSR_AP_LG 25 /* Enable PPC405 APU */
#define MSR_VSX_LG 23 /* Enable VSX */
#define MSR_POW_LG 18 /* Enable Power Management */
#define MSR_WE_LG 18 /* Wait State Enable */
@@ -71,6 +72,7 @@
#define MSR_HV 0
#endif
+#define MSR_AP __MASK(MSR_AP_LG) /* Enable PPC405 APU */
#define MSR_VEC __MASK(MSR_VEC_LG) /* Enable AltiVec */
#define MSR_VSX __MASK(MSR_VSX_LG) /* Enable VSX */
#define MSR_POW __MASK(MSR_POW_LG) /* Enable Power
Management */
diff -r 626de0d94469 arch/powerpc/kernel/fpu.S
--- a/arch/powerpc/kernel/fpu.S Wed May 26 15:33:32 2010 +0400
+++ b/arch/powerpc/kernel/fpu.S Wed May 26 20:30:43 2010 +0400
@@ -57,6 +57,9 @@
_GLOBAL(load_up_fpu)
mfmsr r5
ori r5,r5,MSR_FP
+#ifdef CONFIG_XILINX_SOFTFPU
+ oris r5,r5,msr...@h
+#endif
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r5,r5,msr_...@h
@@ -85,6 +88,9 @@
toreal(r5)
PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
li r10,MSR_FP|MSR_FE0|MSR_FE1
+#ifdef CONFIG_XILINX_SOFTFPU
+ oris r10,r10,msr...@h
+#endif
andc r4,r4,r10 /* disable FP for previous task */
PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
@@ -94,6 +100,9 @@
mfspr r5,SPRN_SPRG3 /* current task's THREAD (phys) */
lwz r4,THREAD_FPEXC_MODE(r5)
ori r9,r9,MSR_FP /* enable FP for current */
+#ifdef CONFIG_XILINX_SOFTFPU
+ oris r9,r9,msr...@h
+#endif
or r9,r9,r4
#else
ld r4,PACACURRENT(r13)
@@ -124,6 +133,9 @@
_GLOBAL(giveup_fpu)
mfmsr r5
ori r5,r5,MSR_FP
+#ifdef CONFIG_XILINX_SOFTFPU
+ oris r5,r5,msr...@h
+#endif
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r5,r5,msr_...@h
@@ -145,6 +157,9 @@
beq 1f
PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
li r3,MSR_FP|MSR_FE0|MSR_FE1
+#ifdef CONFIG_XILINX_SOFTFPU
+ oris r3,r3,msr...@h
+#endif
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r3,r3,msr_...@h
diff -r 626de0d94469 arch/powerpc/kernel/head_40x.S
--- a/arch/powerpc/kernel/head_40x.S Wed May 26 15:33:32 2010 +0400
+++ b/arch/powerpc/kernel/head_40x.S Wed May 26 20:30:43 2010 +0400
@@ -420,7 +420,19 @@
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x700, program_check_exception)
+/* 0x0800 - FPU unavailable Exception */
+#ifdef CONFIG_PPC_FPU
+ START_EXCEPTION(0x0800, FloatingPointUnavailable)
+ NORMAL_EXCEPTION_PROLOG
+ beq 1f; \
+ bl load_up_fpu; /* if from user, just load it up */ \
+ b fast_exception_return; \
+1: addi r3,r1,STACK_FRAME_OVERHEAD; \
+ EXC_XFER_EE_LITE(0x800, kernel_fp_unavailable_exception)
+#else
EXCEPTION(0x0800, Trap_08, unknown_exception, EXC_XFER_EE)
+#endif
+
EXCEPTION(0x0900, Trap_09, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x0A00, Trap_0A, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x0B00, Trap_0B, unknown_exception, EXC_XFER_EE)
@@ -821,8 +833,10 @@
* The PowerPC 4xx family of processors do not have an FPU, so this just
* returns.
*/
+#ifndef CONFIG_PPC_FPU
_ENTRY(giveup_fpu)
blr
+#endif
/* This is where the main kernel code starts.
*/
diff -r 626de0d94469 arch/powerpc/platforms/Kconfig
--- a/arch/powerpc/platforms/Kconfig Wed May 26 15:33:32 2010 +0400
+++ b/arch/powerpc/platforms/Kconfig Wed May 26 20:30:43 2010 +0400
@@ -333,4 +333,9 @@
bool "Xilinx PCI host bridge support"
depends on PCI && XILINX_VIRTEX
+config XILINX_SOFTFPU
+ bool "Xilinx Soft FPU"
+ select PPC_FPU
+ depends on XILINX_VIRTEX_4_FX && !PPC40x_SIMPLE && !405GP && !405GPR
+
endmenu
--
Regards, Sergey Temerkhanov
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