6.15-stable review patch. If anyone has any objections, please let me know.
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From: Mike Rapoport (Microsoft) rppt@kernel.org
commit 7cd9a11dd0c3d1dd225795ed1b5b53132888e7b5 upstream.
The commit d6d1e3e6580c ("mm/execmem: Unify early execmem_cache behaviour") changed early behaviour of execemem ROX cache to allow its usage in early x86 code that allocates text pages when CONFIG_MITGATION_ITS is enabled.
The permission management of the pages allocated from execmem for ITS mitigation is now completely contained in arch/x86/kernel/alternatives.c and therefore there is no need to special case early allocations in execmem.
This reverts commit d6d1e3e6580ca35071ad474381f053cbf1fb6414.
Signed-off-by: Mike Rapoport (Microsoft) rppt@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20250603111446.2609381-6-rppt@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/mm/init_32.c | 3 --- arch/x86/mm/init_64.c | 3 --- include/linux/execmem.h | 8 +------- mm/execmem.c | 40 +++------------------------------------- 4 files changed, 4 insertions(+), 50 deletions(-)
--- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -30,7 +30,6 @@ #include <linux/initrd.h> #include <linux/cpumask.h> #include <linux/gfp.h> -#include <linux/execmem.h>
#include <asm/asm.h> #include <asm/bios_ebda.h> @@ -756,8 +755,6 @@ void mark_rodata_ro(void) pr_info("Write protecting kernel text and read-only data: %luk\n", size >> 10);
- execmem_cache_make_ro(); - kernel_set_to_readonly = 1;
#ifdef CONFIG_CPA_DEBUG --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -34,7 +34,6 @@ #include <linux/gfp.h> #include <linux/kcore.h> #include <linux/bootmem_info.h> -#include <linux/execmem.h>
#include <asm/processor.h> #include <asm/bios_ebda.h> @@ -1392,8 +1391,6 @@ void mark_rodata_ro(void) (end - start) >> 10); set_memory_ro(start, (end - start) >> PAGE_SHIFT);
- execmem_cache_make_ro(); - kernel_set_to_readonly = 1;
/* --- a/include/linux/execmem.h +++ b/include/linux/execmem.h @@ -54,7 +54,7 @@ enum execmem_range_flags { EXECMEM_ROX_CACHE = (1 << 1), };
-#if defined(CONFIG_ARCH_HAS_EXECMEM_ROX) && defined(CONFIG_EXECMEM) +#ifdef CONFIG_ARCH_HAS_EXECMEM_ROX /** * execmem_fill_trapping_insns - set memory to contain instructions that * will trap @@ -94,15 +94,9 @@ int execmem_make_temp_rw(void *ptr, size * Return: 0 on success or negative error code on failure. */ int execmem_restore_rox(void *ptr, size_t size); - -/* - * Called from mark_readonly(), where the system transitions to ROX. - */ -void execmem_cache_make_ro(void); #else static inline int execmem_make_temp_rw(void *ptr, size_t size) { return 0; } static inline int execmem_restore_rox(void *ptr, size_t size) { return 0; } -static inline void execmem_cache_make_ro(void) { } #endif
/** --- a/mm/execmem.c +++ b/mm/execmem.c @@ -254,34 +254,6 @@ out_unlock: return ptr; }
-static bool execmem_cache_rox = false; - -void execmem_cache_make_ro(void) -{ - struct maple_tree *free_areas = &execmem_cache.free_areas; - struct maple_tree *busy_areas = &execmem_cache.busy_areas; - MA_STATE(mas_free, free_areas, 0, ULONG_MAX); - MA_STATE(mas_busy, busy_areas, 0, ULONG_MAX); - struct mutex *mutex = &execmem_cache.mutex; - void *area; - - execmem_cache_rox = true; - - mutex_lock(mutex); - - mas_for_each(&mas_free, area, ULONG_MAX) { - unsigned long pages = mas_range_len(&mas_free) >> PAGE_SHIFT; - set_memory_ro(mas_free.index, pages); - } - - mas_for_each(&mas_busy, area, ULONG_MAX) { - unsigned long pages = mas_range_len(&mas_busy) >> PAGE_SHIFT; - set_memory_ro(mas_busy.index, pages); - } - - mutex_unlock(mutex); -} - static int execmem_cache_populate(struct execmem_range *range, size_t size) { unsigned long vm_flags = VM_ALLOW_HUGE_VMAP; @@ -302,15 +274,9 @@ static int execmem_cache_populate(struct /* fill memory with instructions that will trap */ execmem_fill_trapping_insns(p, alloc_size, /* writable = */ true);
- if (execmem_cache_rox) { - err = set_memory_rox((unsigned long)p, vm->nr_pages); - if (err) - goto err_free_mem; - } else { - err = set_memory_x((unsigned long)p, vm->nr_pages); - if (err) - goto err_free_mem; - } + err = set_memory_rox((unsigned long)p, vm->nr_pages); + if (err) + goto err_free_mem;
err = execmem_cache_add(p, alloc_size); if (err)