[PATCH 04/15] perf: Force architectures to opt-in to guest callbacks
From: Sean Christopherson
Date: Thu Aug 26 2021 - 20:57:46 EST
Introduce HAVE_GUEST_PERF_EVENTS and require architectures to select it
to allow register guest callbacks in perf. Future patches will convert
the callbacks to per-CPU definitions. 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@xxxxxxxxxx>
---
arch/arm/kernel/perf_callchain.c | 28 ++++------------------------
arch/arm64/Kconfig | 1 +
arch/csky/kernel/perf_callchain.c | 10 ----------
arch/nds32/kernel/perf_event_cpu.c | 29 ++++-------------------------
arch/riscv/kernel/perf_callchain.c | 10 ----------
arch/x86/Kconfig | 1 +
include/linux/perf_event.h | 4 ++++
init/Kconfig | 3 +++
kernel/events/core.c | 2 ++
9 files changed, 19 insertions(+), 69 deletions(-)
diff --git a/arch/arm/kernel/perf_callchain.c b/arch/arm/kernel/perf_callchain.c
index 3b69a76d341e..bc6b246ab55e 100644
--- a/arch/arm/kernel/perf_callchain.c
+++ b/arch/arm/kernel/perf_callchain.c
@@ -64,11 +64,6 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs
{
struct frame_tail __user *tail;
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
- /* We don't support guest os callchain now */
- return;
- }
-
perf_callchain_store(entry, regs->ARM_pc);
if (!current->mm)
@@ -100,20 +95,12 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
{
struct stackframe fr;
- if (perf_guest_cbs && perf_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)
{
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
- return perf_guest_cbs->get_guest_ip();
-
return instruction_pointer(regs);
}
@@ -121,17 +108,10 @@ unsigned long perf_misc_flags(struct pt_regs *regs)
{
int misc = 0;
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
- if (perf_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 ab55e98ee8f6..92057de08f4f 100644
--- a/arch/csky/kernel/perf_callchain.c
+++ b/arch/csky/kernel/perf_callchain.c
@@ -88,10 +88,6 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
{
unsigned long fp = 0;
- /* C-SKY does not support virtualization. */
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
- return;
-
fp = regs->regs[4];
perf_callchain_store(entry, regs->pc);
@@ -112,12 +108,6 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
{
struct stackframe fr;
- /* C-SKY does not support virtualization. */
- if (perf_guest_cbs && perf_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 0ce6f9f307e6..a78a879e7ef1 100644
--- a/arch/nds32/kernel/perf_event_cpu.c
+++ b/arch/nds32/kernel/perf_event_cpu.c
@@ -1371,11 +1371,6 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry,
leaf_fp = 0;
- if (perf_guest_cbs && perf_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;
@@ -1481,10 +1476,6 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
{
struct stackframe fr;
- if (perf_guest_cbs && perf_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;
@@ -1493,10 +1484,6 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
- /* However, NDS32 does not support virtualization */
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
- return perf_guest_cbs->get_guest_ip();
-
return instruction_pointer(regs);
}
@@ -1504,18 +1491,10 @@ unsigned long perf_misc_flags(struct pt_regs *regs)
{
int misc = 0;
- /* However, NDS32 does not support virtualization */
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
- if (perf_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 0bb1854dce83..1fc075b8f764 100644
--- a/arch/riscv/kernel/perf_callchain.c
+++ b/arch/riscv/kernel/perf_callchain.c
@@ -58,10 +58,6 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
{
unsigned long fp = 0;
- /* RISC-V does not support perf in guest mode. */
- if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
- return;
-
fp = regs->s0;
perf_callchain_store(entry, regs->epc);
@@ -78,11 +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)
{
- /* RISC-V does not support perf in guest mode. */
- if (perf_guest_cbs && perf_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 05c0efba3cd1..5eab690622ca 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1236,9 +1236,11 @@ 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;
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);
@@ -1481,9 +1483,11 @@ 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 baae796612b9..9820df7ee455 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)
@@ -6495,6 +6496,7 @@ void perf_unregister_guest_info_callbacks(void)
perf_guest_cbs = NULL;
}
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