Commit dd9fa162 authored by Anton Blanchard's avatar Anton Blanchard

powerpc/modules: Create module_trampoline_target()

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: default avatarAnton Blanchard <anton@samba.org>
parent 83775b85
...@@ -79,6 +79,8 @@ struct mod_arch_specific { ...@@ -79,6 +79,8 @@ struct mod_arch_specific {
#endif #endif
bool is_module_trampoline(u32 *insns); bool is_module_trampoline(u32 *insns);
int module_trampoline_target(struct module *mod, u32 *trampoline,
unsigned long *target);
struct exception_table_entry; struct exception_table_entry;
void sort_ex_table(struct exception_table_entry *start, void sort_ex_table(struct exception_table_entry *start,
......
...@@ -176,6 +176,35 @@ bool is_module_trampoline(u32 *p) ...@@ -176,6 +176,35 @@ bool is_module_trampoline(u32 *p)
return true; 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 #endif
/* Count how many different 24-bit relocations (different symbol, /* Count how many different 24-bit relocations (different symbol,
......
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