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Message-Id: <96f53c237316dab4b1b8c682685266faa92da816.1651905939.git.christophe.leroy@csgroup.eu>
Date: Sat, 7 May 2022 08:46:13 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
naveen.n.rao@...ux.vnet.ibm.com
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 11/25] powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64
Since c93d4f6ecf4b ("powerpc/ftrace: Add module_trampoline_target()
for PPC32"), __ftrace_make_nop() for PPC32 is very similar to the
one for PPC64.
Same for __ftrace_make_call().
Make them common.
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
v2:
- Fixed comment to -mprofile-kernel versus -mkernel_profile
- Replaced a couple of #ifdef with CONFIG_PPC64_ELF_ABI_V1 as suggested by Naveen.
---
arch/powerpc/kernel/trace/ftrace.c | 108 +++--------------------------
1 file changed, 8 insertions(+), 100 deletions(-)
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 0b199fc9cfd3..531da4d93c58 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -114,7 +114,6 @@ static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op)
}
#ifdef CONFIG_MODULES
-#ifdef CONFIG_PPC64
static int
__ftrace_make_nop(struct module *mod,
struct dyn_ftrace *rec, unsigned long addr)
@@ -154,10 +153,11 @@ __ftrace_make_nop(struct module *mod,
return -EINVAL;
}
-#ifdef CONFIG_MPROFILE_KERNEL
- /* When using -mkernel_profile there is no load to jump over */
+ /* When using -mprofile-kernel or PPC32 there is no load to jump over */
pop = ppc_inst(PPC_RAW_NOP());
+#ifdef CONFIG_PPC64
+#ifdef CONFIG_MPROFILE_KERNEL
if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) {
pr_err("Fetching instruction at %lx failed.\n", ip - 4);
return -EFAULT;
@@ -201,6 +201,7 @@ __ftrace_make_nop(struct module *mod,
return -EINVAL;
}
#endif /* CONFIG_MPROFILE_KERNEL */
+#endif /* PPC64 */
if (patch_instruction((u32 *)ip, pop)) {
pr_err("Patching NOP failed.\n");
@@ -209,48 +210,6 @@ __ftrace_make_nop(struct module *mod,
return 0;
}
-
-#else /* !PPC64 */
-static int
-__ftrace_make_nop(struct module *mod,
- struct dyn_ftrace *rec, unsigned long addr)
-{
- ppc_inst_t op;
- unsigned long ip = rec->ip;
- unsigned long tramp, ptr;
-
- if (copy_from_kernel_nofault(&op, (void *)ip, MCOUNT_INSN_SIZE))
- return -EFAULT;
-
- /* Make sure that that this is still a 24bit jump */
- if (!is_bl_op(op)) {
- pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));
- return -EINVAL;
- }
-
- /* lets find where the pointer goes */
- tramp = find_bl_target(ip, op);
-
- /* Find where the trampoline jumps to */
- if (module_trampoline_target(mod, tramp, &ptr)) {
- pr_err("Failed to get trampoline target\n");
- return -EFAULT;
- }
-
- if (ptr != addr) {
- pr_err("Trampoline location %08lx does not match addr\n",
- tramp);
- return -EINVAL;
- }
-
- op = ppc_inst(PPC_RAW_NOP());
-
- if (patch_instruction((u32 *)ip, op))
- return -EPERM;
-
- return 0;
-}
-#endif /* PPC64 */
#endif /* CONFIG_MODULES */
static unsigned long find_ftrace_tramp(unsigned long ip)
@@ -437,13 +396,12 @@ int ftrace_make_nop(struct module *mod,
}
#ifdef CONFIG_MODULES
-#ifdef CONFIG_PPC64
/*
* Examine the existing instructions for __ftrace_make_call.
* They should effectively be a NOP, and follow formal constraints,
* depending on the ABI. Return false if they don't.
*/
-#ifndef CONFIG_MPROFILE_KERNEL
+#ifdef CONFIG_PPC64_ELF_ABI_V1
static int
expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
{
@@ -465,7 +423,7 @@ expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
static int
expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
{
- /* look for patched "NOP" on ppc64 with -mprofile-kernel */
+ /* look for patched "NOP" on ppc64 with -mprofile-kernel or ppc32 */
if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())))
return 0;
return 1;
@@ -484,8 +442,10 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
if (copy_inst_from_kernel_nofault(op, ip))
return -EFAULT;
+#ifdef CONFIG_PPC64_ELF_ABI_V1
if (copy_inst_from_kernel_nofault(op + 1, ip + 4))
return -EFAULT;
+#endif
if (!expected_nop_sequence(ip, op[0], op[1])) {
pr_err("Unexpected call sequence at %p: %s %s\n",
@@ -531,58 +491,6 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
return 0;
}
-
-#else /* !CONFIG_PPC64: */
-static int
-__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
-{
- int err;
- ppc_inst_t op;
- u32 *ip = (u32 *)rec->ip;
- struct module *mod = rec->arch.mod;
- unsigned long tramp;
-
- /* read where this goes */
- if (copy_inst_from_kernel_nofault(&op, ip))
- return -EFAULT;
-
- /* It should be pointing to a nop */
- if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) {
- pr_err("Expected NOP but have %s\n", ppc_inst_as_str(op));
- return -EINVAL;
- }
-
- /* If we never set up a trampoline to ftrace_caller, then bail */
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- if (!mod->arch.tramp || !mod->arch.tramp_regs) {
-#else
- if (!mod->arch.tramp) {
-#endif
- pr_err("No ftrace trampoline\n");
- return -EINVAL;
- }
-
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- if (rec->flags & FTRACE_FL_REGS)
- tramp = mod->arch.tramp_regs;
- else
-#endif
- tramp = mod->arch.tramp;
- /* create the branch to the trampoline */
- err = create_branch(&op, ip, tramp, BRANCH_SET_LINK);
- if (err) {
- pr_err("REL24 out of range!\n");
- return -EINVAL;
- }
-
- pr_devel("write to %lx\n", rec->ip);
-
- if (patch_instruction(ip, op))
- return -EPERM;
-
- return 0;
-}
-#endif /* CONFIG_PPC64 */
#endif /* CONFIG_MODULES */
static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)
--
2.35.1
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