ftrace has way too much knowledge of our kernel module trampoline layout hidden inside it. Create module_trampoline_target() that gives the target address of a kernel module trampoline.
Signed-off-by: Anton Blanchard <[email protected]> --- arch/powerpc/include/asm/module.h | 2 ++ arch/powerpc/kernel/module_64.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h index f2711f0..dcfcad1 100644 --- a/arch/powerpc/include/asm/module.h +++ b/arch/powerpc/include/asm/module.h @@ -79,6 +79,8 @@ struct mod_arch_specific { #endif bool is_module_trampoline(u32 *insns); +int module_trampoline_target(struct module *mod, u32 *trampoline, + unsigned long *target); struct exception_table_entry; void sort_ex_table(struct exception_table_entry *start, diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index 4db5ecd..ef349d0 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -176,6 +176,35 @@ bool is_module_trampoline(u32 *p) return true; } +int module_trampoline_target(struct module *mod, u32 *trampoline, + unsigned long *target) +{ + u32 buf[2]; + u16 upper, lower; + long offset; + void *toc_entry; + + if (probe_kernel_read(buf, trampoline, sizeof(buf))) + return -EFAULT; + + upper = buf[0] & 0xffff; + lower = buf[1] & 0xffff; + + /* perform the addis/addi, both signed */ + offset = ((short)upper << 16) + (short)lower; + + /* + * Now get the address this trampoline jumps to. This + * is always 32 bytes into our trampoline stub. + */ + toc_entry = (void *)mod->arch.toc + offset + 32; + + if (probe_kernel_read(target, toc_entry, sizeof(*target))) + return -EFAULT; + + return 0; +} + #endif /* Count how many different 24-bit relocations (different symbol, -- 1.8.3.2 _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
