Merge tag 'perf-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events updates from Ingo Molnar:

 - Platform PMU driver updates:

     - x86 Intel uncore driver updates for Skylake (SNR) and Icelake (ICX) servers
     - Fix RDPMC support
     - Fix [extended-]PEBS-via-PT support
     - Fix Sapphire Rapids event constraints
     - Fix :ppp support on Sapphire Rapids
     - Fix fixed counter sanity check on Alder Lake & X86_FEATURE_HYBRID_CPU
     - Other heterogenous-PMU fixes

 - Kprobes:

     - Remove the unused and misguided kprobe::fault_handler callbacks.
     - Warn about kprobes taking a page fault.
     - Fix the 'nmissed' stat counter.

 - Misc cleanups and fixes.

* tag 'perf-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix task context PMU for Hetero
  perf/x86/intel: Fix instructions:ppp support in Sapphire Rapids
  perf/x86/intel: Add more events requires FRONTEND MSR on Sapphire Rapids
  perf/x86/intel: Fix fixed counter check warning for some Alder Lake
  perf/x86/intel: Fix PEBS-via-PT reload base value for Extended PEBS
  perf/x86: Reset the dirty counter to prevent the leak for an RDPMC task
  kprobes: Do not increment probe miss count in the fault handler
  x86,kprobes: WARN if kprobes tries to handle a fault
  kprobes: Remove kprobe::fault_handler
  uprobes: Update uprobe_write_opcode() kernel-doc comment
  perf/hw_breakpoint: Fix DocBook warnings in perf hw_breakpoint
  perf/core: Fix DocBook warnings
  perf/core: Make local function perf_pmu_snapshot_aux() static
  perf/x86/intel/uncore: Enable I/O stacks to IIO PMON mapping on ICX
  perf/x86/intel/uncore: Enable I/O stacks to IIO PMON mapping on SNR
  perf/x86/intel/uncore: Generalize I/O stacks to PMON mapping procedure
  perf/x86/intel/uncore: Drop unnecessary NULL checks after container_of()

Author: torvalds

Documentation/trace/kprobes.rst

@@ -362,14 +362,11 @@ register_kprobe
 	#include <linux/kprobes.h>
 	int register_kprobe(struct kprobe *kp);
 
-Sets a breakpoint at the address kp->addr.  When the breakpoint is
-hit, Kprobes calls kp->pre_handler.  After the probed instruction
-is single-stepped, Kprobe calls kp->post_handler.  If a fault
-occurs during execution of kp->pre_handler or kp->post_handler,
-or during single-stepping of the probed instruction, Kprobes calls
-kp->fault_handler.  Any or all handlers can be NULL. If kp->flags
-is set KPROBE_FLAG_DISABLED, that kp will be registered but disabled,
-so, its handlers aren't hit until calling enable_kprobe(kp).
+Sets a breakpoint at the address kp->addr.  When the breakpoint is hit, Kprobes
+calls kp->pre_handler.  After the probed instruction is single-stepped, Kprobe
+calls kp->post_handler.  Any or all handlers can be NULL. If kp->flags is set
+KPROBE_FLAG_DISABLED, that kp will be registered but disabled, so, its handlers
+aren't hit until calling enable_kprobe(kp).
 
 .. note::
 
@@ -415,17 +412,6 @@ User's post-handler (kp->post_handler)::
 p and regs are as described for the pre_handler.  flags always seems
 to be zero.
 
-User's fault-handler (kp->fault_handler)::
-
-	#include <linux/kprobes.h>
-	#include <linux/ptrace.h>
-	int fault_handler(struct kprobe *p, struct pt_regs *regs, int trapnr);
-
-p and regs are as described for the pre_handler.  trapnr is the
-architecture-specific trap number associated with the fault (e.g.,
-on i386, 13 for a general protection fault or 14 for a page fault).
-Returns 1 if it successfully handled the exception.
-
 register_kretprobe
 ------------------
 

arch/arc/kernel/kprobes.c

@@ -317,22 +317,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned long trapnr)
 		 * caused the fault.
 		 */
 
-		/* We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-			return 1;
-
 		/*
 		 * In case the user-specified fault handler returned zero,
 		 * try to fix up.

arch/arm/probes/kprobes/core.c

@@ -348,29 +348,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)
 			reset_current_kprobe();
 		}
 		break;
-
-	case KPROBE_HIT_ACTIVE:
-	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, fsr))
-			return 1;
-		break;
-
-	default:
-		break;
 	}
 
 	return 0;

arch/arm64/kernel/probes/kprobes.c

@@ -276,23 +276,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, fsr))
-			return 1;
-
 		/*
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.

arch/csky/kernel/probes/kprobes.c

@@ -294,23 +294,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr)
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-			return 1;
-
 		/*
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.

arch/ia64/kernel/kprobes.c

@@ -843,22 +843,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-			return 1;
 		/*
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.

arch/mips/kernel/kprobes.c

@@ -403,9 +403,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
-	if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-		return 1;
-
 	if (kcb->kprobe_status & KPROBE_HIT_SS) {
 		resume_execution(cur, regs, kcb);
 		regs->cp0_status |= kcb->kprobe_old_SR;

arch/powerpc/kernel/kprobes.c

@@ -501,23 +501,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-			return 1;
-
 		/*
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.

arch/riscv/kernel/probes/kprobes.c

@@ -278,23 +278,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr)
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(cur);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-			return 1;
-
 		/*
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.

arch/s390/kernel/kprobes.c

@@ -445,23 +445,6 @@ static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
 		break;
 	case KPROBE_HIT_ACTIVE:
 	case KPROBE_HIT_SSDONE:
-		/*
-		 * We increment the nmissed count for accounting,
-		 * we can also use npre/npostfault count for accounting
-		 * these specific fault cases.
-		 */
-		kprobes_inc_nmissed_count(p);
-
-		/*
-		 * We come here because instructions in the pre/post
-		 * handler caused the page_fault, this could happen
-		 * if handler tries to access user space by
-		 * copy_from_user(), get_user() etc. Let the
-		 * user-specified handler try to fix it first.
-		 */
-		if (p->fault_handler && p->fault_handler(p, regs, trapnr))
-			return 1;
-
 		/*
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.