(2013/10/29 15:53), Namhyung Kim wrote: > Hello, > > This patchset implements memory (address), stack[N], deference, > bitfield and retval (it needs uretprobe tho) fetch methods for > uprobes. It's based on the previous work [1] done by Hyeoncheol Lee. > > Now kprobes and uprobes have their own fetch_type_tables and, in turn, > memory and stack access methods. Other fetch methods are shared. > > For the dereference method, I added a new argument to fetch functions. > It's because for uprobes it needs to know whether the given address is > a file offset or a virtual address in an user process. For instance, > in case of fetching from a memory directly (like @offset) it should > convert the address (offset) to a virtual address of the process, but > if it's a dereferencing, the given address already has the virtual > address. > > To determine this in a fetch function, I passed a pointer to > trace_uprobe for direct fetch, and passed NULL for dereference. > > The patch 1-2 are bug fixes and can be applied independently.
You'd better add [BUGFIX] and send those separately. ;) But anyway, I'm OK to pull those first two (and others too). > Please look at patch 10 that uses per-cpu buffer for accessing user > memory as suggested by Steven. While I tried hard not to mess things > up there might be a chance I did something horrible. It'd be great if > you guys take a look and give comments. > > > * v6 changes: > - add more Ack's from Masami > - fix ref count of uprobe_cpu_buffer (thanks to Jovi) > > * v5 changes: > - use user_stack_pointer() instead of GET_USP() > - fix a bug in 'stack' fetch method of uprobes > > * v4 changes: > - add Ack's from Masami > - rearrange patches to make it easy for simple fixes to be applied > - update documentation > - use per-cpu buffer for storing args (thanks to Steve!) > > > [1] https://lkml.org/lkml/2012/11/14/84 > > A simple example: > > # cat foo.c > int glob = -1; > char str[] = "hello uprobe."; > > struct foo { > unsigned int unused: 2; > unsigned int foo: 20; > unsigned int bar: 10; > } foo = { > .foo = 5, > }; > > int main(int argc, char *argv[]) > { > long local = 0x1234; > > return 127; > } > > # gcc -o foo -g foo.c > > # objdump -d foo | grep -A9 -F '<main>' > 00000000004004b0 <main>: > 4004b0: 55 push %rbp > 4004b1: 48 89 e5 mov %rsp,%rbp > 4004b4: 89 7d ec mov %edi,-0x14(%rbp) > 4004b7: 48 89 75 e0 mov %rsi,-0x20(%rbp) > 4004bb: 48 c7 45 f8 34 12 00 movq $0x1234,-0x8(%rbp) > 4004c2: 00 > 4004c3: b8 7f 00 00 00 mov $0x7f,%eax > 4004c8: 5d pop %rbp > 4004c9: c3 retq > > # nm foo | grep -e glob$ -e str -e foo > 00000000006008bc D foo > 00000000006008a8 D glob > 00000000006008ac D str > > # perf probe -x /home/namhyung/tmp/foo -a 'foo=main+0x13 glob=@0x8a8:s32 \ > > str=@0x8ac:string bit=@0x8bc:b10@2/32 argc=%di local=-0x8(%bp)' > Added new event: > probe_foo:foo (on 0x4c3 with glob=@0x8a8:s32 str=@0x8ac:string > bit=@0x8bc:b10@2/32 argc=%di local=-0x8(%bp)) > > You can now use it in all perf tools, such as: > > perf record -e probe_foo:foo -aR sleep 1 > > # perf record -e probe_foo:foo ./foo > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.001 MB perf.data (~33 samples) ] > > # perf script | grep -v ^# > foo 2008 [002 2199.867154: probe_foo:foo (4004c3) > glob=-1 str="hello uprobe." bit=5 argc=1 local=1234 Nice ! :) Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
