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Commit dd9fa162 authored by Anton Blanchard's avatar Anton Blanchard
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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

arch/powerpc/include/asm/module.h

+2 −0
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/kernel/module_64.c

+29 −0
Original line number Diff line number Diff line
@@ -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,