From b92a66a65cb4480774066d9a3080c77eb34b7232 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Mon, 10 Sep 2012 00:35:26 +0000 Subject: powerpc: Add denormalisation exception handling for POWER6/7 On POWER6 and POWER7 if the input operand to an instruction is a denormalised single precision binary floating point value we can take a denormalisation exception where it's expected that the hypervisor (HV=1) will fix up the inputs before the instruction is run. This adds code to handle this denormalisation exception for POWER6 and POWER7. It also add a CONFIG_PPC_DENORMALISATION option and sets it in pseries/ppc64_defconfig. This is useful on bare metal systems only. Based on patch from Milton Miller. Signed-off-by: Michael Neuling Signed-off-by: Benjamin Herrenschmidt diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 98e513b..748ccaa 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -560,6 +560,14 @@ config SCHED_SMT when dealing with POWER5 cpus at a cost of slightly increased overhead in some places. If unsure say N here. +config PPC_DENORMALISATION + bool "PowerPC denormalisation exception handling" + depends on PPC_BOOK3S_64 + default "n" + ---help--- + Add support for handling denormalisation of single precision + values. Useful for bare metal only. If unsure say Y here. + config CMDLINE_BOOL bool "Default bootloader kernel arguments" diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig index db27c82..e263e6a 100644 --- a/arch/powerpc/configs/ppc64_defconfig +++ b/arch/powerpc/configs/ppc64_defconfig @@ -51,6 +51,7 @@ CONFIG_KEXEC=y CONFIG_IRQ_ALL_CPUS=y CONFIG_MEMORY_HOTREMOVE=y CONFIG_SCHED_SMT=y +CONFIG_PPC_DENORMALISATION=y CONFIG_PCCARD=y CONFIG_ELECTRA_CF=y CONFIG_HOTPLUG_PCI=m diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig index 1f65b3c..c169dfb 100644 --- a/arch/powerpc/configs/pseries_defconfig +++ b/arch/powerpc/configs/pseries_defconfig @@ -48,6 +48,7 @@ CONFIG_MEMORY_HOTREMOVE=y CONFIG_PPC_64K_PAGES=y CONFIG_PPC_SUBPAGE_PROT=y CONFIG_SCHED_SMT=y +CONFIG_PPC_DENORMALISATION=y CONFIG_HOTPLUG_PCI=m CONFIG_HOTPLUG_PCI_RPA=m CONFIG_HOTPLUG_PCI_RPA_DLPAR=m diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h index 4c25319..5f73ce6 100644 --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -126,6 +126,7 @@ #define PPC_INST_TLBIVAX 0x7c000624 #define PPC_INST_TLBSRX_DOT 0x7c0006a5 #define PPC_INST_XXLOR 0xf0000510 +#define PPC_INST_XVCPSGNDP 0xf0000780 #define PPC_INST_NAP 0x4c000364 #define PPC_INST_SLEEP 0x4c0003a4 @@ -277,6 +278,8 @@ VSX_XX1((s), a, b)) #define XXLOR(t, a, b) stringify_in_c(.long PPC_INST_XXLOR | \ VSX_XX3((t), a, b)) +#define XVCPSGNDP(t, a, b) stringify_in_c(.long (PPC_INST_XVCPSGNDP | \ + VSX_XX3((t), (a), (b)))) #define PPC_NAP stringify_in_c(.long PPC_INST_NAP) #define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP) diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index 121a90b..a1096fb 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -524,6 +524,7 @@ #define SPRN_HSRR0 0x13A /* Save/Restore Register 0 */ #define SPRN_HSRR1 0x13B /* Save/Restore Register 1 */ +#define HSRR1_DENORM 0x00100000 /* Denorm exception */ #define SPRN_TBCTL 0x35f /* PA6T Timebase control register */ #define TBCTL_FREEZE 0x0000000000000000ull /* Freeze all tbs */ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 39aa97d..5eb0056 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -275,6 +275,31 @@ vsx_unavailable_pSeries_1: STD_EXCEPTION_PSERIES(0x1300, 0x1300, instruction_breakpoint) KVM_HANDLER_PR_SKIP(PACA_EXGEN, EXC_STD, 0x1300) + . = 0x1500 + .global denorm_Hypervisor +denorm_exception_hv: + HMT_MEDIUM + mtspr SPRN_SPRG_HSCRATCH0,r13 + mfspr r13,SPRN_SPRG_HPACA + std r9,PACA_EXGEN+EX_R9(r13) + std r10,PACA_EXGEN+EX_R10(r13) + std r11,PACA_EXGEN+EX_R11(r13) + std r12,PACA_EXGEN+EX_R12(r13) + mfspr r9,SPRN_SPRG_HSCRATCH0 + std r9,PACA_EXGEN+EX_R13(r13) + mfcr r9 + +#ifdef CONFIG_PPC_DENORMALISATION + mfspr r10,SPRN_HSRR1 + mfspr r11,SPRN_HSRR0 /* save HSRR0 */ + andis. r10,r10,(HSRR1_DENORM)@h /* denorm? */ + addi r11,r11,-4 /* HSRR0 is next instruction */ + bne+ denorm_assist +#endif + + EXCEPTION_PROLOG_PSERIES_1(denorm_common, EXC_HV) + KVM_HANDLER_SKIP(PACA_EXGEN, EXC_STD, 0x1500) + #ifdef CONFIG_CBE_RAS STD_EXCEPTION_HV(0x1600, 0x1602, cbe_maintenance) KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0x1602) @@ -336,6 +361,103 @@ do_stab_bolted_pSeries: KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x900) KVM_HANDLER(PACA_EXGEN, EXC_HV, 0x982) +#ifdef CONFIG_PPC_DENORMALISATION +denorm_assist: +BEGIN_FTR_SECTION +/* + * To denormalise we need to move a copy of the register to itself. + * For POWER6 do that here for all FP regs. + */ + mfmsr r10 + ori r10,r10,(MSR_FP|MSR_FE0|MSR_FE1) + xori r10,r10,(MSR_FE0|MSR_FE1) + mtmsrd r10 + sync + fmr 0,0 + fmr 1,1 + fmr 2,2 + fmr 3,3 + fmr 4,4 + fmr 5,5 + fmr 6,6 + fmr 7,7 + fmr 8,8 + fmr 9,9 + fmr 10,10 + fmr 11,11 + fmr 12,12 + fmr 13,13 + fmr 14,14 + fmr 15,15 + fmr 16,16 + fmr 17,17 + fmr 18,18 + fmr 19,19 + fmr 20,20 + fmr 21,21 + fmr 22,22 + fmr 23,23 + fmr 24,24 + fmr 25,25 + fmr 26,26 + fmr 27,27 + fmr 28,28 + fmr 29,29 + fmr 30,30 + fmr 31,31 +FTR_SECTION_ELSE +/* + * To denormalise we need to move a copy of the register to itself. + * For POWER7 do that here for the first 32 VSX registers only. + */ + mfmsr r10 + oris r10,r10,MSR_VSX@h + mtmsrd r10 + sync + XVCPSGNDP(0,0,0) + XVCPSGNDP(1,1,1) + XVCPSGNDP(2,2,2) + XVCPSGNDP(3,3,3) + XVCPSGNDP(4,4,4) + XVCPSGNDP(5,5,5) + XVCPSGNDP(6,6,6) + XVCPSGNDP(7,7,7) + XVCPSGNDP(8,8,8) + XVCPSGNDP(9,9,9) + XVCPSGNDP(10,10,10) + XVCPSGNDP(11,11,11) + XVCPSGNDP(12,12,12) + XVCPSGNDP(13,13,13) + XVCPSGNDP(14,14,14) + XVCPSGNDP(15,15,15) + XVCPSGNDP(16,16,16) + XVCPSGNDP(17,17,17) + XVCPSGNDP(18,18,18) + XVCPSGNDP(19,19,19) + XVCPSGNDP(20,20,20) + XVCPSGNDP(21,21,21) + XVCPSGNDP(22,22,22) + XVCPSGNDP(23,23,23) + XVCPSGNDP(24,24,24) + XVCPSGNDP(25,25,25) + XVCPSGNDP(26,26,26) + XVCPSGNDP(27,27,27) + XVCPSGNDP(28,28,28) + XVCPSGNDP(29,29,29) + XVCPSGNDP(30,30,30) + XVCPSGNDP(31,31,31) +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206) + mtspr SPRN_HSRR0,r11 + mtcrf 0x80,r9 + ld r9,PACA_EXGEN+EX_R9(r13) + ld r10,PACA_EXGEN+EX_R10(r13) + ld r11,PACA_EXGEN+EX_R11(r13) + ld r12,PACA_EXGEN+EX_R12(r13) + ld r13,PACA_EXGEN+EX_R13(r13) + HRFID + b . +#endif + .align 7 /* moved from 0xe00 */ STD_EXCEPTION_HV(., 0xe02, h_data_storage) @@ -495,6 +617,7 @@ machine_check_common: STD_EXCEPTION_COMMON(0xe60, hmi_exception, .unknown_exception) STD_EXCEPTION_COMMON_ASYNC(0xf00, performance_monitor, .performance_monitor_exception) STD_EXCEPTION_COMMON(0x1300, instruction_breakpoint, .instruction_breakpoint_exception) + STD_EXCEPTION_COMMON(0x1502, denorm, .unknown_exception) #ifdef CONFIG_ALTIVEC STD_EXCEPTION_COMMON(0x1700, altivec_assist, .altivec_assist_exception) #else -- cgit v0.10.2