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Date: Thu, 24 Mar 2022 15:29:54 +0100 From: Christophe Leroy <christophe.leroy@...roup.eu> To: "Naveen N . Rao" <naveen.n.rao@...ux.vnet.ibm.com>, Steven Rostedt <rostedt@...dmis.org>, Ingo Molnar <mingo@...hat.com>, Benjamin Herrenschmidt <benh@...nel.crashing.org>, Paul Mackerras <paulus@...ba.org>, Michael Ellerman <mpe@...erman.id.au> Cc: Christophe Leroy <christophe.leroy@...roup.eu>, linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org Subject: [PATCH v1 04/22] 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: Christophe Leroy <christophe.leroy@...roup.eu> --- arch/powerpc/kernel/trace/ftrace.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 3ce3697e8a7c..41c45b9c7f39 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -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; -- 2.35.1
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