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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-04-12 16:48:51 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-23 20:32:25 +1000 |
| commit | 71f6e58e5efe09b98a1862d4c25976e8f7763b67 (patch) | |
| tree | 1f97bd06729dbaa0075b96e434517ca440f559aa /arch/powerpc/lib/code-patching.c | |
| parent | 700e64377c2c8e2406e9c4c1632e2eabdb3a95a1 (diff) | |
| download | lwn-71f6e58e5efe09b98a1862d4c25976e8f7763b67.tar.gz lwn-71f6e58e5efe09b98a1862d4c25976e8f7763b67.zip | |
powerpc/kprobes: Convert __kprobes to NOKPROBE_SYMBOL()
Along similar lines as commit 9326638cbee2 ("kprobes, x86: Use NOKPROBE_SYMBOL()
instead of __kprobes annotation"), convert __kprobes annotation to either
NOKPROBE_SYMBOL() or nokprobe_inline. The latter forces inlining, in which case
the caller needs to be added to NOKPROBE_SYMBOL().
Also:
- blacklist arch_deref_entry_point(), and
- convert a few regular inlines to nokprobe_inline in lib/sstep.c
A key benefit is the ability to detect such symbols as being
blacklisted. Before this patch:
$ cat /sys/kernel/debug/kprobes/blacklist | grep read_mem
$ perf probe read_mem
Failed to write event: Invalid argument
Error: Failed to add events.
$ dmesg | tail -1
[ 3736.112815] Could not insert probe at _text+10014968: -22
After patch:
$ cat /sys/kernel/debug/kprobes/blacklist | grep read_mem
0xc000000000072b50-0xc000000000072d20 read_mem
$ perf probe read_mem
read_mem is blacklisted function, skip it.
Added new events:
(null):(null) (on read_mem)
probe:read_mem (on read_mem)
You can now use it in all perf tools, such as:
perf record -e probe:read_mem -aR sleep 1
$ grep " read_mem" /proc/kallsyms
c000000000072b50 t read_mem
c0000000005f3b40 t read_mem
$ cat /sys/kernel/debug/kprobes/list
c0000000005f3b48 k read_mem+0x8 [DISABLED]
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Minor change log formatting, fix up some conflicts]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/lib/code-patching.c')
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 0d3002b7e2b4..500b0f6a0b64 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -8,6 +8,7 @@ */ #include <linux/kernel.h> +#include <linux/kprobes.h> #include <linux/vmalloc.h> #include <linux/init.h> #include <linux/mm.h> @@ -59,7 +60,7 @@ bool is_offset_in_branch_range(long offset) * Helper to check if a given instruction is a conditional branch * Derived from the conditional checks in analyse_instr() */ -bool __kprobes is_conditional_branch(unsigned int instr) +bool is_conditional_branch(unsigned int instr) { unsigned int opcode = instr >> 26; @@ -75,6 +76,7 @@ bool __kprobes is_conditional_branch(unsigned int instr) } return false; } +NOKPROBE_SYMBOL(is_conditional_branch); unsigned int create_branch(const unsigned int *addr, unsigned long target, int flags) |