Re: [PATCH 10/10] powerpc: select DYNAMIC_DEBUG_RELATIVE_POINTERS for PPC64

From: Christophe Leroy
Date: Tue Apr 23 2019 - 11:37:39 EST




Le 09/04/2019 Ã 23:25, Rasmus Villemoes a ÃcritÂ:
Similar to GENERIC_BUG_RELATIVE_POINTERS, one can now relativize the
four const char* members of struct _ddebug, thus saving 16 bytes per
instance (one for each pr_debug(), dev_debug() etc. in a
CONFIG_DYNAMIC_DEBUG kernel). The asm-generic implementation seems to
work out-of-the-box, though this is only compile-tested.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/Kbuild | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2d0be82c3061..6821c8ae1d62 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -155,6 +155,7 @@ config PPC
select BUILDTIME_EXTABLE_SORT
select CLONE_BACKWARDS
select DCACHE_WORD_ACCESS if PPC64 && CPU_LITTLE_ENDIAN
+ select DYNAMIC_DEBUG_RELATIVE_POINTERS if PPC64

Why only PPC64 ? Won't it work with PPC32 ? Or would it be counter-performant on 32 bits ?

Christophe

select DYNAMIC_FTRACE if FUNCTION_TRACER
select EDAC_ATOMIC_SCRUB
select EDAC_SUPPORT
diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index a0c132bedfae..f332e202192a 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild
@@ -3,6 +3,7 @@ generated-y += syscall_table_64.h
generated-y += syscall_table_c32.h
generated-y += syscall_table_spu.h
generic-y += div64.h
+generic-y += dynamic_debug.h
generic-y += export.h
generic-y += irq_regs.h
generic-y += local64.h