summaryrefslogtreecommitdiffstats
path: root/arch
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-10-30 09:49:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-30 09:49:56 -0700
commit343a9f35409b68b6de66ecd0db90a277aee90ec2 (patch)
tree8f62088c78f3eb9ee1d0dab9f4cee0cf5f3878c6 /arch
parentf4267b3604a84ff72c013a0e3e467289908603a6 (diff)
parenta2acce536921bd793bae13fa344fcea157638e72 (diff)
downloadlinux-343a9f35409b68b6de66ecd0db90a277aee90ec2.tar.bz2
Merge tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt: "The biggest change here is the updates to kprobes Back in January I posted patches to create function based events. These were the events that you suggested I make to allow developers to easily create events in code where no trace event exists. After posting those changes for review, it was suggested that we implement this instead with kprobes. The problem with kprobes is that the interface is too complex and needs to be simplified. Masami Hiramatsu posted patches in March and I've been playing with them a bit. There's been a bit of clean up in the kprobe code that was inspired by the function based event patches, and a couple of enhancements to the kprobe event interface. - If the arch supports it (we added support for x86), you can place a kprobe event at the start of a function and use $arg1, $arg2, etc to reference the arguments of a function. (Before you needed to know what register or where on the stack the argument was). - The second is a way to see array of events. For example, if you reference a mac address, you can add: echo 'p:mac ip_rcv perm_addr=+574($arg2):x8[6]' > kprobe_events And this will produce: mac: (ip_rcv+0x0/0x140) perm_addr={0x52,0x54,0x0,0xc0,0x76,0xec} Other changes include - Exporting trace_dump_stack to modules - Have the stack tracer trace the entire stack (stop trying to remove tracing itself, as we keep removing too much). - Added support for SDT in uprobes" [ SDT - "Statically Defined Tracing" are userspace markers for tracing. Let's not use random TLA's in explanations unless they are fairly well-established as generic (at least for kernel people) - Linus ] * tag 'trace-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (24 commits) tracing: Have stack tracer trace full stack tracing: Export trace_dump_stack to modules tracing: probeevent: Fix uninitialized used of offset in parse args tracing/kprobes: Allow kprobe-events to record module symbol tracing/kprobes: Check the probe on unloaded module correctly tracing/uprobes: Fix to return -EFAULT if copy_from_user failed tracing: probeevent: Add $argN for accessing function args x86: ptrace: Add function argument access API tracing: probeevent: Add array type support tracing: probeevent: Add symbol type tracing: probeevent: Unify fetch_insn processing common part tracing: probeevent: Append traceprobe_ for exported function tracing: probeevent: Return consumed bytes of dynamic area tracing: probeevent: Unify fetch type tables tracing: probeevent: Introduce new argument fetching code tracing: probeevent: Remove NOKPROBE_SYMBOL from print functions tracing: probeevent: Cleanup argument field definition tracing: probeevent: Cleanup print argument functions trace_uprobe: support reference counter in fd-based uprobe perf probe: Support SDT markers having reference counter (semaphore) ...
Diffstat (limited to 'arch')
-rw-r--r--arch/Kconfig7
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/include/asm/ptrace.h38
3 files changed, 46 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 9d329608913e..ed27fd262627 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -290,6 +290,13 @@ config HAVE_RSEQ
This symbol should be selected by an architecture if it
supports an implementation of restartable sequences.
+config HAVE_FUNCTION_ARG_ACCESS_API
+ bool
+ help
+ This symbol should be selected by an architecure if it supports
+ the API needed to access function arguments from pt_regs,
+ declared in asm/ptrace.h
+
config HAVE_CLK
bool
help
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cbd5f28ea8e2..ffebfc3f43c1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -186,6 +186,7 @@ config X86
select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
+ select HAVE_FUNCTION_ARG_ACCESS_API
select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
select HAVE_STACK_VALIDATION if X86_64
select HAVE_RSEQ
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 143c99499531..8a7fc0cca2d1 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -286,6 +286,44 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
return 0;
}
+/**
+ * regs_get_kernel_argument() - get Nth function argument in kernel
+ * @regs: pt_regs of that context
+ * @n: function argument number (start from 0)
+ *
+ * regs_get_argument() returns @n th argument of the function call.
+ * Note that this chooses most probably assignment, in some case
+ * it can be incorrect.
+ * This is expected to be called from kprobes or ftrace with regs
+ * where the top of stack is the return address.
+ */
+static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
+ unsigned int n)
+{
+ static const unsigned int argument_offs[] = {
+#ifdef __i386__
+ offsetof(struct pt_regs, ax),
+ offsetof(struct pt_regs, cx),
+ offsetof(struct pt_regs, dx),
+#define NR_REG_ARGUMENTS 3
+#else
+ offsetof(struct pt_regs, di),
+ offsetof(struct pt_regs, si),
+ offsetof(struct pt_regs, dx),
+ offsetof(struct pt_regs, cx),
+ offsetof(struct pt_regs, r8),
+ offsetof(struct pt_regs, r9),
+#define NR_REG_ARGUMENTS 6
+#endif
+ };
+
+ if (n >= NR_REG_ARGUMENTS) {
+ n -= NR_REG_ARGUMENTS - 1;
+ return regs_get_kernel_stack_nth(regs, n);
+ } else
+ return regs_get_register(regs, argument_offs[n]);
+}
+
#define arch_has_single_step() (1)
#ifdef CONFIG_X86_DEBUGCTLMSR
#define arch_has_block_step() (1)