Commit ae3a2a21 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/ftrace: Remove redundant create_branch() calls 



Since commit d5937db1 ("powerpc/code-patching: Fix patch_branch()
return on out-of-range failure") patch_branch() fails with -ERANGE
when trying to branch out of range.

No need to perform the test twice. Remove redundant create_branch()
calls.

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/aa45fbad0b4b7493080835d8276c0cb4ce146503.1652074503.git.christophe.leroy@csgroup.eu
parent d996d505

arch/powerpc/kernel/trace/ftrace.c

+0 −20
Original line number Diff line number Diff line
@@ -301,7 +301,6 @@ static int setup_mcount_compiler_tramp(unsigned long tramp) 
	int i;

	ppc_inst_t op;

	unsigned long ptr;

	ppc_inst_t instr;

	static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS];



	/* Is this a known long jump tramp? */
@@ -344,12 +343,6 @@ static int setup_mcount_compiler_tramp(unsigned long tramp) 
#else

	ptr = ppc_global_function_entry((void *)ftrace_caller);

#endif

	if (create_branch(&instr, (void *)tramp, ptr, 0)) {

		pr_debug("%ps is not reachable from existing mcount tramp\n",

				(void *)ptr);

		return -1;

	}



	if (patch_branch((u32 *)tramp, ptr, 0)) {

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

		return -1;
@@ -490,7 +483,6 @@ static int 
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

{

	ppc_inst_t op[2];

	ppc_inst_t instr;

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

	unsigned long entry, ptr, tramp;

	struct module *mod = rec->arch.mod;
@@ -539,12 +531,6 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) 
		return -EINVAL;

	}



	/* Ensure branch is within 24 bits */

	if (create_branch(&instr, ip, tramp, BRANCH_SET_LINK)) {

		pr_err("Branch out of range\n");

		return -EINVAL;

	}



	if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {

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

		return -EINVAL;
@@ -770,12 +756,6 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 
		return -EINVAL;

	}



	/* Ensure branch is within 24 bits */

	if (create_branch(&op, (u32 *)ip, tramp, BRANCH_SET_LINK)) {

		pr_err("Branch out of range\n");

		return -EINVAL;

	}



	if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) {

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

		return -EINVAL;