On Thu, Oct 17, 2019 at 11:08 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote:
>
> In preparation for module support for kunit and kunit tests,
> we need a way of retrieving non-exported symbols from the
> core kernel and modules. kunit_find_symbol() supports this.
>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> Signed-off-by: Knut Omang <knut.omang@xxxxxxxxxx>
I think you suggested on another thread that splitting this patch out
of this patchset might be a good idea. I agree with that. Can you send
this patch separately?
> ---
> include/kunit/test.h | 8 ++++++++
> lib/kunit/test-test.c | 19 +++++++++++++++++++
> lib/kunit/test.c | 36 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 63 insertions(+)
>
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index dba4830..c645d18 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -339,6 +339,14 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
>
> void kunit_cleanup(struct kunit *test);
>
> +/**
> + * kunit_find_symbol() - lookup un-exported symbol in kernel or modules.
> + * @sym: symbol name.
> + *
> + * Returns symbol or ERR_PTR value on error.
Can you document which ERR_PTRs it returns?
> + */
> +void *kunit_find_symbol(const char *sym);
> +
> #define kunit_printk(lvl, test, fmt, ...) \
> printk(lvl "\t# %s: " fmt, (test)->name, ##__VA_ARGS__)
>
> diff --git a/lib/kunit/test-test.c b/lib/kunit/test-test.c
> index c4162a9..7f09dd0 100644
> --- a/lib/kunit/test-test.c
> +++ b/lib/kunit/test-test.c
> @@ -330,3 +330,22 @@ static void kunit_resource_test_exit(struct kunit *test)
> .test_cases = kunit_resource_test_cases,
> };
> kunit_test_suite(kunit_resource_test_suite);
> +
> +/*
> + * Find non-exported kernel symbol; we use the modules list as a safe
> + * choice that should always be present.
> + */
> +static void kunit_find_symbol_kernel(struct kunit *test)
> +{
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, kunit_find_symbol("modules"));
I think this should be a KUNIT_EXPECT_... here since nothing in this
test case depends on this check passing.
> +}
> +
> +static struct kunit_case kunit_find_symbol_test_cases[] = {
> + KUNIT_CASE(kunit_find_symbol_kernel),
> +};
> +
> +static struct kunit_suite kunit_find_symbol_test_suite = {
> + .name = "kunit-find-symbol",
> + .test_cases = kunit_find_symbol_test_cases,
> +};
> +kunit_test_suite(kunit_find_symbol_test_suite);
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index 49ac5fe..a2b1b46 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -8,6 +8,7 @@
>
> #include <kunit/test.h>
> #include <kunit/try-catch.h>
> +#include <linux/kallsyms.h>
> #include <linux/kernel.h>
> #include <linux/sched/debug.h>
> #include "string-stream-impl.h"
> @@ -478,3 +479,38 @@ void kunit_cleanup(struct kunit *test)
> kunit_resource_free(test, resource);
> }
> }
> +
> +/*
> + * Support for looking up kernel/module internal symbols to enable testing.
> + */
> +void *kunit_find_symbol(const char *sym)
> +{
> + unsigned long (*modlookup)(const char *name);
> + unsigned long addr = 0;
> +
> + if (!sym || strlen(sym) > KSYM_NAME_LEN)
> + return ERR_PTR(-EINVAL);
> +
> + /*
> + * Try for kernel-internal symbol first; fall back to modules
> + * if that fails.
> + */
> + addr = kallsyms_lookup_name(sym);
> + if (addr)
> + return (void *)addr;
nit: please add a newline here.
> + modlookup = (void *)kallsyms_lookup_name("module_kallsyms_lookup_name");
Can you add a comment here explaining what module_kallsyms_lookup_name
is and why you need to look it up this way?
> + if (modlookup)
> + addr = modlookup(sym);
> + if (addr)
> + return (void *)addr;
> +
> +#ifndef CONFIG_KALLSYMS_ALL
> + WARN_ONCE(true,
> + "CONFIG_KALLSYMS_ALL is not set, so unexported symbols like '%s' are not available\n",
> + sym);
> + return ERR_PTR(-ENOTSUPP);
> +#else
> + WARN_ONCE(true, "symbol '%s' is not available\n", sym);
> +#endif
> + return ERR_PTR(-ENOENT);
> +}
> --
> 1.8.3.1
>
