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powerpc/modules: Create module_trampoline_target()

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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 <anton@samba.org>
This commit is contained in:
Anton Blanchard 2014-04-04 15:58:42 +11:00
parent 83775b8566
commit dd9fa16250
2 changed files with 31 additions and 0 deletions
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2
arch/powerpc/include/asm/module.h
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@ -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,

29
arch/powerpc/kernel/module_64.c
View File

@ -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,