Le 09/02/2026 à 14:25, Xie Yuanbin a écrit :
On Fri, 6 Feb 2026 20:53:55 +0100, Christophe Leroy (CS GROUP) wrote:
Le 06/02/2026 à 19:26, Kees Cook a écrit :

Isn't it possible to do this and not need __compiletime_strlen at all?

        n_len = strnlen(name, min(__member_size(name), KSYM_NAME_LEN));

ppc_kallsyms_lookup_name() only has two callers and they call it with a
built-in string. I think we can do something a lot simpler, something
like (untested):

static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)
{
        unsigned long addr = kallsyms_lookup_name(name);

        if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)
                addr = ppc_function_entry((void *)addr);

        return addr;
}

#ifdef CONFIG_PPC64_ELF_ABI_V1
#define ppc_kallsyms_lookup_name(x)     __ppc_kallsyms_lookup_name("." ## x);
#else
#define ppc_kallsyms_lookup_name(x)     __ppc_kallsyms_lookup_name(x)
#endif

Christophe

When CONFIG_PPC64_ELF_ABI_V1=y, it seems that the try of lookupinp
the original non-dot symbol is missing.

What about this (Only the compilation test is performed):
```c
static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)
{
        unsigned long addr = kallsyms_lookup_name(name);

        if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)
                addr = ppc_function_entry((void *)addr);

        return addr;
}

#define ppc_kallsyms_lookup_name(x) ({                                  \
                unsigned long addr = 0;                                 \
                if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1))                \
                        addr = __ppc_kallsyms_lookup_name("." x);     \
                if (!addr)                                              \
                        addr = __ppc_kallsyms_lookup_name(x);           \
                addr;                                                   \
        })
```

Good point.

To avoid duplicating the string I'd suggest:

static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)
{
        unsigned long addr = kallsyms_lookup_name(name);

        if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) && !addr)
                addr = kallsyms_lookup_name(name + 1);
        if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)
                addr = ppc_function_entry((void *)addr);

        return addr;
}

#ifdef CONFIG_PPC64_ELF_ABI_V1
#define ppc_kallsyms_lookup_name(x)     __ppc_kallsyms_lookup_name("." x);
#else
#define ppc_kallsyms_lookup_name(x)     __ppc_kallsyms_lookup_name(x)
#endif

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