On Fri, Jun 13, 2014 at 11:45:21AM -0700, Simon Que wrote:
> The function machine__get_kernel_start_addr() was taking the first symbol
> of kallsyms as the start address. This is incorrect in certain cases
> where the first symbol is something at 0, while the actual kernel
> functions begin at a later point (e.g. 0x80200000).
>
> This patch fixes machine__get_kernel_start_addr() to search for the
> symbol "_text" or "_stext", which marks the beginning of kernel mapping.
> This was already being done in machine__create_kernel_maps(). Thus, this
> patch is just a refactor, to move that code into
> machine__get_kernel_start_addr().
>
> Change-Id: I0c38c36f5e8b0f4fb92a6f57211fa45aabe545a6
> Signed-off-by: Simon Que <s...@chromium.org>
hi,
looks good to me, adding Adrian to the loop
thanks,
jirka
> ---
> tools/perf/util/machine.c | 54
> +++++++++++++++++++----------------------------
> 1 file changed, 22 insertions(+), 32 deletions(-)
>
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index 620a198..acda3d2 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -484,18 +484,6 @@ struct process_args {
> u64 start;
> };
>
> -static int symbol__in_kernel(void *arg, const char *name,
> - char type __maybe_unused, u64 start)
> -{
> - struct process_args *args = arg;
> -
> - if (strchr(name, '['))
> - return 0;
> -
> - args->start = start;
> - return 1;
> -}
> -
> static void machine__get_kallsyms_filename(struct machine *machine, char
> *buf,
> size_t bufsz)
> {
> @@ -505,27 +493,41 @@ static void machine__get_kallsyms_filename(struct
> machine *machine, char *buf,
> scnprintf(buf, bufsz, "%s/proc/kallsyms", machine->root_dir);
> }
>
> -/* Figure out the start address of kernel map from /proc/kallsyms */
> -static u64 machine__get_kernel_start_addr(struct machine *machine)
> +const char *ref_reloc_sym_names[] = {"_text", "_stext", NULL};
> +
> +/* Figure out the start address of kernel map from /proc/kallsyms.
> + * Returns the name of the start symbol in *symbol_name. Pass in NULL as
> + * symbol_name if it's not that important.
> + */
> +static u64 machine__get_kernel_start_addr(struct machine *machine,
> + const char** symbol_name)
> {
> char filename[PATH_MAX];
> - struct process_args args;
> + int i;
> + const char* name;
> + u64 addr;
>
> machine__get_kallsyms_filename(machine, filename, PATH_MAX);
>
> if (symbol__restricted_filename(filename, "/proc/kallsyms"))
> return 0;
>
> - if (kallsyms__parse(filename, &args, symbol__in_kernel) <= 0)
> - return 0;
> + for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
> + addr = kallsyms__get_function_start(filename, name);
> + if (addr)
> + break;
> + }
> +
> + if (symbol_name)
> + *symbol_name = name;
>
> - return args.start;
> + return addr;
> }
>
> int __machine__create_kernel_maps(struct machine *machine, struct dso
> *kernel)
> {
> enum map_type type;
> - u64 start = machine__get_kernel_start_addr(machine);
> + u64 start = machine__get_kernel_start_addr(machine, NULL);
>
> for (type = 0; type < MAP__NR_TYPES; ++type) {
> struct kmap *kmap;
> @@ -832,23 +834,11 @@ static int machine__create_modules(struct machine
> *machine)
> return 0;
> }
>
> -const char *ref_reloc_sym_names[] = {"_text", "_stext", NULL};
> -
> int machine__create_kernel_maps(struct machine *machine)
> {
> struct dso *kernel = machine__get_kernel(machine);
> - char filename[PATH_MAX];
> const char *name;
> - u64 addr = 0;
> - int i;
> -
> - machine__get_kallsyms_filename(machine, filename, PATH_MAX);
> -
> - for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
> - addr = kallsyms__get_function_start(filename, name);
> - if (addr)
> - break;
> - }
> + u64 addr = machine__get_kernel_start_addr(machine, &name);
> if (!addr)
> return -1;
>
> --
> 1.8.3.2
>
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