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SubjectRe: [PATCH v1 08/22] powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64
Christophe Leroy wrote:
> 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@csgroup.eu>
> ---
> 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 1b05d33f96c6..2c7e42e439bb 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 -mkernel_profile or PPC32 there is no load to jump over */
-mprofile-kernel

Since you are modifying that line anyway ^^


> 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
> +#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS

It is better to gate this on 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;
>
> +#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> if (copy_inst_from_kernel_nofault(op + 1, ip + 4))
> return -EFAULT;
> +#endif

Here too...


- Naveen

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