On Mon, Dec 14, 2015 at 05:00:59PM -0800, Luck, Tony wrote:
> Not sure what the "whatnot" would be though. Making it depend on
> X86_MCE should keep it out of the tiny configurations. By the time
> you have MCE support, this seems like a pretty small incremental
> change.
Ok, so it is called CONFIG_LIBNVDIMM. Do you see a use case for this
stuff except on machines with NVDIMM hw? CONFIG_LIBNVDIMM can select it
but on !NVDIMM systems you don't really need it enabled.
> Is there some cpp magic to use an #ifdef inside a multi-line macro like this?
> Impact of not having the #ifdef is two extra symbols (the start/stop ones)
> in the symbol table of the final binary. If that's unacceptable I can fall
> back to an earlier unpublished version that had separate EXCEPTION_TABLE and
> MCEXCEPTION_TABLE macros with both invoked in the x86 vmlinux.lds.S file.
I think what is more important is that this should be in the
x86-specific linker script, not in the generic one. And yes, we should
strive to be clean and not pullute the kernel image with symbols which
are unused, i.e. when CONFIG_MCE_KERNEL_RECOVERY is not enabled.
This below seems to build ok here, ontop of yours. It could be a
MCEXCEPTION_TABLE macro, as you say:
Index: b/include/asm-generic/vmlinux.lds.h
===================================================================
--- a/include/asm-generic/vmlinux.lds.h 2015-12-15 10:17:25.568046033 +0100
+++ b/include/asm-generic/vmlinux.lds.h 2015-12-15 10:07:06.064034490 +0100
@@ -484,12 +484,6 @@
*(__ex_table) \
VMLINUX_SYMBOL(__stop___ex_table) = .; \
} \
- . = ALIGN(align); \
- __mcex_table : AT(ADDR(__mcex_table) - LOAD_OFFSET) { \
- VMLINUX_SYMBOL(__start___mcex_table) = .; \
- *(__mcex_table) \
- VMLINUX_SYMBOL(__stop___mcex_table) = .; \
- }
/*
* Init task
Index: b/arch/x86/kernel/vmlinux.lds.S
===================================================================
--- a/arch/x86/kernel/vmlinux.lds.S 2015-12-14 11:38:58.188150070 +0100
+++ b/arch/x86/kernel/vmlinux.lds.S 2015-12-15 10:09:04.624036699 +0100
@@ -110,7 +110,17 @@ SECTIONS
NOTES :text :note
- EXCEPTION_TABLE(16) :text = 0x9090
+ EXCEPTION_TABLE(16)
+
+#ifdef CONFIG_MCE_KERNEL_RECOVERY
+ . = ALIGN(16);
+ __mcex_table : AT(ADDR(__mcex_table) - LOAD_OFFSET) {
+ VMLINUX_SYMBOL(__start___mcex_table) = .;
+ *(__mcex_table)
+ VMLINUX_SYMBOL(__stop___mcex_table) = .;
+ }
+#endif
+ :text = 0x9090
#if defined(CONFIG_DEBUG_RODATA)
/* .text should occupy whole number of pages */
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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