From: Heiko Carstens <hca@xxxxxxxxxxxxx>
[ Upstream commit b860b9346e2d5667fbae2cefc571bdb6ce665b53 ]
ftrace_shared_hotpatch_trampoline() never returns NULL,
therefore quite a bit of code can be removed.
Acked-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Stable-dep-of: 2a8db5ec4a28 ("RISC-V: Don't check text_mutex during stop_machine")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/s390/kernel/ftrace.c | 86 +++------------------------------------
1 file changed, 6 insertions(+), 80 deletions(-)
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 1d94ffdf347bb..5d0c45c13b5fa 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -80,17 +80,6 @@ asm(
#ifdef CONFIG_MODULES
static char *ftrace_plt;
-
-asm(
- " .data\n"
- "ftrace_plt_template:\n"
- " basr %r1,%r0\n"
- " lg %r1,0f-.(%r1)\n"
- " br %r1\n"
- "0: .quad ftrace_caller\n"
- "ftrace_plt_template_end:\n"
- " .previous\n"
-);
#endif /* CONFIG_MODULES */
static const char *ftrace_shared_hotpatch_trampoline(const char **end)
@@ -116,7 +105,7 @@ static const char *ftrace_shared_hotpatch_trampoline(const char **end)
bool ftrace_need_init_nop(void)
{
- return ftrace_shared_hotpatch_trampoline(NULL);
+ return true;
}
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
@@ -175,28 +164,6 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
return 0;
}
-static void ftrace_generate_nop_insn(struct ftrace_insn *insn)
-{
- /* brcl 0,0 */
- insn->opc = 0xc004;
- insn->disp = 0;
-}
-
-static void ftrace_generate_call_insn(struct ftrace_insn *insn,
- unsigned long ip)
-{
- unsigned long target;
-
- /* brasl r0,ftrace_caller */
- target = FTRACE_ADDR;
-#ifdef CONFIG_MODULES
- if (is_module_addr((void *)ip))
- target = (unsigned long)ftrace_plt;
-#endif /* CONFIG_MODULES */
- insn->opc = 0xc005;
- insn->disp = (target - ip) / 2;
-}
-
static void brcl_disable(void *brcl)
{
u8 op = 0x04; /* set mask field to zero */
@@ -207,23 +174,7 @@ static void brcl_disable(void *brcl)
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
- struct ftrace_insn orig, new, old;
-
- if (ftrace_shared_hotpatch_trampoline(NULL)) {
- brcl_disable((void *)rec->ip);
- return 0;
- }
-
- if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old)))
- return -EFAULT;
- /* Replace ftrace call with a nop. */
- ftrace_generate_call_insn(&orig, rec->ip);
- ftrace_generate_nop_insn(&new);
-
- /* Verify that the to be replaced code matches what we expect. */
- if (memcmp(&orig, &old, sizeof(old)))
- return -EINVAL;
- s390_kernel_write((void *) rec->ip, &new, sizeof(new));
+ brcl_disable((void *)rec->ip);
return 0;
}
@@ -236,23 +187,7 @@ static void brcl_enable(void *brcl)
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
- struct ftrace_insn orig, new, old;
-
- if (ftrace_shared_hotpatch_trampoline(NULL)) {
- brcl_enable((void *)rec->ip);
- return 0;
- }
-
- if (copy_from_kernel_nofault(&old, (void *) rec->ip, sizeof(old)))
- return -EFAULT;
- /* Replace nop with an ftrace call. */
- ftrace_generate_nop_insn(&orig);
- ftrace_generate_call_insn(&new, rec->ip);
-
- /* Verify that the to be replaced code matches what we expect. */
- if (memcmp(&orig, &old, sizeof(old)))
- return -EINVAL;
- s390_kernel_write((void *) rec->ip, &new, sizeof(new));
+ brcl_enable((void *)rec->ip);
return 0;
}
@@ -269,10 +204,7 @@ int __init ftrace_dyn_arch_init(void)
void arch_ftrace_update_code(int command)
{
- if (ftrace_shared_hotpatch_trampoline(NULL))
- ftrace_modify_all_code(command);
- else
- ftrace_run_stop_machine(command);
+ ftrace_modify_all_code(command);
}
static void __ftrace_sync(void *dummy)
@@ -281,10 +213,8 @@ static void __ftrace_sync(void *dummy)
int ftrace_arch_code_modify_post_process(void)
{
- if (ftrace_shared_hotpatch_trampoline(NULL)) {
- /* Send SIGP to the other CPUs, so they see the new code. */
- smp_call_function(__ftrace_sync, NULL, 1);
- }
+ /* Send SIGP to the other CPUs, so they see the new code. */
+ smp_call_function(__ftrace_sync, NULL, 1);
return 0;
}
@@ -299,10 +229,6 @@ static int __init ftrace_plt_init(void)
panic("cannot allocate ftrace plt\n");
start = ftrace_shared_hotpatch_trampoline(&end);
- if (!start) {
- start = ftrace_plt_template;
- end = ftrace_plt_template_end;
- }
memcpy(ftrace_plt, start, end - start);
set_memory_ro((unsigned long)ftrace_plt, 1);
return 0;
--
2.39.2
