From 44e9309f1f357794b7ae93d5f3e3e6f11d2b8a7f Mon Sep 17 00:00:00 2001 From: Haren Myneni Date: Thu, 6 Dec 2012 21:51:04 +0000 Subject: [PATCH] powerpc: Implement PPR save/restore [PATCH 6/6] powerpc: Implement PPR save/restore When the task enters in to kernel space, the user defined priority (PPR) will be saved in to PACA at the beginning of first level exception vector and then copy from PACA to thread_info in second level vector. PPR will be restored from thread_info before exits the kernel space. P7/P8 temporarily raises the thread priority to higher level during exception until the program executes HMT_* calls. But it will not modify PPR register. So we save PPR value whenever some register is available to use and then calls HMT_MEDIUM to increase the priority. This feature supports on P7 or later processors. We save/ restore PPR for all exception vectors except system call entry. GLIBC will be saving / restore for system calls. So the default PPR value (3) will be set for the system call exit when the task returned to the user space. Signed-off-by: Haren Myneni Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/exception-64s.h | 18 ++++++++++-------- arch/powerpc/kernel/entry_64.S | 3 +++ arch/powerpc/kernel/exceptions-64s.S | 23 +++++++++++++---------- 3 files changed, 26 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 391e01387248..370298a0bca3 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -147,8 +147,9 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,943) #define __EXCEPTION_PROLOG_1(area, extra, vec) \ GET_PACA(r13); \ - std r9,area+EX_R9(r13); /* save r9 - r12 */ \ - std r10,area+EX_R10(r13); \ + std r9,area+EX_R9(r13); /* save r9 */ \ + HMT_MEDIUM_PPR_SAVE(area, r9); \ + std r10,area+EX_R10(r13); /* save r10 - r12 */ \ BEGIN_FTR_SECTION_NESTED(66); \ mfspr r10,SPRN_CFAR; \ std r10,area+EX_CFAR(r13); \ @@ -264,6 +265,7 @@ do_kvm_##n: \ std r10,GPR1(r1); /* save r1 in stackframe */ \ beq 4f; /* if from kernel mode */ \ ACCOUNT_CPU_USER_ENTRY(r9, r10); \ + SAVE_PPR(area, r9, r10); \ 4: std r2,GPR2(r1); /* save r2 in stackframe */ \ SAVE_4GPRS(3, r1); /* save r3 - r6 in stackframe */ \ SAVE_2GPRS(7, r1); /* save r7, r8 in stackframe */ \ @@ -305,7 +307,7 @@ do_kvm_##n: \ . = loc; \ .globl label##_pSeries; \ label##_pSeries: \ - HMT_MEDIUM; \ + HMT_MEDIUM_PPR_DISCARD; \ SET_SCRATCH0(r13); /* save r13 */ \ EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common, \ EXC_STD, KVMTEST_PR, vec) @@ -314,7 +316,7 @@ label##_pSeries: \ . = loc; \ .globl label##_hv; \ label##_hv: \ - HMT_MEDIUM; \ + HMT_MEDIUM_PPR_DISCARD; \ SET_SCRATCH0(r13); /* save r13 */ \ EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common, \ EXC_HV, KVMTEST, vec) @@ -323,7 +325,7 @@ label##_hv: \ . = loc; \ .globl label##_relon_pSeries; \ label##_relon_pSeries: \ - HMT_MEDIUM; \ + HMT_MEDIUM_PPR_DISCARD; \ /* No guest interrupts come through here */ \ SET_SCRATCH0(r13); /* save r13 */ \ EXCEPTION_RELON_PROLOG_PSERIES(PACA_EXGEN, label##_common, \ @@ -333,7 +335,7 @@ label##_relon_pSeries: \ . = loc; \ .globl label##_relon_hv; \ label##_relon_hv: \ - HMT_MEDIUM; \ + HMT_MEDIUM_PPR_DISCARD; \ /* No guest interrupts come through here */ \ SET_SCRATCH0(r13); /* save r13 */ \ EXCEPTION_RELON_PROLOG_PSERIES(PACA_EXGEN, label##_common, \ @@ -371,7 +373,7 @@ label##_relon_hv: \ #define SOFTEN_NOTEST_HV(vec) _SOFTEN_TEST(EXC_HV, vec) #define __MASKABLE_EXCEPTION_PSERIES(vec, label, h, extra) \ - HMT_MEDIUM; \ + HMT_MEDIUM_PPR_DISCARD; \ SET_SCRATCH0(r13); /* save r13 */ \ __EXCEPTION_PROLOG_1(PACA_EXGEN, extra, vec); \ EXCEPTION_PROLOG_PSERIES_1(label##_common, h); @@ -393,7 +395,7 @@ label##_hv: \ EXC_HV, SOFTEN_TEST_HV) #define __MASKABLE_RELON_EXCEPTION_PSERIES(vec, label, h, extra) \ - HMT_MEDIUM; \ + HMT_MEDIUM_PPR_DISCARD; \ SET_SCRATCH0(r13); /* save r13 */ \ __EXCEPTION_PROLOG_1(PACA_EXGEN, extra, vec); \ EXCEPTION_RELON_PROLOG_PSERIES_1(label##_common, h); diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 7a70d0a6df3e..6faf51e165a5 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -227,6 +227,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) beq- 1f ACCOUNT_CPU_USER_EXIT(r11, r12) + HMT_MEDIUM_LOW_HAS_PPR ld r13,GPR13(r1) /* only restore r13 if returning to usermode */ 1: ld r2,GPR2(r1) ld r1,GPR1(r1) @@ -303,6 +304,7 @@ syscall_exit_work: subi r12,r12,TI_FLAGS 4: /* Anything else left to do? */ + SET_DEFAULT_THREAD_PPR(r3, r9) /* Set thread.ppr = 3 */ andi. r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SINGLESTEP) beq .ret_from_except_lite @@ -758,6 +760,7 @@ fast_exception_return: andi. r0,r3,MSR_PR beq 1f ACCOUNT_CPU_USER_EXIT(r2, r4) + RESTORE_PPR(r2, r4) REST_GPR(13, r1) 1: mtspr SPRN_SRR1,r3 diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 32fc04f78890..3425aba8da51 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -104,7 +104,7 @@ __start_interrupts: .globl system_reset_pSeries; system_reset_pSeries: - HMT_MEDIUM; + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) #ifdef CONFIG_PPC_P7_NAP BEGIN_FTR_SECTION @@ -158,7 +158,7 @@ machine_check_pSeries_1: . = 0x300 .globl data_access_pSeries data_access_pSeries: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) BEGIN_FTR_SECTION b data_access_check_stab @@ -170,7 +170,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_SLB) . = 0x380 .globl data_access_slb_pSeries data_access_slb_pSeries: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST, 0x380) std r3,PACA_EXSLB+EX_R3(r13) @@ -201,7 +201,7 @@ data_access_slb_pSeries: . = 0x480 .globl instruction_access_slb_pSeries instruction_access_slb_pSeries: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x480) std r3,PACA_EXSLB+EX_R3(r13) @@ -324,10 +324,11 @@ vsx_unavailable_pSeries_1: . = 0x1500 .global denorm_exception_hv denorm_exception_hv: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD mtspr SPRN_SPRG_HSCRATCH0,r13 mfspr r13,SPRN_SPRG_HPACA std r9,PACA_EXGEN+EX_R9(r13) + HMT_MEDIUM_PPR_SAVE(PACA_EXGEN, r9) std r10,PACA_EXGEN+EX_R10(r13) std r11,PACA_EXGEN+EX_R11(r13) std r12,PACA_EXGEN+EX_R12(r13) @@ -369,7 +370,7 @@ denorm_exception_hv: machine_check_pSeries: .globl machine_check_fwnmi machine_check_fwnmi: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) /* save r13 */ EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common, EXC_STD, KVMTEST, 0x200) @@ -498,6 +499,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206) mtspr SPRN_HSRR0,r11 mtcrf 0x80,r9 ld r9,PACA_EXGEN+EX_R9(r13) + RESTORE_PPR_PACA(PACA_EXGEN, r10) ld r10,PACA_EXGEN+EX_R10(r13) ld r11,PACA_EXGEN+EX_R11(r13) ld r12,PACA_EXGEN+EX_R12(r13) @@ -603,7 +605,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE) .globl system_reset_fwnmi .align 7 system_reset_fwnmi: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) /* save r13 */ EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common, EXC_STD, NOTEST, 0x100) @@ -716,7 +718,7 @@ machine_check_common: . = 0x4380 .globl data_access_slb_relon_pSeries data_access_slb_relon_pSeries: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x380) std r3,PACA_EXSLB+EX_R3(r13) @@ -741,7 +743,7 @@ data_access_slb_relon_pSeries: . = 0x4480 .globl instruction_access_slb_relon_pSeries instruction_access_slb_relon_pSeries: - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x480) std r3,PACA_EXSLB+EX_R3(r13) @@ -1062,6 +1064,7 @@ _GLOBAL(slb_miss_realmode) mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */ .machine pop + RESTORE_PPR_PACA(PACA_EXSLB, r9) ld r9,PACA_EXSLB+EX_R9(r13) ld r10,PACA_EXSLB+EX_R10(r13) ld r11,PACA_EXSLB+EX_R11(r13) @@ -1411,7 +1414,7 @@ initial_stab: #ifdef CONFIG_PPC_POWERNV _GLOBAL(opal_mc_secondary_handler) - HMT_MEDIUM + HMT_MEDIUM_PPR_DISCARD SET_SCRATCH0(r13) GET_PACA(r13) clrldi r3,r3,2 -- 2.20.1