Merge tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull performance events updates from Ingo Molnar:
 "Callchain support:

   - Add support for deferred user-space stack unwinding for perf,
     enabled on x86. (Peter Zijlstra, Steven Rostedt)

   - unwind_user/x86: Enable frame pointer unwinding on x86 (Josh
     Poimboeuf)

  x86 PMU support and infrastructure:

   - x86/insn: Simplify for_each_insn_prefix() (Peter Zijlstra)

   - x86/insn,uprobes,alternative: Unify insn_is_nop() (Peter Zijlstra)

  Intel PMU driver:

   - Large series to prepare for and implement architectural PEBS
     support for Intel platforms such as Clearwater Forest (CWF) and
     Panther Lake (PTL). (Dapeng Mi, Kan Liang)

   - Check dynamic constraints (Kan Liang)

   - Optimize PEBS extended config (Peter Zijlstra)

   - cstates:
      - Remove PC3 support from LunarLake (Zhang Rui)
      - Add Pantherlake support (Zhang Rui)
      - Clearwater Forest support (Zide Chen)

  AMD PMU driver:

   - x86/amd: Check event before enable to avoid GPF (George Kennedy)

  Fixes and cleanups:

   - task_work: Fix NMI race condition (Peter Zijlstra)

   - perf/x86: Fix NULL event access and potential PEBS record loss
     (Dapeng Mi)

   - Misc other fixes and cleanups (Dapeng Mi, Ingo Molnar, Peter
     Zijlstra)"

* tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
  perf/x86/intel: Fix and clean up intel_pmu_drain_arch_pebs() type use
  perf/x86/intel: Optimize PEBS extended config
  perf/x86/intel: Check PEBS dyn_constraints
  perf/x86/intel: Add a check for dynamic constraints
  perf/x86/intel: Add counter group support for arch-PEBS
  perf/x86/intel: Setup PEBS data configuration and enable legacy groups
  perf/x86/intel: Update dyn_constraint base on PEBS event precise level
  perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR
  perf/x86/intel: Process arch-PEBS records or record fragments
  perf/x86/intel/ds: Factor out PEBS group processing code to functions
  perf/x86/intel/ds: Factor out PEBS record processing code to functions
  perf/x86/intel: Initialize architectural PEBS
  perf/x86/intel: Correct large PEBS flag check
  perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call
  perf/x86: Fix NULL event access and potential PEBS record loss
  perf/x86: Remove redundant is_x86_event() prototype
  entry,unwind/deferred: Fix unwind_reset_info() placement
  unwind_user/x86: Fix arch=um build
  perf: Support deferred user unwind
  unwind_user/x86: Teach FP unwind about start of function
  ...

1 files changed, 48 insertions, 11 deletions

diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 97a8415e3216..39e270789444 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -8,18 +8,28 @@
 #include <linux/unwind_user.h>
 #include <linux/uaccess.h>
 
-static const struct unwind_user_frame fp_frame = {
-	ARCH_INIT_USER_FP_FRAME
-};
-
 #define for_each_user_frame(state) \
 	for (unwind_user_start(state); !(state)->done; unwind_user_next(state))
 
-static int unwind_user_next_fp(struct unwind_user_state *state)
+static inline int
+get_user_word(unsigned long *word, unsigned long base, int off, unsigned int ws)
+{
+	unsigned long __user *addr = (void __user *)base + off;
+#ifdef CONFIG_COMPAT
+	if (ws == sizeof(int)) {
+		unsigned int data;
+		int ret = get_user(data, (unsigned int __user *)addr);
+		*word = data;
+		return ret;
+	}
+#endif
+	return get_user(*word, addr);
+}
+
+static int unwind_user_next_common(struct unwind_user_state *state,
+				   const struct unwind_user_frame *frame)
 {
-	const struct unwind_user_frame *frame = &fp_frame;
 	unsigned long cfa, fp, ra;
-	unsigned int shift;
 
 	if (frame->use_fp) {
 		if (state->fp < state->sp)
@@ -37,24 +47,45 @@ static int unwind_user_next_fp(struct unwind_user_state *state)
 		return -EINVAL;
 
 	/* Make sure that the address is word aligned */
-	shift = sizeof(long) == 4 ? 2 : 3;
-	if (cfa & ((1 << shift) - 1))
+	if (cfa & (state->ws - 1))
 		return -EINVAL;
 
 	/* Find the Return Address (RA) */
-	if (get_user(ra, (unsigned long *)(cfa + frame->ra_off)))
+	if (get_user_word(&ra, cfa, frame->ra_off, state->ws))
 		return -EINVAL;
 
-	if (frame->fp_off && get_user(fp, (unsigned long __user *)(cfa + frame->fp_off)))
+	if (frame->fp_off && get_user_word(&fp, cfa, frame->fp_off, state->ws))
 		return -EINVAL;
 
 	state->ip = ra;
 	state->sp = cfa;
 	if (frame->fp_off)
 		state->fp = fp;
+	state->topmost = false;
 	return 0;
 }
 
+static int unwind_user_next_fp(struct unwind_user_state *state)
+{
+#ifdef CONFIG_HAVE_UNWIND_USER_FP
+	struct pt_regs *regs = task_pt_regs(current);
+
+	if (state->topmost && unwind_user_at_function_start(regs)) {
+		const struct unwind_user_frame fp_entry_frame = {
+			ARCH_INIT_USER_FP_ENTRY_FRAME(state->ws)
+		};
+		return unwind_user_next_common(state, &fp_entry_frame);
+	}
+
+	const struct unwind_user_frame fp_frame = {
+		ARCH_INIT_USER_FP_FRAME(state->ws)
+	};
+	return unwind_user_next_common(state, &fp_frame);
+#else
+	return -EINVAL;
+#endif
+}
+
 static int unwind_user_next(struct unwind_user_state *state)
 {
 	unsigned long iter_mask = state->available_types;
@@ -102,6 +133,12 @@ static int unwind_user_start(struct unwind_user_state *state)
 	state->ip = instruction_pointer(regs);
 	state->sp = user_stack_pointer(regs);
 	state->fp = frame_pointer(regs);
+	state->ws = unwind_user_word_size(regs);
+	if (!state->ws) {
+		state->done = true;
+		return -EINVAL;
+	}
+	state->topmost = true;
 
 	return 0;
 }