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author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-04-19 14:52:27 +0200 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-24 11:07:58 +0200 |
commit | 1b32cd1715378c9a3856df4a80920f8e241f914c (patch) | |
tree | 4f8a016601e31101e6b26c44ab563cc680dc7ff1 /arch/powerpc/include/asm/code-patching.h | |
parent | powerpc/kprobes: Add support for KPROBES_ON_FTRACE (diff) | |
download | linux-1b32cd1715378c9a3856df4a80920f8e241f914c.tar.xz linux-1b32cd1715378c9a3856df4a80920f8e241f914c.zip |
powerpc: Introduce a new helper to obtain function entry points
kprobe_lookup_name() is specific to the kprobe subsystem and may not always
return the function entry point (in a subsequent patch for KPROBES_ON_FTRACE).
For looking up function entry points, introduce a separate helper and use it
in optprobes.c
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/code-patching.h')
-rw-r--r-- | arch/powerpc/include/asm/code-patching.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h index 8ab937771068..abef812de7f8 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -12,6 +12,8 @@ #include <asm/types.h> #include <asm/ppc-opcode.h> +#include <linux/string.h> +#include <linux/kallsyms.h> /* Flags for create_branch: * "b" == create_branch(addr, target, 0); @@ -99,6 +101,45 @@ static inline unsigned long ppc_global_function_entry(void *func) #endif } +/* + * Wrapper around kallsyms_lookup() to return function entry address: + * - For ABIv1, we lookup the dot variant. + * - For ABIv2, we return the local entry point. + */ +static inline unsigned long ppc_kallsyms_lookup_name(const char *name) +{ + unsigned long addr; +#ifdef PPC64_ELF_ABI_v1 + /* check for dot variant */ + char dot_name[1 + KSYM_NAME_LEN]; + bool dot_appended = false; + + if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN) + return 0; + + if (name[0] != '.') { + dot_name[0] = '.'; + dot_name[1] = '\0'; + strlcat(dot_name, name, sizeof(dot_name)); + dot_appended = true; + } else { + dot_name[0] = '\0'; + strlcat(dot_name, name, sizeof(dot_name)); + } + addr = kallsyms_lookup_name(dot_name); + if (!addr && dot_appended) + /* Let's try the original non-dot symbol lookup */ + addr = kallsyms_lookup_name(name); +#elif defined(PPC64_ELF_ABI_v2) + addr = kallsyms_lookup_name(name); + if (addr) + addr = ppc_function_entry((void *)addr); +#else + addr = kallsyms_lookup_name(name); +#endif + return addr; +} + #ifdef CONFIG_PPC64 /* * Some instruction encodings commonly used in dynamic ftracing |