On Sun, 5 Aug 2012, Cyril Chemparathy wrote: > Hi Nicolas, > > On 8/4/2012 2:15 AM, Nicolas Pitre wrote: > > On Tue, 31 Jul 2012, Cyril Chemparathy wrote: > > > > > This patch replaces the original physical offset patching implementation > > > with one that uses the newly added patching framework. In the process, we > > > now > > > unconditionally initialize the __pv_phys_offset and __pv_offset globals in > > > the > > > head.S code. > > > > Why unconditionally initializing those? There is no reason for that. > > > > We could keep this conditional on LPAE, but do you see any specific need for > keeping it conditional?
This has nothing to do with LPAe. This is about CONFIG_ARM_PATCH_PHYS_VIRT only. If not selected, those global vaariables have no need to exist. > > Comments below. > > > > > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > > > index 835898e..d165896 100644 > > > --- a/arch/arm/kernel/head.S > > > +++ b/arch/arm/kernel/head.S > > [...] > > > .data > > > .globl __pv_phys_offset > > > .type __pv_phys_offset, %object > > > __pv_phys_offset: > > > .long 0 > > > .size __pv_phys_offset, . - __pv_phys_offset > > > + > > > + .globl __pv_offset > > > + .type __pv_offset, %object > > > __pv_offset: > > > .long 0 > > > -#endif > > > + .size __pv_offset, . - __pv_offset > > > > Please move those to C code. They aren't of much use in this file > > anymore. This will allow you to use pphys_addr_t for them as well in > > your subsequent patch. And more importantly get rid of that ugly > > pv_offset_high that you introduced iin another patch. > > > > Moving it to C-code caused problems because these get filled in prior to BSS > being cleared. > > We could potentially have this initialized in C with a mystery dummy value to > prevent it from landing in BSS. Would that be acceptable? Just initialize them explicitly to zero. They will end up in .ddata section. > > > > index df5e897..39f8fce 100644 > > > --- a/arch/arm/kernel/module.c > > > +++ b/arch/arm/kernel/module.c > > > @@ -317,11 +317,6 @@ int module_finalize(const Elf32_Ehdr *hdr, const > > > Elf_Shdr *sechdrs, > > > > > > maps[i].txt_sec->sh_addr, > > > > > > maps[i].txt_sec->sh_size); > > > #endif > > > -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT > > > - s = find_mod_section(hdr, sechdrs, ".pv_table"); > > > - if (s) > > > - fixup_pv_table((void *)s->sh_addr, s->sh_size); > > > -#endif > > > s = find_mod_section(hdr, sechdrs, ".patch.table"); > > > if (s) > > > patch_kernel((void *)s->sh_addr, s->sh_size); > > > > The patch_kernel code and its invokation should still be conditional on > > CONFIG_ARM_PATCH_PHYS_VIRT. This ability may still be configured out > > irrespective of the implementation used. > > > > Maybe CONFIG_ARM_PATCH_PHYS_VIRT is not quite appropriate if this is used to > patch up other things in addition to phys-virt stuff? Maybe, but at the moment this is not the case. > I could have this dependent on CONFIG_ARM_INIT_PATCH (or whatever nomenclature > we chose for this) and have CONFIG_ARM_PATCH_PHYS_VIRT depend on it. Let's cross that bridge in time. FWIW, I don't like "init patch" much. I feel like the "runtime" qualifier more pricisely describe this code than "init". Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
