[PATCH 5.19 1137/1157] powerpc64/ftrace: Fix ftrace for clang builds

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 21:08:24 EST


From: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>

commit cb928ac192128c842f4c1cfc8b6780b95719d65f upstream.

Clang doesn't support -mprofile-kernel ABI, so guard the checks against
CONFIG_DYNAMIC_FTRACE_WITH_REGS, rather than the elf ABI version.

Fixes: 23b44fc248f4 ("powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64")
Cc: stable@xxxxxxxxxxxxxxx # v5.19+
Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reported-by: Ondrej Mosnacek <omosnacek@xxxxxxxxx>
Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Tested-by: Ondrej Mosnacek <omosnacek@xxxxxxxxx>
Acked-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://github.com/llvm/llvm-project/issues/57031
Link: https://github.com/ClangBuiltLinux/linux/issues/1682
Link: https://lore.kernel.org/r/20220809095907.418764-1-naveen.n.rao@xxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/trace/ftrace.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -392,11 +392,11 @@ int ftrace_make_nop(struct module *mod,
*/
static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
{
- if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1))
+ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
+ return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP()));
+ else
return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) &&
ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC));
- else
- return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP()));
}

static int
@@ -411,7 +411,7 @@ __ftrace_make_call(struct dyn_ftrace *re
if (copy_inst_from_kernel_nofault(op, ip))
return -EFAULT;

- if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) &&
+ if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) &&
copy_inst_from_kernel_nofault(op + 1, ip + 4))
return -EFAULT;