Commit 23b44fc2 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64 



Since c93d4f6e ("powerpc/ftrace: Add module_trampoline_target()
for PPC32"), __ftrace_make_nop() for PPC32 is very similar to the
one for PPC64.

Same for __ftrace_make_call().

Make them common.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/96f53c237316dab4b1b8c682685266faa92da816.1652074503.git.christophe.leroy@csgroup.eu
parent 5b89492c

arch/powerpc/kernel/trace/ftrace.c

+8 −100
Original line number Diff line number Diff line
@@ -114,7 +114,6 @@ static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) 
}



#ifdef CONFIG_MODULES

#ifdef CONFIG_PPC64

static int

__ftrace_make_nop(struct module *mod,

		  struct dyn_ftrace *rec, unsigned long addr)
@@ -154,10 +153,11 @@ __ftrace_make_nop(struct module *mod, 
		return -EINVAL;

	}



#ifdef CONFIG_MPROFILE_KERNEL

	/* When using -mkernel_profile there is no load to jump over */

	/* When using -mprofile-kernel or PPC32 there is no load to jump over */

	pop = ppc_inst(PPC_RAW_NOP());



#ifdef CONFIG_PPC64

#ifdef CONFIG_MPROFILE_KERNEL

	if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) {

		pr_err("Fetching instruction at %lx failed.\n", ip - 4);

		return -EFAULT;
@@ -201,6 +201,7 @@ __ftrace_make_nop(struct module *mod, 
		return -EINVAL;

	}

#endif /* CONFIG_MPROFILE_KERNEL */

#endif /* PPC64 */



	if (patch_instruction((u32 *)ip, pop)) {

		pr_err("Patching NOP failed.\n");
@@ -209,48 +210,6 @@ __ftrace_make_nop(struct module *mod, 


	return 0;

}



#else /* !PPC64 */

static int

__ftrace_make_nop(struct module *mod,

		  struct dyn_ftrace *rec, unsigned long addr)

{

	ppc_inst_t op;

	unsigned long ip = rec->ip;

	unsigned long tramp, ptr;



	if (copy_from_kernel_nofault(&op, (void *)ip, MCOUNT_INSN_SIZE))

		return -EFAULT;



	/* Make sure that that this is still a 24bit jump */

	if (!is_bl_op(op)) {

		pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));

		return -EINVAL;

	}



	/* lets find where the pointer goes */

	tramp = find_bl_target(ip, op);



	/* Find where the trampoline jumps to */

	if (module_trampoline_target(mod, tramp, &ptr)) {

		pr_err("Failed to get trampoline target\n");

		return -EFAULT;

	}



	if (ptr != addr) {

		pr_err("Trampoline location %08lx does not match addr\n",

		       tramp);

		return -EINVAL;

	}



	op = ppc_inst(PPC_RAW_NOP());



	if (patch_instruction((u32 *)ip, op))

		return -EPERM;



	return 0;

}

#endif /* PPC64 */

#endif /* CONFIG_MODULES */



static unsigned long find_ftrace_tramp(unsigned long ip)
@@ -437,13 +396,12 @@ int ftrace_make_nop(struct module *mod, 
}



#ifdef CONFIG_MODULES

#ifdef CONFIG_PPC64

/*

 * Examine the existing instructions for __ftrace_make_call.

 * They should effectively be a NOP, and follow formal constraints,

 * depending on the ABI. Return false if they don't.

 */

#ifndef CONFIG_MPROFILE_KERNEL

#ifdef CONFIG_PPC64_ELF_ABI_V1

static int

expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)

{
@@ -465,7 +423,7 @@ expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) 
static int

expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)

{

	/* look for patched "NOP" on ppc64 with -mprofile-kernel */

	/* look for patched "NOP" on ppc64 with -mprofile-kernel or ppc32 */

	if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())))

		return 0;

	return 1;
@@ -484,8 +442,10 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) 
	if (copy_inst_from_kernel_nofault(op, ip))

		return -EFAULT;



#ifdef CONFIG_PPC64_ELF_ABI_V1

	if (copy_inst_from_kernel_nofault(op + 1, ip + 4))

		return -EFAULT;

#endif



	if (!expected_nop_sequence(ip, op[0], op[1])) {

		pr_err("Unexpected call sequence at %p: %s %s\n",
@@ -531,58 +491,6 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) 


	return 0;

}



#else  /* !CONFIG_PPC64: */

static int

__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

{

	int err;

	ppc_inst_t op;

	u32 *ip = (u32 *)rec->ip;

	struct module *mod = rec->arch.mod;

	unsigned long tramp;



	/* read where this goes */

	if (copy_inst_from_kernel_nofault(&op, ip))

		return -EFAULT;



	/* It should be pointing to a nop */

	if (!ppc_inst_equal(op,  ppc_inst(PPC_RAW_NOP()))) {

		pr_err("Expected NOP but have %s\n", ppc_inst_as_str(op));

		return -EINVAL;

	}



	/* If we never set up a trampoline to ftrace_caller, then bail */

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS

	if (!mod->arch.tramp || !mod->arch.tramp_regs) {

#else

	if (!mod->arch.tramp) {

#endif

		pr_err("No ftrace trampoline\n");

		return -EINVAL;

	}



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS

	if (rec->flags & FTRACE_FL_REGS)

		tramp = mod->arch.tramp_regs;

	else

#endif

		tramp = mod->arch.tramp;

	/* create the branch to the trampoline */

	err = create_branch(&op, ip, tramp, BRANCH_SET_LINK);

	if (err) {

		pr_err("REL24 out of range!\n");

		return -EINVAL;

	}



	pr_devel("write to %lx\n", rec->ip);



	if (patch_instruction(ip, op))

		return -EPERM;



	return 0;

}

#endif /* CONFIG_PPC64 */

#endif /* CONFIG_MODULES */



static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)