From: cyril@ti•com (Cyril Chemparathy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 02/22] ARM: use late patch framework for phys-virt patching
Date: Sun, 5 Aug 2012 10:03:45 -0400 [thread overview]
Message-ID: <501E7D41.8070303@ti.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1208040138560.5231@xanadu.home>
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?
>> Signed-off-by: Cyril Chemparathy <cyril@ti•com>
>
> 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?
>> diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
>> 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?
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.
>> diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
>> index bacb275..13731e3 100644
>> --- a/arch/arm/kernel/vmlinux.lds.S
>> +++ b/arch/arm/kernel/vmlinux.lds.S
>> @@ -162,11 +162,6 @@ SECTIONS
>> __smpalt_end = .;
>> }
>> #endif
>> - .init.pv_table : {
>> - __pv_table_begin = .;
>> - *(.pv_table)
>> - __pv_table_end = .;
>> - }
>> .init.patch_table : {
>> __patch_table_begin = .;
>> *(.patch.table)
>
> Since you're changing the module ABI,it is important to also modify the
> module vermagic string in asm/module.h to prevent the loading of
> incompatible kernel modules.
>
Absolutely. Thanks.
>
> Nicolas
>
--
Thanks
- Cyril
next prev parent reply other threads:[~2012-08-05 14:03 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-31 23:04 [PATCH 00/22] Introducing the TI Keystone platform Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 01/22] ARM: add mechanism for late code patching Cyril Chemparathy
2012-08-04 5:38 ` Nicolas Pitre
2012-08-05 13:56 ` Cyril Chemparathy
2012-08-07 22:52 ` Cyril Chemparathy
2012-08-08 5:56 ` Nicolas Pitre
2012-08-08 13:18 ` Cyril Chemparathy
2012-08-08 13:55 ` Nicolas Pitre
2012-08-08 16:05 ` Russell King - ARM Linux
2012-08-08 16:56 ` Nicolas Pitre
2012-08-09 6:59 ` Tixy
2012-08-06 11:12 ` Russell King - ARM Linux
2012-08-06 13:19 ` Cyril Chemparathy
2012-08-06 13:26 ` Russell King - ARM Linux
2012-08-06 13:38 ` Cyril Chemparathy
2012-08-06 18:02 ` Nicolas Pitre
2012-07-31 23:04 ` [PATCH 02/22] ARM: use late patch framework for phys-virt patching Cyril Chemparathy
2012-08-04 6:15 ` Nicolas Pitre
2012-08-05 14:03 ` Cyril Chemparathy [this message]
2012-08-06 2:06 ` Nicolas Pitre
2012-07-31 23:04 ` [PATCH 03/22] ARM: LPAE: use phys_addr_t on virt <--> phys conversion Cyril Chemparathy
2012-08-04 6:24 ` Nicolas Pitre
2012-08-05 14:05 ` Cyril Chemparathy
2012-08-06 11:14 ` Russell King - ARM Linux
2012-08-06 13:30 ` Cyril Chemparathy
2012-08-09 14:10 ` Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 04/22] ARM: LPAE: support 64-bit virt/phys patching Cyril Chemparathy
2012-08-04 6:49 ` Nicolas Pitre
2012-08-05 14:21 ` Cyril Chemparathy
2012-08-06 2:19 ` Nicolas Pitre
2012-07-31 23:04 ` [PATCH 05/22] ARM: LPAE: use signed arithmetic for mask definitions Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 06/22] ARM: LPAE: use phys_addr_t in alloc_init_pud() Cyril Chemparathy
2012-08-01 12:08 ` Sergei Shtylyov
2012-08-01 15:42 ` Cyril Chemparathy
2012-08-04 6:51 ` Nicolas Pitre
2012-07-31 23:04 ` [PATCH 07/22] ARM: LPAE: use phys_addr_t in free_memmap() Cyril Chemparathy
2012-08-04 6:54 ` Nicolas Pitre
2012-07-31 23:04 ` [PATCH 08/22] ARM: LPAE: use phys_addr_t for initrd location and size Cyril Chemparathy
2012-08-04 6:57 ` Nicolas Pitre
2012-08-05 14:23 ` Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 09/22] ARM: LPAE: use 64-bit pgd physical address in switch_mm() Cyril Chemparathy
2012-08-04 7:04 ` Nicolas Pitre
2012-08-05 14:29 ` Cyril Chemparathy
2012-08-06 2:35 ` Nicolas Pitre
2012-07-31 23:04 ` [PATCH 10/22] ARM: LPAE: use 64-bit accessors for TTBR registers Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 11/22] ARM: LPAE: define ARCH_LOW_ADDRESS_LIMIT for bootmem Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 12/22] ARM: LPAE: factor out T1SZ and TTBR1 computations Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 13/22] ARM: LPAE: allow proc override of TTB setup Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 14/22] ARM: LPAE: accomodate >32-bit addresses for page table base Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 15/22] ARM: mm: use physical addresses in highmem sanity checks Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 16/22] ARM: mm: cleanup checks for membank overlap with vmalloc area Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 17/22] ARM: mm: clean up membank size limit checks Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 18/22] ARM: add virt_to_idmap for interconnect aliasing Cyril Chemparathy
2012-07-31 23:04 ` [PATCH 19/22] ARM: recreate kernel mappings in early_paging_init() Cyril Chemparathy
2012-07-31 23:05 ` [RFC 21/22] ARM: keystone: enable SMP on Keystone machines Cyril Chemparathy
2012-07-31 23:05 ` [RFC 22/22] ARM: keystone: add switch over to high physical address range Cyril Chemparathy
2012-07-31 23:06 ` [RFC 20/22] ARM: keystone: introducing TI Keystone platform Cyril Chemparathy
2012-07-31 23:16 ` Arnd Bergmann
2012-08-01 15:41 ` Cyril Chemparathy
2012-08-01 17:20 ` Arnd Bergmann
2012-08-04 8:39 ` [PATCH 00/22] Introducing the " Russell King - ARM Linux
2012-08-05 15:10 ` Cyril Chemparathy
2012-08-08 15:43 ` Catalin Marinas
2012-08-08 13:57 ` Will Deacon
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