[PATCH v2 05/13] perf: Force architectures to opt-in to guest callbacks
From: Sean Christopherson
Date: Fri Aug 27 2021 - 20:37:15 EST
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@xxxxxxxxxx>
---
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