From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Jordan Niethe <jniethe5@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: ajd@linux.ibm.com, npiggin@gmail.com, cmr@codefail.de,
aneesh.kumar@linux.ibm.com, naveen.n.rao@linux.ibm.com,
dja@axtens.net
Subject: Re: [PATCH v11 3/9] powerpc: Always define MODULES_{VADDR,END}
Date: Thu, 29 Apr 2021 07:04:08 +0200 [thread overview]
Message-ID: <111c8736-fff9-ba0a-4749-f9388b32c9bf@csgroup.eu> (raw)
In-Reply-To: <20210429031602.2606654-4-jniethe5@gmail.com>
Le 29/04/2021 à 05:15, Jordan Niethe a écrit :
> If MODULES_{VADDR,END} are not defined set them to VMALLOC_START and
> VMALLOC_END respectively. This reduces the need for special cases. For
> example, powerpc's module_alloc() was previously predicated on
> MODULES_VADDR being defined but now is unconditionally defined.
>
> This will be useful reducing conditional code in other places that need
> to allocate from the module region (i.e., kprobes).
>
> Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
> ---
> v10: New to series
> v11: - Consider more places MODULES_VADDR was being used
> ---
> arch/powerpc/include/asm/pgtable.h | 11 +++++++++++
> arch/powerpc/kernel/module.c | 5 +----
> arch/powerpc/mm/kasan/kasan_init_32.c | 10 +++++-----
> arch/powerpc/mm/ptdump/ptdump.c | 4 ++--
> 4 files changed, 19 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> index c6a676714f04..882fda779648 100644
> --- a/arch/powerpc/include/asm/pgtable.h
> +++ b/arch/powerpc/include/asm/pgtable.h
> @@ -39,6 +39,17 @@ struct mm_struct;
> #define __S110 PAGE_SHARED_X
> #define __S111 PAGE_SHARED_X
>
> +#ifndef MODULES_VADDR
> +#define MODULES_VADDR VMALLOC_START
> +#define MODULES_END VMALLOC_END
> +#endif
> +
> +#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_STRICT_KERNEL_RWX)
No no.
TASK_SIZE > MODULES_VADDR is ALWAYS wrong, for any target, in any configuration.
Why is it a problem to leave the test as a BUILD_BUG_ON() in module_alloc() ?
> +#if TASK_SIZE > MODULES_VADDR
> +#error TASK_SIZE > MODULES_VADDR
> +#endif
> +#endif
> +
> #ifndef __ASSEMBLY__
>
> /* Keep these as a macros to avoid include dependency mess */
> diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
> index fab84024650c..c60c7457ff47 100644
> --- a/arch/powerpc/kernel/module.c
> +++ b/arch/powerpc/kernel/module.c
> @@ -15,6 +15,7 @@
> #include <linux/sort.h>
> #include <asm/setup.h>
> #include <asm/sections.h>
> +#include <linux/mm.h>
>
> static LIST_HEAD(module_bug_list);
>
> @@ -88,7 +89,6 @@ int module_finalize(const Elf_Ehdr *hdr,
> return 0;
> }
>
> -#ifdef MODULES_VADDR
> static __always_inline void *
> __module_alloc(unsigned long size, unsigned long start, unsigned long end)
> {
> @@ -102,8 +102,6 @@ void *module_alloc(unsigned long size)
> unsigned long limit = (unsigned long)_etext - SZ_32M;
> void *ptr = NULL;
>
> - BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
> -
> /* First try within 32M limit from _etext to avoid branch trampolines */
> if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit)
> ptr = __module_alloc(size, limit, MODULES_END);
> @@ -113,4 +111,3 @@ void *module_alloc(unsigned long size)
>
> return ptr;
> }
> -#endif
> diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
> index cf8770b1a692..42c057366ac7 100644
> --- a/arch/powerpc/mm/kasan/kasan_init_32.c
> +++ b/arch/powerpc/mm/kasan/kasan_init_32.c
> @@ -116,11 +116,11 @@ static void __init kasan_unmap_early_shadow_vmalloc(void)
>
> kasan_update_early_region(k_start, k_end, __pte(0));
>
> -#ifdef MODULES_VADDR
> - k_start = (unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR);
> - k_end = (unsigned long)kasan_mem_to_shadow((void *)MODULES_END);
> - kasan_update_early_region(k_start, k_end, __pte(0));
> -#endif
> + if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
Shouldn't it be an || ?
As soon as either MODULES_VADDR or MODULES_END differs from the vmalloc boundaries, it needs to be
done I think.
> + k_start = (unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR);
> + k_end = (unsigned long)kasan_mem_to_shadow((void *)MODULES_END);
> + kasan_update_early_region(k_start, k_end, __pte(0));
> + }
> }
>
> void __init kasan_mmu_init(void)
> diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
> index aca354fb670b..0431457f668f 100644
> --- a/arch/powerpc/mm/ptdump/ptdump.c
> +++ b/arch/powerpc/mm/ptdump/ptdump.c
> @@ -73,7 +73,7 @@ struct addr_marker {
>
> static struct addr_marker address_markers[] = {
> { 0, "Start of kernel VM" },
> -#ifdef MODULES_VADDR
> +#if defined(CONFIG_BOOK32_32) && defined(CONFIG_STRICT_KERNEL_RWX)
Not valid anymore, see https://github.com/linuxppc/linux/commit/80edc68e0479 and
https://github.com/linuxppc/linux/commit/9132a2e82adc
The best would be to be able to do something like:
#if MODULES_VADDR != VMALLOC_START
If it doesn't work, then it has to be
#if defined(CONFIG_BOOK32_32) || defined(CONFIG_PPC_8xx)
> { 0, "modules start" },
> { 0, "modules end" },
> #endif
> @@ -359,7 +359,7 @@ static void populate_markers(void)
> #else
> address_markers[i++].start_address = TASK_SIZE;
> #endif
> -#ifdef MODULES_VADDR
> +#if defined(CONFIG_BOOK32_32) && defined(CONFIG_STRICT_KERNEL_RWX)
Same.
> address_markers[i++].start_address = MODULES_VADDR;
> address_markers[i++].start_address = MODULES_END;
> #endif
>
next prev parent reply other threads:[~2021-04-29 5:04 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 3:15 [PATCH v11 0/9] powerpc: Further Strict RWX support Jordan Niethe
2021-04-29 3:15 ` [PATCH v11 1/9] powerpc/mm: Implement set_memory() routines Jordan Niethe
2021-04-29 7:32 ` Christophe Leroy
2021-05-03 5:02 ` Jordan Niethe
2021-04-29 3:15 ` [PATCH v11 2/9] powerpc/lib/code-patching: Set up Strict RWX patching earlier Jordan Niethe
2021-04-29 4:53 ` Christophe Leroy
2021-05-05 5:22 ` Jordan Niethe
2021-04-29 3:15 ` [PATCH v11 3/9] powerpc: Always define MODULES_{VADDR,END} Jordan Niethe
2021-04-29 5:04 ` Christophe Leroy [this message]
2021-05-03 5:39 ` Jordan Niethe
2021-05-03 5:57 ` Christophe Leroy
2021-05-03 6:16 ` Jordan Niethe
2021-05-03 6:22 ` Christophe Leroy
2021-05-03 6:26 ` Jordan Niethe
2021-05-03 6:32 ` Christophe Leroy
2021-04-29 3:15 ` [PATCH v11 4/9] powerpc/kprobes: Mark newly allocated probes as ROX Jordan Niethe
2021-04-29 3:15 ` [PATCH v11 5/9] powerpc/bpf: Remove bpf_jit_free() Jordan Niethe
2021-04-29 3:15 ` [PATCH v11 6/9] powerpc/bpf: Write protect JIT code Jordan Niethe
2021-04-29 3:16 ` [PATCH v11 7/9] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX Jordan Niethe
2021-04-29 3:16 ` [PATCH v11 8/9] powerpc/mm: implement set_memory_attr() Jordan Niethe
2021-04-29 3:16 ` [PATCH v11 9/9] powerpc/32: use set_memory_attr() Jordan Niethe
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