linux-toradex.git/include/linux/uprobes.h, branch v4.16-rc4

sparc64:Support User Probes for sparc

2016-12-12T02:01:51+00:00

Signed-off-by: Eric Saint Etienne 
Signed-off-by: Allen Pais 
Signed-off-by: David S. Miller

treewide: Remove old email address

2015-11-23T08:44:58+00:00

There were still a number of references to my old Red Hat email
address in the kernel source. Remove these while keeping the
Red Hat copyright notices intact.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Signed-off-by: Ingo Molnar

uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more clever

2015-07-31T08:38:06+00:00

The previous change documents that cleanup_return_instances()
can't always detect the dead frames, the stack can grow. But
there is one special case which imho worth fixing:
arch_uretprobe_is_alive() can return true when the stack didn't
actually grow, but the next "call" insn uses the already
invalidated frame.

Test-case:

	#include 
	#include 

	jmp_buf jmp;
	int nr = 1024;

	void func_2(void)
	{
		if (--nr == 0)
			return;
		longjmp(jmp, 1);
	}

	void func_1(void)
	{
		setjmp(jmp);
		func_2();
	}

	int main(void)
	{
		func_1();
		return 0;
	}

If you ret-probe func_1() and func_2() prepare_uretprobe() hits
the MAX_URETPROBE_DEPTH limit and "return" from func_2() is not
reported.

When we know that the new call is not chained, we can do the
more strict check. In this case "sp" points to the new ret-addr,
so every frame which uses the same "sp" must be dead. The only
complication is that arch_uretprobe_is_alive() needs to know was
it chained or not, so we add the new RP_CHECK_CHAIN_CALL enum
and change prepare_uretprobe() to pass RP_CHECK_CALL only if
!chained.

Note: arch_uretprobe_is_alive() could also re-read *sp and check
if this word is still trampoline_vaddr. This could obviously
improve the logic, but I would like to avoid another
copy_from_user() especially in the case when we can't avoid the
false "alive == T" positives.

Tested-by: Pratyush Anand 
Signed-off-by: Oleg Nesterov 
Acked-by: Srikar Dronamraju 
Acked-by: Anton Arapov 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20150721134028.GA4786@redhat.com
Signed-off-by: Ingo Molnar

uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive()

2015-07-31T08:38:06+00:00

arch/x86 doesn't care (so far), but as Pratyush Anand pointed
out other architectures might want why arch_uretprobe_is_alive()
was called and use different checks depending on the context.
Add the new argument to distinguish 2 callers.

Tested-by: Pratyush Anand 
Signed-off-by: Oleg Nesterov 
Acked-by: Srikar Dronamraju 
Acked-by: Anton Arapov 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20150721134026.GA4779@redhat.com
Signed-off-by: Ingo Molnar

uprobes/x86: Reimplement arch_uretprobe_is_alive()

2015-07-31T08:38:05+00:00

Add the x86 specific version of arch_uretprobe_is_alive()
helper. It returns true if the stack frame mangled by
prepare_uretprobe() is still on stack. So if it returns false,
we know that the probed function has already returned.

We add the new return_instance->stack member and change the
generic code to initialize it in prepare_uretprobe, but it
should be equally useful for other architectures.

TODO: this assumes that the probed application can't use
      multiple stacks (say sigaltstack). We will try to improve
      this logic later.

Tested-by: Pratyush Anand 
Signed-off-by: Oleg Nesterov 
Acked-by: Srikar Dronamraju 
Acked-by: Anton Arapov 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20150721134018.GA4766@redhat.com
Signed-off-by: Ingo Molnar

uprobes: Export 'struct return_instance', introduce arch_uretprobe_is_alive()

2015-07-31T08:38:04+00:00

Add the new "weak" helper, arch_uretprobe_is_alive(), used by
the next patches. It should return true if this return_instance
is still valid. The arch agnostic version just always returns
true.

The patch exports "struct return_instance" for the architectures
which want to override this hook. We can also cleanup
prepare_uretprobe() if we pass the new return_instance to
arch_uretprobe_hijack_return_addr().

Tested-by: Pratyush Anand 
Signed-off-by: Oleg Nesterov 
Acked-by: Srikar Dronamraju 
Acked-by: Anton Arapov 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20150721134016.GA4762@redhat.com
Signed-off-by: Ingo Molnar

uprobes: Remove "weak" from function declarations

2014-10-22T22:14:04+00:00

For the following interfaces:

  set_swbp()
  set_orig_insn()
  is_swbp_insn()
  is_trap_insn()
  uprobe_get_swbp_addr()
  arch_uprobe_ignore()
  arch_uprobe_copy_ixol()

kernel/events/uprobes.c provides default definitions explicitly marked
"weak".  Some architectures provide their own definitions intended to
override the defaults, but the "weak" attribute on the declarations applied
to the arch definitions as well, so the linker chose one based on link
order (see 10629d711ed7 ("PCI: Remove __weak annotation from
pcibios_get_phb_of_node decl")).

Remove the "weak" attribute from the declarations so we always prefer a
non-weak definition over the weak one, independent of link order.

Signed-off-by: Bjorn Helgaas 
Acked-by: Ingo Molnar 
Acked-by: Srikar Dronamraju 
CC: Victor Kamensky 
CC: Oleg Nesterov 
CC: David A. Long 
CC: Ananth N Mavinakayanahalli

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-06-13T02:18:49+00:00

Pull more perf updates from Ingo Molnar:
 "A second round of perf updates:

   - wide reaching kprobes sanitization and robustization, with the hope
     of fixing all 'probe this function crashes the kernel' bugs, by
     Masami Hiramatsu.

   - uprobes updates from Oleg Nesterov: tmpfs support, corner case
     fixes and robustization work.

   - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
     et al:
        * Add support to accumulate hist periods (Namhyung Kim)
        * various fixes, refactorings and enhancements"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
  perf: Differentiate exec() and non-exec() comm events
  perf: Fix perf_event_comm() vs. exec() assumption
  uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
  perf/documentation: Add description for conditional branch filter
  perf/x86: Add conditional branch filtering support
  perf/tool: Add conditional branch filter 'cond' to perf record
  perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
  uprobes: Teach copy_insn() to support tmpfs
  uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
  perf/x86: Use common PMU interrupt disabled code
  perf/ARM: Use common PMU interrupt disabled code
  perf: Disable sampled events if no PMU interrupt
  perf: Fix use after free in perf_remove_from_context()
  perf tools: Fix 'make help' message error
  perf record: Fix poll return value propagation
  perf tools: Move elide bool into perf_hpp_fmt struct
  perf tools: Remove elide setup for SORT_MODE__MEMORY mode
  perf tools: Fix "==" into "=" in ui_browser__warning assignment
  perf tools: Allow overriding sysfs and proc finding with env var
  perf tools: Consider header files outside perf directory in tags target
  ...

ARM: 8043/1: uprobes need icache flush after xol write

2014-05-25T22:48:45+00:00

After instruction write into xol area, on ARM V7
architecture code need to flush dcache and icache to sync
them up for given set of addresses. Having just
'flush_dcache_page(page)' call is not enough - it is
possible to have stale instruction sitting in icache
for given xol area slot address.

Introduce arch_uprobe_ixol_copy weak function
that by default calls uprobes copy_to_page function and
than flush_dcache_page function and on ARM define new one
that handles xol slot copy in ARM specific way

flush_uprobe_xol_access function shares/reuses implementation
with/of flush_ptrace_access function and takes care of writing
instruction to user land address space on given variety of
different cache types on ARM CPUs. Because
flush_uprobe_xol_access does not have vma around
flush_ptrace_access was split into two parts. First that
retrieves set of condition from vma and common that receives
those conditions as flags.

Note ARM cache flush function need kernel address
through which instruction write happened, so instead
of using uprobes copy_to_page function changed
code to explicitly map page and do memcpy.

Note arch_uprobe_copy_ixol function, in similar way as
copy_to_user_page function, has preempt_disable/preempt_enable.

Signed-off-by: Victor Kamensky 
Acked-by: Oleg Nesterov 
Reviewed-by: David A. Long 
Signed-off-by: Russell King

uprobes/x86: Fix the wrong ->si_addr when xol triggers a trap

2014-05-14T11:57:28+00:00

If the probed insn triggers a trap, ->si_addr = regs->ip is technically
correct, but this is not what the signal handler wants; we need to pass
the address of the probed insn, not the address of xol slot.

Add the new arch-agnostic helper, uprobe_get_trap_addr(), and change
fill_trap_info() and math_error() to use it. !CONFIG_UPROBES case in
uprobes.h uses a macro to avoid include hell and ensure that it can be
compiled even if an architecture doesn't define instruction_pointer().

Test-case:

	#include 
	#include 
	#include 

	extern void probe_div(void);

	void sigh(int sig, siginfo_t *info, void *c)
	{
		int passed = (info->si_addr == probe_div);
		printf(passed ? "PASS\n" : "FAIL\n");
		_exit(!passed);
	}

	int main(void)
	{
		struct sigaction sa = {
			.sa_sigaction	= sigh,
			.sa_flags	= SA_SIGINFO,
		};

		sigaction(SIGFPE, &sa, NULL);

		asm (
			"xor %ecx,%ecx\n"
			".globl probe_div; probe_div:\n"
			"idiv %ecx\n"
		);

		return 0;
	}

it fails if probe_div() is probed.

Note: show_unhandled_signals users should probably use this helper too,
but we need to cleanup them first.

Signed-off-by: Oleg Nesterov 
Reviewed-by: Masami Hiramatsu