From: Oliver Upton <oliver.upton@linux.dev>
Date: Thu, 15 Jun 2023 13:04:10 +0000 (+0000)
Subject: Merge branch for-next/module-alloc into kvmarm/next
X-Git-Tag: v6.6.7~2444^2~7^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=acfdf34c7de19e1ee9ce3ea2d47e2bf11620f910;p=platform%2Fkernel%2Flinux-starfive.git

Merge branch for-next/module-alloc into kvmarm/next

* for-next/module-alloc:
  : Drag in module VA rework to handle conflicts w/ sw feature refactor
  arm64: module: rework module VA range selection
  arm64: module: mandate MODULE_PLTS
  arm64: module: move module randomization to module.c
  arm64: kaslr: split kaslr/module initialization
  arm64: kasan: remove !KASAN_VMALLOC remnants
  arm64: module: remove old !KASAN_VMALLOC logic

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---

acfdf34c7de19e1ee9ce3ea2d47e2bf11620f910
diff --cc arch/arm64/kernel/kaslr.c
index 5d4ce7f,17f96a1..94a269c
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@@ -4,90 -4,35 +4,35 @@@
   */
  
  #include <linux/cache.h>
- #include <linux/crc32.h>
  #include <linux/init.h>
- #include <linux/libfdt.h>
- #include <linux/mm_types.h>
- #include <linux/sched.h>
- #include <linux/types.h>
- #include <linux/pgtable.h>
- #include <linux/random.h>
+ #include <linux/printk.h>
  
- #include <asm/fixmap.h>
- #include <asm/kernel-pgtable.h>
+ #include <asm/cpufeature.h>
  #include <asm/memory.h>
- #include <asm/mmu.h>
- #include <asm/sections.h>
- #include <asm/setup.h>
  
- u64 __ro_after_init module_alloc_base;
  u16 __initdata memstart_offset_seed;
  
- static int __init kaslr_init(void)
- {
- 	u64 module_range;
- 	u32 seed;
 -struct arm64_ftr_override kaslr_feature_override __initdata;
--
- 	/*
- 	 * Set a reasonable default for module_alloc_base in case
- 	 * we end up running with module randomization disabled.
- 	 */
- 	module_alloc_base = (u64)_etext - MODULES_VSIZE;
+ bool __ro_after_init __kaslr_is_enabled = false;
  
+ void __init kaslr_init(void)
+ {
 -	if (kaslr_feature_override.val & kaslr_feature_override.mask & 0xf) {
 +	if (cpuid_feature_extract_unsigned_field(arm64_sw_feature_override.val &
 +						 arm64_sw_feature_override.mask,
 +						 ARM64_SW_FEATURE_OVERRIDE_NOKASLR)) {
  		pr_info("KASLR disabled on command line\n");
- 		return 0;
- 	}
- 
- 	if (!kaslr_enabled()) {
- 		pr_warn("KASLR disabled due to lack of seed\n");
- 		return 0;
+ 		return;
  	}
  
- 	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.
+ 	 * The KASLR offset modulo MIN_KIMG_ALIGN is taken from the physical
+ 	 * placement of the image rather than from the seed, so a displacement
+ 	 * of less than MIN_KIMG_ALIGN means that no seed was provided.
  	 */
- 	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)) {
- 		/*
- 		 * Randomize the module region over a 2 GB window covering the
- 		 * kernel. This reduces the risk of modules leaking information
- 		 * about the address of the kernel itself, but results in
- 		 * branches between modules and the core kernel that are
- 		 * resolved via PLTs. (Branches between modules will be
- 		 * resolved normally.)
- 		 */
- 		module_range = SZ_2G - (u64)(_end - _stext);
- 		module_alloc_base = max((u64)_end - SZ_2G, (u64)MODULES_VADDR);
- 	} else {
- 		/*
- 		 * Randomize the module region by setting module_alloc_base to
- 		 * a PAGE_SIZE multiple in the range [_etext - MODULES_VSIZE,
- 		 * _stext) . This guarantees that the resulting region still
- 		 * covers [_stext, _etext], and that all relative branches can
- 		 * be resolved without veneers unless this region is exhausted
- 		 * and we fall back to a larger 2GB window in module_alloc()
- 		 * when ARM64_MODULE_PLTS is enabled.
- 		 */
- 		module_range = MODULES_VSIZE - (u64)(_etext - _stext);
+ 	if (kaslr_offset() < MIN_KIMG_ALIGN) {
+ 		pr_warn("KASLR disabled due to lack of seed\n");
+ 		return;
  	}
  
- 	/* use the lower 21 bits to randomize the base of the module region */
- 	module_alloc_base += (module_range * (seed & ((1 << 21) - 1))) >> 21;
- 	module_alloc_base &= PAGE_MASK;
- 
- 	return 0;
+ 	pr_info("KASLR enabled\n");
+ 	__kaslr_is_enabled = true;
  }
- subsys_initcall(kaslr_init)