From 54820530c5faa9fd78e1c08cb6449100b1a19157 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Thu, 12 Oct 2017 21:17:18 +1100 Subject: [PATCH] powerpc/powernv: Enable TM without suspend if possible Some Power9 revisions can run in a mode where TM operates without suspended state. If we find ourself on a CPU that might be in this mode, we query OPAL to check, and if so we reenable TM in CPU features, and enable a new user feature to signal to userspace that we are in this mode. We do not enable the "normal" user feature, PPC_FEATURE2_HTM, but we do enable PPC_FEATURE2_HTM_NOSC because that indicates to userspace that the kernel will abort transactions on syscall entry, which is true regardless of the suspend mode. Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/opal-api.h | 2 ++ arch/powerpc/include/asm/powernv.h | 4 ++++ arch/powerpc/include/asm/tm.h | 2 ++ arch/powerpc/kernel/process.c | 7 +++++++ arch/powerpc/kernel/prom.c | 4 ++++ arch/powerpc/platforms/powernv/setup.c | 23 +++++++++++++++++++++++ 6 files changed, 42 insertions(+) diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h index 9d191ebea706..233c7504b1f2 100644 --- a/arch/powerpc/include/asm/opal-api.h +++ b/arch/powerpc/include/asm/opal-api.h @@ -896,6 +896,8 @@ enum { */ OPAL_REINIT_CPUS_MMU_HASH = (1 << 2), OPAL_REINIT_CPUS_MMU_RADIX = (1 << 3), + + OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED = (1 << 4), }; typedef struct oppanel_line { diff --git a/arch/powerpc/include/asm/powernv.h b/arch/powerpc/include/asm/powernv.h index f62797702300..dc5f6a5d4575 100644 --- a/arch/powerpc/include/asm/powernv.h +++ b/arch/powerpc/include/asm/powernv.h @@ -22,6 +22,8 @@ extern void pnv_npu2_destroy_context(struct npu_context *context, extern int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea, unsigned long *flags, unsigned long *status, int count); + +void pnv_tm_init(void); #else static inline void powernv_set_nmmu_ptcr(unsigned long ptcr) { } static inline struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev, @@ -36,6 +38,8 @@ static inline int pnv_npu2_handle_fault(struct npu_context *context, unsigned long *status, int count) { return -ENODEV; } + +static inline void pnv_tm_init(void) { } #endif #endif /* _ASM_POWERNV_H */ diff --git a/arch/powerpc/include/asm/tm.h b/arch/powerpc/include/asm/tm.h index 82e06ca3a49b..ad19fe41931b 100644 --- a/arch/powerpc/include/asm/tm.h +++ b/arch/powerpc/include/asm/tm.h @@ -19,4 +19,6 @@ extern void tm_abort(uint8_t cause); extern void tm_save_sprs(struct thread_struct *thread); extern void tm_restore_sprs(struct thread_struct *thread); +extern bool tm_suspend_disabled; + #endif /* __ASSEMBLY__ */ diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 166145b18728..b02807ea54dc 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -77,6 +77,13 @@ extern unsigned long _get_SP(void); #ifdef CONFIG_PPC_TRANSACTIONAL_MEM +/* + * Are we running in "Suspend disabled" mode? If so we have to block any + * sigreturn that would get us into suspended state, and we also warn in some + * other paths that we should never reach with suspend disabled. + */ +bool tm_suspend_disabled __ro_after_init = false; + static void check_if_tm_restore_required(struct task_struct *tsk) { /* diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index d9bd6555f980..101822be525a 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include #include @@ -681,7 +682,10 @@ static void __init tm_init(void) cur_cpu_spec->cpu_user_features2 &= ~(PPC_FEATURE2_HTM_NOSC | PPC_FEATURE2_HTM); cur_cpu_spec->cpu_features &= ~CPU_FTR_TM; + return; } + + pnv_tm_init(); } #else static void tm_init(void) { } diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c index cf52d53da460..d23f148a11f0 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -36,6 +36,7 @@ #include #include #include +#include #include "powernv.h" @@ -304,6 +305,28 @@ static int __init pnv_probe(void) return 1; } +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM +void __init pnv_tm_init(void) +{ + if (!firmware_has_feature(FW_FEATURE_OPAL) || + !pvr_version_is(PVR_POWER9) || + early_cpu_has_feature(CPU_FTR_TM)) + return; + + if (opal_reinit_cpus(OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED) != OPAL_SUCCESS) + return; + + pr_info("Enabling TM (Transactional Memory) with Suspend Disabled\n"); + cur_cpu_spec->cpu_features |= CPU_FTR_TM; + /* Make sure "normal" HTM is off (it should be) */ + cur_cpu_spec->cpu_user_features2 &= ~PPC_FEATURE2_HTM; + /* Turn on no suspend mode, and HTM no SC */ + cur_cpu_spec->cpu_user_features2 |= PPC_FEATURE2_HTM_NO_SUSPEND | \ + PPC_FEATURE2_HTM_NOSC; + tm_suspend_disabled = true; +} +#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ + /* * Returns the cpu frequency for 'cpu' in Hz. This is used by * /proc/cpuinfo -- 2.39.5