This is a note to let you know that I've just added the patch titled powerpc/ftrace: Remove ftrace init tramp once kernel init is complete to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-ftrace-remove-ftrace-init-tramp-once-kernel-init-is-complete.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 84ade0a6655bee803d176525ef457175cbf4df22 Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Date: Mon, 16 May 2022 12:44:22 +0530 Subject: powerpc/ftrace: Remove ftrace init tramp once kernel init is complete From: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> commit 84ade0a6655bee803d176525ef457175cbf4df22 upstream. Stop using the ftrace trampoline for init section once kernel init is complete. Fixes: 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs") Cc: stable@xxxxxxxxxxxxxxx # v4.20+ Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220516071422.463738-1-naveen.n.rao@xxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/include/asm/ftrace.h | 4 +++- arch/powerpc/kernel/trace/ftrace.c | 15 ++++++++++++--- arch/powerpc/mm/mem.c | 2 ++ 3 files changed, 17 insertions(+), 4 deletions(-) --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -96,7 +96,7 @@ static inline bool arch_syscall_match_sy #endif /* PPC64_ELF_ABI_v1 */ #endif /* CONFIG_FTRACE_SYSCALLS */ -#ifdef CONFIG_PPC64 +#if defined(CONFIG_PPC64) && defined(CONFIG_FUNCTION_TRACER) #include <asm/paca.h> static inline void this_cpu_disable_ftrace(void) @@ -120,11 +120,13 @@ static inline u8 this_cpu_get_ftrace_ena return get_paca()->ftrace_enabled; } +void ftrace_free_init_tramp(void); #else /* CONFIG_PPC64 */ static inline void this_cpu_disable_ftrace(void) { } static inline void this_cpu_enable_ftrace(void) { } static inline void this_cpu_set_ftrace_enabled(u8 ftrace_enabled) { } static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; } +static inline void ftrace_free_init_tramp(void) { } #endif /* CONFIG_PPC64 */ #endif /* !__ASSEMBLY__ */ --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -336,9 +336,7 @@ static int setup_mcount_compiler_tramp(u /* Is this a known long jump tramp? */ for (i = 0; i < NUM_FTRACE_TRAMPS; i++) - if (!ftrace_tramps[i]) - break; - else if (ftrace_tramps[i] == tramp) + if (ftrace_tramps[i] == tramp) return 0; /* Is this a known plt tramp? */ @@ -881,6 +879,17 @@ void arch_ftrace_update_code(int command extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; +void ftrace_free_init_tramp(void) +{ + int i; + + for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++) + if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) { + ftrace_tramps[i] = 0; + return; + } +} + int __init ftrace_dyn_arch_init(void) { int i; --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -22,6 +22,7 @@ #include <asm/kasan.h> #include <asm/svm.h> #include <asm/mmzone.h> +#include <asm/ftrace.h> #include <mm/mmu_decl.h> @@ -314,6 +315,7 @@ void free_initmem(void) mark_initmem_nx(); init_mem_is_free = true; free_initmem_default(POISON_FREE_INITMEM); + ftrace_free_init_tramp(); } /* Patches currently in stable-queue which might be from naveen.n.rao@xxxxxxxxxxxxxxxxxx are queue-5.15/powerpc-ftrace-remove-ftrace-init-tramp-once-kernel-init-is-complete.patch