Le 30/11/2020 à 02:50, Jordan Niethe a écrit :
On Mon, Nov 30, 2020 at 12:42 PM Michael Ellerman <m...@ellerman.id.au> wrote:
Christophe Leroy <christophe.le...@csgroup.eu> writes:
Le 27/11/2020 à 04:02, Jordan Niethe a écrit :
This enables GENERIC_BUG_RELATIVE_POINTERS on Power so that 32-bit
offsets are stored in the bug entries rather than 64-bit pointers.
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
---
arch/powerpc/Kconfig | 4 ++++
arch/powerpc/include/asm/bug.h | 37 ++++++++++++++++++++++++++++++++--
arch/powerpc/xmon/xmon.c | 17 ++++++++++++++--
3 files changed, 54 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e9f13fe08492..294108e0e5c6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -311,6 +311,10 @@ config GENERIC_BUG
default y
depends on BUG
+config GENERIC_BUG_RELATIVE_POINTERS
+ def_bool y
+ depends on GENERIC_BUG
+
config SYS_SUPPORTS_APM_EMULATION
default y if PMAC_APM_EMU
bool
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 338f36cd9934..d03d834042a1 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -12,7 +12,11 @@
#ifdef CONFIG_DEBUG_BUGVERBOSE
.macro EMIT_BUG_ENTRY addr,file,line,flags
.section __bug_table,"aw"
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
As far as I understand, as soon as CONFIG_BUG is selected, GENERIC_BUG is
automatically selected so
GENERIC_BUG_RELATIVE_POINTERS is selected as well. Therefore this #ifndef is
never possible.
Yeah.
There is one place in the generic code that has an ifndef
CONFIG_GENERIC_BUG_RELATIVE_POINTERS
but that's because it has to support arches that don't select it.
In the arch code we know that it's enabled, so there should be no need
for any ifdefs.
For 32bit, pointers are 4 bytes anyway so it would be pointless to
store a displacement, so won't we need some ifdefs for that?
I'd say it the other way round:
For 32bit, pointers are 4 bytes anyway so it would be pointless to
make it different from 64bit.
We are definitely not on a performance critical path when dealing with bug entries, so I think it is
better to keep a common code for PPC32 and PPC64.
Christophe
