[PATCH v2 05/13] perf: Force architectures to opt-in to guest callbacks
From: Sean Christopherson <seanjc@google.com>
Date: 2021-08-28 00:37:15
Also in:
kvm, kvmarm, linux-arm-kernel, linux-perf-users, lkml, xen-devel
Subsystem:
arm pmu profiling and debugging, arm port, arm64 port (aarch64 architecture), c-sky architecture, performance events subsystem, risc-v architecture, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Will Deacon, Mark Rutland, Russell King, Catalin Marinas, Guo Ren, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds, Thomas Gleixner, Borislav Petkov, Dave Hansen
Introduce HAVE_GUEST_PERF_EVENTS and require architectures to select it to allow registering guest callbacks in perf. Future patches will convert the callbacks to static_call. Rather than churn a bunch of arch code (that was presumably copy+pasted from x86), remove it wholesale as it's useless and at best wasting cycles. Wrap even the stubs with an #ifdef to avoid an arch sneaking in a bogus registration with CONFIG_PERF_EVENTS=n. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/arm/kernel/perf_callchain.c | 33 ++++------------------------- arch/arm64/Kconfig | 1 + arch/csky/kernel/perf_callchain.c | 12 ----------- arch/nds32/kernel/perf_event_cpu.c | 34 ++++-------------------------- arch/riscv/kernel/perf_callchain.c | 13 ------------ arch/x86/Kconfig | 1 + include/linux/perf_event.h | 4 ++++ init/Kconfig | 3 +++ kernel/events/core.c | 2 ++ 9 files changed, 19 insertions(+), 84 deletions(-)
diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c
index 1626dfc6f6ce..bc6b246ab55e 100644
--- a/arch/arm/kernel/perf_callchain.c
+++ b/arch/arm/kernel/perf_callchain.c@@ -62,14 +62,8 @@ user_backtrace(struct frame_tail __user *tail, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct frame_tail __user *tail; - if (guest_cbs && guest_cbs->is_in_guest()) { - /* We don't support guest os callchain now */ - return; - } - perf_callchain_store(entry, regs->ARM_pc); if (!current->mm)
@@ -99,44 +93,25 @@ callchain_trace(struct stackframe *fr, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (guest_cbs && guest_cbs->is_in_guest()) { - /* We don't support guest os callchain now */ - return; - } - arm_get_current_stackframe(regs, &fr); walk_stackframe(&fr, callchain_trace, entry); } unsigned long perf_instruction_pointer(struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); - - if (guest_cbs && guest_cbs->is_in_guest()) - return guest_cbs->get_guest_ip(); - return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - if (guest_cbs && guest_cbs->is_in_guest()) { - if (guest_cbs->is_user_mode()) - misc |= PERF_RECORD_MISC_GUEST_USER; - else - misc |= PERF_RECORD_MISC_GUEST_KERNEL; - } else { - if (user_mode(regs)) - misc |= PERF_RECORD_MISC_USER; - else - misc |= PERF_RECORD_MISC_KERNEL; - } + if (user_mode(regs)) + misc |= PERF_RECORD_MISC_USER; + else + misc |= PERF_RECORD_MISC_KERNEL; return misc; }
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b5b13a932561..72a201a686c5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -190,6 +190,7 @@ config ARM64 select HAVE_NMI select HAVE_PATA_PLATFORM select HAVE_PERF_EVENTS + select HAVE_GUEST_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP select HAVE_REGS_AND_STACK_ACCESS_API
diff --git a/arch/csky/kernel/perf_callchain.c b/arch/csky/kernel/perf_callchain.c
index 35318a635a5f..92057de08f4f 100644
--- a/arch/csky/kernel/perf_callchain.c
+++ b/arch/csky/kernel/perf_callchain.c@@ -86,13 +86,8 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; - /* C-SKY does not support virtualization. */ - if (guest_cbs && guest_cbs->is_in_guest()) - return; - fp = regs->regs[4]; perf_callchain_store(entry, regs->pc);
@@ -111,15 +106,8 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - /* C-SKY does not support virtualization. */ - if (guest_cbs && guest_cbs->is_in_guest()) { - pr_warn("C-SKY does not support perf in guest mode!"); - return; - } - fr.fp = regs->regs[4]; fr.lr = regs->lr; walk_stackframe(&fr, entry);
diff --git a/arch/nds32/kernel/perf_event_cpu.c b/arch/nds32/kernel/perf_event_cpu.c
index f38791960781..a78a879e7ef1 100644
--- a/arch/nds32/kernel/perf_event_cpu.c
+++ b/arch/nds32/kernel/perf_event_cpu.c@@ -1363,7 +1363,6 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; unsigned long gp = 0; unsigned long lp = 0;
@@ -1372,11 +1371,6 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, leaf_fp = 0; - if (guest_cbs && guest_cbs->is_in_guest()) { - /* We don't support guest os callchain now */ - return; - } - perf_callchain_store(entry, regs->ipc); fp = regs->fp; gp = regs->gp;
@@ -1480,13 +1474,8 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); struct stackframe fr; - if (guest_cbs && guest_cbs->is_in_guest()) { - /* We don't support guest os callchain now */ - return; - } fr.fp = regs->fp; fr.lp = regs->lp; fr.sp = regs->sp;
@@ -1495,32 +1484,17 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, unsigned long perf_instruction_pointer(struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); - - /* However, NDS32 does not support virtualization */ - if (guest_cbs && guest_cbs->is_in_guest()) - return guest_cbs->get_guest_ip(); - return instruction_pointer(regs); } unsigned long perf_misc_flags(struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); int misc = 0; - /* However, NDS32 does not support virtualization */ - if (guest_cbs && guest_cbs->is_in_guest()) { - if (guest_cbs->is_user_mode()) - misc |= PERF_RECORD_MISC_GUEST_USER; - else - misc |= PERF_RECORD_MISC_GUEST_KERNEL; - } else { - if (user_mode(regs)) - misc |= PERF_RECORD_MISC_USER; - else - misc |= PERF_RECORD_MISC_KERNEL; - } + if (user_mode(regs)) + misc |= PERF_RECORD_MISC_USER; + else + misc |= PERF_RECORD_MISC_KERNEL; return misc; }
diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c
index 8ecfc4c128bc..1fc075b8f764 100644
--- a/arch/riscv/kernel/perf_callchain.c
+++ b/arch/riscv/kernel/perf_callchain.c@@ -56,13 +56,8 @@ static unsigned long user_backtrace(struct perf_callchain_entry_ctx *entry, void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); unsigned long fp = 0; - /* RISC-V does not support perf in guest mode. */ - if (guest_cbs && guest_cbs->is_in_guest()) - return; - fp = regs->s0; perf_callchain_store(entry, regs->epc);
@@ -79,13 +74,5 @@ static bool fill_callchain(void *entry, unsigned long pc) void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { - struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs(); - - /* RISC-V does not support perf in guest mode. */ - if (guest_cbs && guest_cbs->is_in_guest()) { - pr_warn("RISC-V does not support perf in guest mode!"); - return; - } - walk_stackframe(NULL, regs, fill_callchain, entry); }
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 49270655e827..a4de4aa7a3df 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig@@ -229,6 +229,7 @@ config X86 select HAVE_PERF_EVENTS select HAVE_PERF_EVENTS_NMI select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI + select HAVE_GUEST_PERF_EVENTS select HAVE_PCI select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2b77e2154b61..e75971f85cc8 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h@@ -1236,6 +1236,7 @@ extern void perf_event_bpf_event(struct bpf_prog *prog, enum perf_bpf_event_type type, u16 flags); +#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS extern struct perf_guest_info_callbacks *perf_guest_cbs; static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) {
@@ -1247,6 +1248,7 @@ static inline struct perf_guest_info_callbacks *perf_get_guest_cbs(void) } extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); extern void perf_unregister_guest_info_callbacks(void); +#endif /* CONFIG_HAVE_GUEST_PERF_EVENTS */ extern void perf_event_exec(void); extern void perf_event_comm(struct task_struct *tsk, bool exec);
@@ -1489,9 +1491,11 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) { } static inline void perf_bp_event(struct perf_event *event, void *data) { } +#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS static inline void perf_register_guest_info_callbacks (struct perf_guest_info_callbacks *callbacks) { } static inline void perf_unregister_guest_info_callbacks(void) { } +#endif static inline void perf_event_mmap(struct vm_area_struct *vma) { }
diff --git a/init/Kconfig b/init/Kconfig
index 55f9f7738ebb..9ef51ae53977 100644
--- a/init/Kconfig
+++ b/init/Kconfig@@ -1776,6 +1776,9 @@ config HAVE_PERF_EVENTS help See tools/perf/design.txt for details. +config HAVE_GUEST_PERF_EVENTS + bool + config PERF_USE_VMALLOC bool help
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1be95d9ace46..d7f606e06446 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c@@ -6482,6 +6482,7 @@ static void perf_pending_event(struct irq_work *entry) perf_swevent_put_recursion_context(rctx); } +#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS struct perf_guest_info_callbacks *perf_guest_cbs; void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) {
@@ -6499,6 +6500,7 @@ void perf_unregister_guest_info_callbacks(void) synchronize_rcu(); } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); +#endif static void perf_output_sample_regs(struct perf_output_handle *handle,
--
2.33.0.259.gc128427fd7-goog
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