Commit 28a27cbd authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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()
parents a15286c6 012669c7

Documentation/trace/kprobes.rst

+5 −19
Original line number Diff line number Diff line
@@ -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

+0 −16
Original line number Diff line number Diff line
@@ -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

+0 −23
Original line number Diff line number Diff line
@@ -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

+0 −17
Original line number Diff line number Diff line
@@ -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

+0 −17
Original line number Diff line number Diff line
@@ -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.