powerpc/ftrace: Add support for livepatch to PPC32

PPC64 needs some special logic to properly set up the TOC.
See commit 8580324cad5f ("powerpc/livepatch: Add live patching support
on ppc64le") for details.

PPC32 doesn't have TOC so it doesn't need that logic, so adding
LIVEPATCH support is straight forward.

Add CONFIG_LIVEPATCH_64 and move livepatch stack logic into that item.

Livepatch sample modules all work.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/63cb094125b6a6038c65eeac2abaabbabe63addd.1640017960.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b779603978e10017dcfed203654b0f3cf34ad2ba..1d027ce94ab12b08d4162b88a03243fafe7c6b61 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -9,6 +9,10 @@ config 64BIT
        bool
        default y if PPC64
 
+config LIVEPATCH_64
+       def_bool PPC64
+       depends on LIVEPATCH
+
 config MMU
        bool
        default y
@@ -221,7 +225,7 @@ config PPC
        select HAVE_KPROBES_ON_FTRACE
        select HAVE_KRETPROBES
        select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
-       select HAVE_LIVEPATCH                   if HAVE_DYNAMIC_FTRACE_WITH_REGS && PPC64
+       select HAVE_LIVEPATCH                   if HAVE_DYNAMIC_FTRACE_WITH_REGS
        select HAVE_MOD_ARCH_SPECIFIC
        select HAVE_NMI                         if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
        select HAVE_OPTPROBES

diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h
index 4fe018cc207bbfb3fa3145f28b7ecbef1d62e006..37af961eb74cc815d14551f41197fc3d3455fdba 100644 (file)
--- a/arch/powerpc/include/asm/livepatch.h
+++ b/arch/powerpc/include/asm/livepatch.h
@@ -23,12 +23,14 @@ static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
 static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
 {
        /*
-        * Live patch works only with -mprofile-kernel on PPC. In this case,
-        * the ftrace location is always within the first 16 bytes.
+        * Live patch works on PPC32 and only with -mprofile-kernel on PPC64. In
+        * both cases, the ftrace location is always within the first 16 bytes.
         */
        return ftrace_location_range(faddr, faddr + 16);
 }
+#endif /* CONFIG_LIVEPATCH */
 
+#ifdef CONFIG_LIVEPATCH_64
 static inline void klp_init_thread_info(struct task_struct *p)
 {
        /* + 1 to account for STACK_END_MAGIC */
@@ -36,6 +38,6 @@ static inline void klp_init_thread_info(struct task_struct *p)
 }
 #else
 static inline void klp_init_thread_info(struct task_struct *p) { }
-#endif /* CONFIG_LIVEPATCH */
+#endif
 
 #endif /* _ASM_POWERPC_LIVEPATCH_H */

diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index d6e649b3c70b679ed22cafc21130c5cc1ed42b58..125328d1b98027e12c36c0ebd3f3dab17892cbc2 100644 (file)
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -51,7 +51,7 @@ struct thread_info {
        unsigned int    cpu;
 #endif
        unsigned long   local_flags;            /* private flags for thread */
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
        unsigned long *livepatch_sp;
 #endif
 #if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC32)

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 7582f3e3a3303a0a1ae4264d74ed6c24b7533a9e..eec536aef83a5bdf67add50b72e44685ea2df33d 100644 (file)
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -94,7 +94,7 @@ int main(void)
        OFFSET(TASK_CPU, task_struct, thread_info.cpu);
 #endif
 
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
        OFFSET(TI_livepatch_sp, thread_info, livepatch_sp);
 #endif