From 9d378dfac885f72b8b369d08fc61bef36e2f2dd1 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Mon, 10 Mar 2014 17:29:38 -0500 Subject: [PATCH] powerpc/booke64: Use SPRG7 for VDSO Previously SPRG3 was marked for use by both VDSO and critical interrupts (though critical interrupts were not fully implemented). In commit 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad ("powerpc/booke64: Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman made an attempt to resolve this conflict by restoring the VDSO value early in the critical interrupt, but this has some issues: - It's incompatible with EXCEPTION_COMMON which restores r13 from the by-then-overwritten scratch (this cost me some debugging time). - It forces critical exceptions to be a special case handled differently from even machine check and debug level exceptions. - It didn't occur to me that it was possible to make this work at all (by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after I made (most of) this patch. :-) It might be worth investigating using a load rather than SPRG on return from all exceptions (except TLB misses where the scratch never leaves the SPRG) -- it could save a few cycles. Until then, let's stick with SPRG for all exceptions. Since we cannot use SPRG4-7 for scratch without corrupting the state of a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor critical interrupts exist on book3s, SPRG3 is still used for VDSO there. Signed-off-by: Scott Wood Cc: Mihai Caraman Cc: Anton Blanchard Cc: Paul Mackerras Cc: kvm-ppc@vger.kernel.org --- arch/powerpc/include/asm/exception-64e.h | 5 ++--- arch/powerpc/include/asm/kvm_booke_hv_asm.h | 9 +-------- arch/powerpc/include/asm/paca.h | 2 +- arch/powerpc/include/asm/reg.h | 13 ++++++++++--- arch/powerpc/kernel/asm-offsets.c | 2 +- arch/powerpc/kernel/exceptions-64e.S | 19 ++----------------- arch/powerpc/kernel/vdso.c | 8 ++++---- arch/powerpc/kernel/vdso32/getcpu.S | 2 +- arch/powerpc/kernel/vdso64/getcpu.S | 2 +- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 4 ++-- arch/powerpc/kvm/book3s_interrupts.S | 4 ++-- arch/powerpc/kvm/bookehv_interrupts.S | 10 ++++++---- 12 files changed, 33 insertions(+), 47 deletions(-) diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h index 51fa43e536b9..e73452f09019 100644 --- a/arch/powerpc/include/asm/exception-64e.h +++ b/arch/powerpc/include/asm/exception-64e.h @@ -46,9 +46,8 @@ #define EX_CR (1 * 8) #define EX_R10 (2 * 8) #define EX_R11 (3 * 8) -#define EX_R13 (4 * 8) -#define EX_R14 (5 * 8) -#define EX_R15 (6 * 8) +#define EX_R14 (4 * 8) +#define EX_R15 (5 * 8) /* * The TLB miss exception uses different slots. diff --git a/arch/powerpc/include/asm/kvm_booke_hv_asm.h b/arch/powerpc/include/asm/kvm_booke_hv_asm.h index 3a79f5325712..c3e3fd53a3a9 100644 --- a/arch/powerpc/include/asm/kvm_booke_hv_asm.h +++ b/arch/powerpc/include/asm/kvm_booke_hv_asm.h @@ -36,19 +36,12 @@ * *(r8 + GPR11) = saved r11 * * 64-bit host - * Expected inputs (GEN/GDBELL/DBG/MC exception types): + * Expected inputs (GEN/GDBELL/DBG/CRIT/MC exception types): * r10 = saved CR * r13 = PACA_POINTER * *(r13 + PACA_EX##type + EX_R10) = saved r10 * *(r13 + PACA_EX##type + EX_R11) = saved r11 * SPRN_SPRG_##type##_SCRATCH = saved r13 - * - * Expected inputs (CRIT exception type): - * r10 = saved CR - * r13 = PACA_POINTER - * *(r13 + PACA_EX##type + EX_R10) = saved r10 - * *(r13 + PACA_EX##type + EX_R11) = saved r11 - * *(r13 + PACA_EX##type + EX_R13) = saved r13 * * Expected inputs (TLB exception type): * r10 = saved CR diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 9c5dbc3833fb..948f01a04cc3 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -146,7 +146,7 @@ struct paca_struct { u8 io_sync; /* writel() needs spin_unlock sync */ u8 irq_work_pending; /* IRQ_WORK interrupt while soft-disable */ u8 nap_state_lost; /* NV GPR values lost in power7_idle */ - u64 sprg3; /* Saved user-visible sprg */ + u64 sprg_vdso; /* Saved user-visible sprg */ #ifdef CONFIG_PPC_TRANSACTIONAL_MEM u64 tm_scratch; /* TM scratch area for reclaim */ #endif diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index bf0fb4db0855..f7251c2dc049 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -577,9 +577,13 @@ #define SPRN_SPRG3 0x113 /* Special Purpose Register General 3 */ #define SPRN_USPRG3 0x103 /* SPRG3 userspace read */ #define SPRN_SPRG4 0x114 /* Special Purpose Register General 4 */ +#define SPRN_USPRG4 0x104 /* SPRG4 userspace read */ #define SPRN_SPRG5 0x115 /* Special Purpose Register General 5 */ +#define SPRN_USPRG5 0x105 /* SPRG5 userspace read */ #define SPRN_SPRG6 0x116 /* Special Purpose Register General 6 */ +#define SPRN_USPRG6 0x106 /* SPRG6 userspace read */ #define SPRN_SPRG7 0x117 /* Special Purpose Register General 7 */ +#define SPRN_USPRG7 0x107 /* SPRG7 userspace read */ #define SPRN_SRR0 0x01A /* Save/Restore Register 0 */ #define SPRN_SRR1 0x01B /* Save/Restore Register 1 */ #define SRR1_ISI_NOPT 0x40000000 /* ISI: Not found in hash */ @@ -879,11 +883,10 @@ * 64-bit embedded * - SPRG0 generic exception scratch * - SPRG2 TLB exception stack - * - SPRG3 critical exception scratch and - * CPU and NUMA node for VDSO getcpu (user visible) + * - SPRG3 critical exception scratch (user visible, sorry!) * - SPRG4 unused (user visible) * - SPRG6 TLB miss scratch (user visible, sorry !) - * - SPRG7 critical exception scratch + * - SPRG7 CPU and NUMA node for VDSO getcpu (user visible) * - SPRG8 machine check exception scratch * - SPRG9 debug exception scratch * @@ -940,6 +943,8 @@ #define SPRN_SPRG_SCRATCH0 SPRN_SPRG2 #define SPRN_SPRG_HPACA SPRN_HSPRG0 #define SPRN_SPRG_HSCRATCH0 SPRN_HSPRG1 +#define SPRN_SPRG_VDSO_READ SPRN_USPRG3 +#define SPRN_SPRG_VDSO_WRITE SPRN_SPRG3 #define GET_PACA(rX) \ BEGIN_FTR_SECTION_NESTED(66); \ @@ -983,6 +988,8 @@ #define SPRN_SPRG_TLB_SCRATCH SPRN_SPRG6 #define SPRN_SPRG_GEN_SCRATCH SPRN_SPRG0 #define SPRN_SPRG_GDBELL_SCRATCH SPRN_SPRG_GEN_SCRATCH +#define SPRN_SPRG_VDSO_READ SPRN_USPRG7 +#define SPRN_SPRG_VDSO_WRITE SPRN_SPRG7 #define SET_PACA(rX) mtspr SPRN_SPRG_PACA,rX #define GET_PACA(rX) mfspr rX,SPRN_SPRG_PACA diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index b5aacf72ae6f..dba8140ebc20 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -253,7 +253,7 @@ int main(void) DEFINE(PACA_SYSTEM_TIME, offsetof(struct paca_struct, system_time)); DEFINE(PACA_TRAP_SAVE, offsetof(struct paca_struct, trap_save)); DEFINE(PACA_NAPSTATELOST, offsetof(struct paca_struct, nap_state_lost)); - DEFINE(PACA_SPRG3, offsetof(struct paca_struct, sprg3)); + DEFINE(PACA_SPRG_VDSO, offsetof(struct paca_struct, sprg_vdso)); #endif /* CONFIG_PPC64 */ /* RTAS */ diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index 41380a424108..89e1133b0185 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -55,7 +55,6 @@ mfspr r13,SPRN_SPRG_PACA; /* get PACA */ \ std r10,PACA_EX##type+EX_R10(r13); \ std r11,PACA_EX##type+EX_R11(r13); \ - PROLOG_STORE_RESTORE_SCRATCH_##type; \ mfcr r10; /* save CR */ \ mfspr r11,SPRN_##type##_SRR1;/* what are we coming from */ \ DO_KVM intnum,SPRN_##type##_SRR1; /* KVM hook */ \ @@ -116,20 +115,6 @@ #define GDBELL_EXCEPTION_PROLOG(n, intnum, addition) \ EXCEPTION_PROLOG(n, intnum, GDBELL, addition##_GDBELL(n)) -/* - * Store user-visible scratch in PACA exception slots and restore proper value - */ -#define PROLOG_STORE_RESTORE_SCRATCH_GEN -#define PROLOG_STORE_RESTORE_SCRATCH_GDBELL -#define PROLOG_STORE_RESTORE_SCRATCH_DBG -#define PROLOG_STORE_RESTORE_SCRATCH_MC - -#define PROLOG_STORE_RESTORE_SCRATCH_CRIT \ - mfspr r10,SPRN_SPRG_CRIT_SCRATCH; /* get r13 */ \ - std r10,PACA_EXCRIT+EX_R13(r13); \ - ld r11,PACA_SPRG3(r13); \ - mtspr SPRN_SPRG_CRIT_SCRATCH,r11; - /* Variants of the "addition" argument for the prolog */ #define PROLOG_ADDITION_NONE_GEN(n) @@ -529,7 +514,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) mtcr r10 ld r10,PACA_EXCRIT+EX_R10(r13) /* restore registers */ ld r11,PACA_EXCRIT+EX_R11(r13) - ld r13,PACA_EXCRIT+EX_R13(r13) + mfspr r13,SPRN_SPRG_CRIT_SCRATCH rfci /* Normal debug exception */ @@ -542,7 +527,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) /* Now we mash up things to make it look like we are coming on a * normal exception */ - ld r15,PACA_EXCRIT+EX_R13(r13) + mfspr r15,SPRN_SPRG_CRIT_SCRATCH mtspr SPRN_SPRG_GEN_SCRATCH,r15 mfspr r14,SPRN_DBSR EXCEPTION_COMMON(0xd00, PACA_EXCRIT, INTS_DISABLE) diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 094e45c16a17..ce74c335a6a4 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -715,8 +715,8 @@ int vdso_getcpu_init(void) unsigned long cpu, node, val; /* - * SPRG3 contains the CPU in the bottom 16 bits and the NUMA node in - * the next 16 bits. The VDSO uses this to implement getcpu(). + * SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node + * in the next 16 bits. The VDSO uses this to implement getcpu(). */ cpu = get_cpu(); WARN_ON_ONCE(cpu > 0xffff); @@ -725,8 +725,8 @@ int vdso_getcpu_init(void) WARN_ON_ONCE(node > 0xffff); val = (cpu & 0xfff) | ((node & 0xffff) << 16); - mtspr(SPRN_SPRG3, val); - get_paca()->sprg3 = val; + mtspr(SPRN_SPRG_VDSO_WRITE, val); + get_paca()->sprg_vdso = val; put_cpu(); diff --git a/arch/powerpc/kernel/vdso32/getcpu.S b/arch/powerpc/kernel/vdso32/getcpu.S index 47afd08c90f7..23eb9a9441bd 100644 --- a/arch/powerpc/kernel/vdso32/getcpu.S +++ b/arch/powerpc/kernel/vdso32/getcpu.S @@ -29,7 +29,7 @@ */ V_FUNCTION_BEGIN(__kernel_getcpu) .cfi_startproc - mfspr r5,SPRN_USPRG3 + mfspr r5,SPRN_SPRG_VDSO_READ cmpdi cr0,r3,0 cmpdi cr1,r4,0 clrlwi r6,r5,16 diff --git a/arch/powerpc/kernel/vdso64/getcpu.S b/arch/powerpc/kernel/vdso64/getcpu.S index 47afd08c90f7..23eb9a9441bd 100644 --- a/arch/powerpc/kernel/vdso64/getcpu.S +++ b/arch/powerpc/kernel/vdso64/getcpu.S @@ -29,7 +29,7 @@ */ V_FUNCTION_BEGIN(__kernel_getcpu) .cfi_startproc - mfspr r5,SPRN_USPRG3 + mfspr r5,SPRN_SPRG_VDSO_READ cmpdi cr0,r3,0 cmpdi cr1,r4,0 clrlwi r6,r5,16 diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index e66d4ec04d95..fbfca5778b0b 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -75,8 +75,8 @@ BEGIN_FTR_SECTION END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) /* Restore SPRG3 */ - ld r3,PACA_SPRG3(r13) - mtspr SPRN_SPRG3,r3 + ld r3,PACA_SPRG_VDSO(r13) + mtspr SPRN_SPRG_VDSO_WRITE,r3 /* Reload the host's PMU registers */ ld r3, PACALPPACAPTR(r13) /* is the host using the PMU? */ diff --git a/arch/powerpc/kvm/book3s_interrupts.S b/arch/powerpc/kvm/book3s_interrupts.S index f779450cb07c..3533c999194a 100644 --- a/arch/powerpc/kvm/book3s_interrupts.S +++ b/arch/powerpc/kvm/book3s_interrupts.S @@ -153,8 +153,8 @@ kvm_start_lightweight: * Reload kernel SPRG3 value. * No need to save guest value as usermode can't modify SPRG3. */ - ld r3, PACA_SPRG3(r13) - mtspr SPRN_SPRG3, r3 + ld r3, PACA_SPRG_VDSO(r13) + mtspr SPRN_SPRG_VDSO_WRITE, r3 #endif /* CONFIG_PPC_BOOK3S_64 */ /* R7 = vcpu */ diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S index e4185f6b3309..99635a37c78c 100644 --- a/arch/powerpc/kvm/bookehv_interrupts.S +++ b/arch/powerpc/kvm/bookehv_interrupts.S @@ -229,11 +229,7 @@ stw r10, VCPU_CR(r4) PPC_STL r11, VCPU_GPR(R4)(r4) PPC_STL r5, VCPU_GPR(R5)(r4) - .if \type == EX_CRIT - PPC_LL r5, (\paca_ex + EX_R13)(r13) - .else mfspr r5, \scratch - .endif PPC_STL r6, VCPU_GPR(R6)(r4) PPC_STL r8, VCPU_GPR(R8)(r4) PPC_STL r9, VCPU_GPR(R9)(r4) @@ -435,10 +431,16 @@ _GLOBAL(kvmppc_resume_host) PPC_STL r5, VCPU_LR(r4) mfspr r7, SPRN_SPRG5 stw r3, VCPU_VRSAVE(r4) +#ifdef CONFIG_64BIT + PPC_LL r3, PACA_SPRG_VDSO(r13) +#endif PPC_STD(r6, VCPU_SHARED_SPRG4, r11) mfspr r8, SPRN_SPRG6 PPC_STD(r7, VCPU_SHARED_SPRG5, r11) mfspr r9, SPRN_SPRG7 +#ifdef CONFIG_64BIT + mtspr SPRN_SPRG_VDSO_WRITE, r3 +#endif PPC_STD(r8, VCPU_SHARED_SPRG6, r11) mfxer r3 PPC_STD(r9, VCPU_SHARED_SPRG7, r11)