From c75388a8ceffbf1bf72c61afe66a72e58aa20c74 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 20 Dec 2021 16:38:25 +0000 Subject: [PATCH] powerpc/ftrace: Prepare PPC64's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS In order to implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS, change ftrace_caller() to handle LIVEPATCH the same way as frace_caller_regs(). Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/850817333cc76593699032e8e9a70d8c36e1af1e.1640017960.git.christophe.leroy@csgroup.eu --- arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S index d636fc7..f6f78781 100644 --- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S @@ -172,14 +172,19 @@ _GLOBAL(ftrace_caller) addi r3, r3, function_trace_op@toc@l ld r5, 0(r3) +#ifdef CONFIG_LIVEPATCH_64 + SAVE_GPR(14, r1) + mr r14,r7 /* remember old NIP */ +#endif /* Calculate ip from nip-4 into r3 for call below */ subi r3, r7, MCOUNT_INSN_SIZE /* Put the original return address in r4 as parent_ip */ + std r0, _LINK(r1) mr r4, r0 - /* Set pt_regs to NULL */ - li r6, 0 + /* Load &pt_regs in r6 for call below */ + addi r6, r1 ,STACK_FRAME_OVERHEAD /* ftrace_call(r3, r4, r5, r6) */ .globl ftrace_call @@ -189,6 +194,10 @@ ftrace_call: ld r3, _NIP(r1) mtctr r3 +#ifdef CONFIG_LIVEPATCH_64 + cmpd r14, r3 /* has NIP been altered? */ + REST_GPR(14, r1) +#endif /* Restore gprs */ REST_GPRS(3, 10, r1) @@ -196,13 +205,17 @@ ftrace_call: /* Restore callee's TOC */ ld r2, 24(r1) + /* Restore possibly modified LR */ + ld r0, _LINK(r1) + mtlr r0 + /* Pop our stack frame */ addi r1, r1, SWITCH_FRAME_SIZE - /* Reload original LR */ - ld r0, LRSAVE(r1) - mtlr r0 - +#ifdef CONFIG_LIVEPATCH_64 + /* Based on the cmpd above, if the NIP was altered handle livepatch */ + bne- livepatch_handler +#endif /* Handle function_graph or go back */ b ftrace_caller_common -- 2.7.4