Commit a1facd25 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/ftrace: Use is_offset_in_branch_range() 



Use is_offset_in_branch_range() instead of create_branch()
to check if a target is within branch range.

This patch together with the previous one improves
ftrace activation time by 7%

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/912ae51782f5a53c44e435497c8c3fb5cc632387.1652074503.git.christophe.leroy@csgroup.eu
parent 1acbf27e

arch/powerpc/kernel/trace/ftrace.c

+2 −6
Original line number Diff line number Diff line
@@ -89,11 +89,9 @@ ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) 
 */

static int test_24bit_addr(unsigned long ip, unsigned long addr)

{

	ppc_inst_t op;

	addr = ppc_function_entry((void *)addr);



	/* use the create_branch to verify that this offset can be branched */

	return create_branch(&op, (u32 *)ip, addr, 0) == 0;

	return is_offset_in_branch_range(addr - ip);

}



static int is_bl_op(ppc_inst_t op)
@@ -261,7 +259,6 @@ __ftrace_make_nop(struct module *mod, 
static unsigned long find_ftrace_tramp(unsigned long ip)

{

	int i;

	ppc_inst_t instr;



	/*

	 * We have the compiler generated long_branch tramps at the end
@@ -270,8 +267,7 @@ static unsigned long find_ftrace_tramp(unsigned long ip) 
	for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--)

		if (!ftrace_tramps[i])

			continue;

		else if (create_branch(&instr, (void *)ip,

				       ftrace_tramps[i], 0) == 0)

		else if (is_offset_in_branch_range(ftrace_tramps[i] - ip))

			return ftrace_tramps[i];



	return 0;