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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@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/912ae51782f5a53c44e435497c8c3fb5cc632387.1652074503.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2022-05-09 07:36:02 +02:00 committed by Michael Ellerman
parent 1acbf27e8a
commit a1facd2578
1 changed files with 2 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/powerpc/kernel/trace/ftrace.c
View File

@ -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;