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perf: Drop dead and useless guest "support" from arm, csky, nds32 and riscv 

Drop "support" for guest callbacks from architectures that don't implement
the guest callbacks.  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.

A future patch will also add a Kconfig to force architcture to opt into
the callbacks to make it more difficult for uses "support" to sneak in in
the future.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20211111020738.2512932-6-seanjc@google.com
This commit is contained in:
Sean Christopherson 2021-11-11 02:07:26 +00:00 committed by Peter Zijlstra
parent 2934e3d093
commit 84af21d850
4 changed files with 8 additions and 84 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
arch/arm/kernel/perf_callchain.c
View File

@ -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;
}

12
arch/csky/kernel/perf_callchain.c
View File

@ -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);

34
arch/nds32/kernel/perf_event_cpu.c
View File

@ -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;
}

13
arch/riscv/kernel/perf_callchain.c
View File

@ -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);
}