tmakin/tegra-linux-noble
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

arm64: module: remove old !KASAN_VMALLOC logic

Browse Source 
Historically, KASAN could be selected with or without KASAN_VMALLOC, and
we had to be very careful where to place modules when KASAN_VMALLOC was
not selected.

However, since commit:

  f6f37d9320 ("arm64: select KASAN_VMALLOC for SW/HW_TAGS modes")

Selecting CONFIG_KASAN on arm64 will also select CONFIG_KASAN_VMALLOC,
and so the logic for handling CONFIG_KASAN without CONFIG_KASAN_VMALLOC
is redundant and can be removed.

Note: the "kasan.vmalloc={on,off}" option which only exists for HW_TAGS
changes whether the vmalloc region is given non-match-all tags, and does
not affect the page table manipulation code.

The VM_DEFER_KMEMLEAK flag was only necessary for !CONFIG_KASAN_VMALLOC
as described in its introduction in commit:

  60115fa54a ("mm: defer kmemleak object creation of module_alloc()")

... and therefore it can also be removed.

Remove the redundant logic for !CONFIG_KASAN_VMALLOC. At the same time,
add the missing braces around the multi-line conditional block in
arch/arm64/kernel/module.c.

Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will@kernel.org>
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com>
Link: https://lore.kernel.org/r/20230530110328.2213762-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland
2023-05-30 12:03:23 +01:00
committed by Catalin Marinas
parent 44c026a73b
commit 8339f7d8e1
2 changed files with 3 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm64/kernel/kaslr.c
-10
View File
@@ -48,16 +48,6 @@ static int __init kaslr_init(void)
pr_info("KASLR enabled\n");
/*
* KASAN without KASAN_VMALLOC does not expect the module region to
* intersect the vmalloc region, since shadow memory is allocated for
* each module at load time, whereas the vmalloc region will already be
* shadowed by KASAN zero pages.
*/
BUILD_BUG_ON((IS_ENABLED(CONFIG_KASAN_GENERIC) ||
IS_ENABLED(CONFIG_KASAN_SW_TAGS)) &&
!IS_ENABLED(CONFIG_KASAN_VMALLOC));
seed = get_random_u32();
if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) {
arch/arm64/kernel/module.c
+3 -20
View File
@@ -32,33 +32,16 @@ void *module_alloc(unsigned long size)
if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
gfp_mask |= __GFP_NOWARN;
if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
IS_ENABLED(CONFIG_KASAN_SW_TAGS))
/* don't exceed the static module region - see below */
module_alloc_end = MODULES_END;
p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
module_alloc_end, gfp_mask, PAGE_KERNEL, 0,
NUMA_NO_NODE, __builtin_return_address(0));
if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
(IS_ENABLED(CONFIG_KASAN_VMALLOC) ||
(!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
!IS_ENABLED(CONFIG_KASAN_SW_TAGS))))
/*
* KASAN without KASAN_VMALLOC can only deal with module
* allocations being served from the reserved module region,
* since the remainder of the vmalloc region is already
* backed by zero shadow pages, and punching holes into it
* is non-trivial. Since the module region is not randomized
* when KASAN is enabled without KASAN_VMALLOC, it is even
* less likely that the module region gets exhausted, so we
* can simply omit this fallback in that case.
*/
if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)) {
p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
module_alloc_base + SZ_2G, GFP_KERNEL,
PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
}
if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
vfree(p);