Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:
On Thu, Nov 07, 2024 at 07:03:35PM +0000, Colton Lewis wrote:
Break the assignment logic for misc flags into their own respective
functions to reduce the complexity of the nested logic.
Signed-off-by: Colton Lewis <coltonlewis@xxxxxxxxxx>
Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx>
---
arch/x86/events/core.c | 32 +++++++++++++++++++++++--------
arch/x86/include/asm/perf_event.h | 2 ++
2 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index d19e939f3998..9fdc5fa22c66 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -3011,16 +3011,35 @@ unsigned long
perf_arch_instruction_pointer(struct pt_regs *regs)
return regs->ip + code_segment_base(regs);
}
+static unsigned long common_misc_flags(struct pt_regs *regs)
+{
+ if (regs->flags & PERF_EFLAGS_EXACT)
+ return PERF_RECORD_MISC_EXACT_IP;
+
+ return 0;
+}
+
+unsigned long perf_arch_guest_misc_flags(struct pt_regs *regs)
+{
+ unsigned long guest_state = perf_guest_state();
+ unsigned long flags = common_misc_flags(regs);
This is double common_misc and makes no sense
I'm confused what you mean. Are you referring to starting with
common_misc_flags in both perf_arch_misc_flags and
perf_arch_guest_misc_flags so possibly the common_msic_flags are set
twice?
That seems like a good thing that common flags are set wherever they
apply. You can't guarantee where perf_arch_guest_misc_flags may be
called in the future.
+
+ if (!(guest_state & PERF_GUEST_ACTIVE))
+ return flags;
+
+ if (guest_state & PERF_GUEST_USER)
+ return flags & PERF_RECORD_MISC_GUEST_USER;
+ else
+ return flags & PERF_RECORD_MISC_GUEST_KERNEL;
And this is just broken garbage, right?
+}
Did you mean to write:
unsigned long perf_arch_guest_misc_flags(struct pt_regs *regs)
{
unsigned long guest_state = perf_guest_state();
unsigned long flags = 0;
if (guest_state & PERF_GUEST_ACTIVE) {
if (guest_state & PERF_GUEST_USER)
flags |= PERF_RECORD_MISC_GUEST_USER;
else
flags |= PERF_RECORD_MISC_GUEST_KERNEL;
}
return flags;
}
Ok, my mistake was using & instead of |, but the branches are
functionally the same.
I'll use something closer to your suggestion.
unsigned long perf_arch_misc_flags(struct pt_regs *regs)
{
unsigned int guest_state = perf_guest_state();
- int misc = 0;
+ unsigned long misc = common_misc_flags(regs);
Because here you do the common thing..
if (guest_state) {
- if (guest_state & PERF_GUEST_USER)
- misc |= PERF_RECORD_MISC_GUEST_USER;
- else
- misc |= PERF_RECORD_MISC_GUEST_KERNEL;
+ misc |= perf_arch_guest_misc_flags(regs);
And here you mix in the guest things.
} else {
if (user_mode(regs))
misc |= PERF_RECORD_MISC_USER;
