[PATCH v2 0/6] powerpc/32s: Allocate modules outside of vmalloc space for STRICT_KERNEL_RWX

@@ -86,3 +86,14 @@ int module_finalize(const Elf_Ehdr *hdr,
 
 	return 0;
 }
+
+#ifdef MODULES_VADDR
+void *module_alloc(unsigned long size)
+{
+	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
+
+	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, GFP_KERNEL,
+				    PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
+				    __builtin_return_address(0));
+}
+#endif

@@ -115,6 +115,12 @@ static void __init kasan_unmap_early_shadow_vmalloc(void)
 	unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END);
 
 	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
 }
 
 static void __init kasan_mmu_init(void)

@@ -255,8 +255,10 @@ static inline bool pfn_valid(unsigned long pfn)
  */
 #ifdef CONFIG_PPC_BOOK3E_64
 #define is_kernel_addr(x)	((x) >= 0x8000000000000000ul)
-#else
+#elif defined(CONFIG_PPC_BOOK3S_64)
 #define is_kernel_addr(x)	((x) >= PAGE_OFFSET)
+#else
+#define is_kernel_addr(x)	((x) >= TASK_SIZE)
 #endif
 
 #ifndef CONFIG_PPC_BOOK3S_64

@@ -348,7 +348,11 @@ static void populate_markers(void)
 {
 	int i = 0;
 
+#ifdef CONFIG_PPC64
 	address_markers[i++].start_address = PAGE_OFFSET;
+#else
+	address_markers[i++].start_address = TASK_SIZE;
+#endif
 	address_markers[i++].start_address = VMALLOC_START;
 	address_markers[i++].start_address = VMALLOC_END;
 #ifdef CONFIG_PPC64

@@ -385,7 +389,7 @@ static int ptdump_show(struct seq_file *m, void *v)
 	struct pg_state st = {
 		.seq = m,
 		.marker = address_markers,
-		.start_address = PAGE_OFFSET,
+		.start_address = IS_ENABLED(CONFIG_PPC64) ? PAGE_OFFSET : TASK_SIZE,
 	};
 
 #ifdef CONFIG_PPC64

@@ -429,7 +433,7 @@ void ptdump_check_wx(void)
 		.seq = NULL,
 		.marker = address_markers,
 		.check_wx = true,
-		.start_address = PAGE_OFFSET,
+		.start_address = IS_ENABLED(CONFIG_PPC64) ? PAGE_OFFSET : TASK_SIZE,
 	};
 
 #ifdef CONFIG_PPC64

@@ -1194,6 +1194,7 @@ config TASK_SIZE_BOOL
 config TASK_SIZE
 	hex "Size of user task space" if TASK_SIZE_BOOL
 	default "0x80000000" if PPC_8xx
+	default "0xb0000000" if PPC_BOOK3S_32 && STRICT_KERNEL_RWX
 	default "0xc0000000"
 endmenu
 

@@ -184,17 +184,7 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
  */
 #define VMALLOC_OFFSET (0x1000000) /* 16M */
 
-/*
- * With CONFIG_STRICT_KERNEL_RWX, kernel segments are set NX. But when modules
- * are used, NX cannot be set on VMALLOC space. So vmalloc VM space and linear
- * memory shall not share segments.
- */
-#if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_MODULES)
-#define VMALLOC_START ((ALIGN((long)high_memory, 256L << 20) + VMALLOC_OFFSET) & \
-		       ~(VMALLOC_OFFSET - 1))
-#else
 #define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
-#endif
 
 #ifdef CONFIG_KASAN_VMALLOC
 #define VMALLOC_END	ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)

@@ -202,6 +192,11 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
 #define VMALLOC_END	ioremap_bot
 #endif
 
+#ifdef CONFIG_STRICT_KERNEL_RWX
+#define MODULES_END	ALIGN_DOWN(PAGE_OFFSET, SZ_256M)
+#define MODULES_VADDR	(MODULES_END - SZ_256M)
+#endif
+
 #ifndef __ASSEMBLY__
 #include <linux/sched.h>
 #include <linux/threads.h>

@@ -74,6 +74,10 @@ struct addr_marker {
 
 static struct addr_marker address_markers[] = {
 	{ 0,	"Start of kernel VM" },
+#ifdef MODULES_VADDR
+	{ 0,	"modules start" },
+	{ 0,	"modules end" },
+#endif
 	{ 0,	"vmalloc() Area" },
 	{ 0,	"vmalloc() End" },
 #ifdef CONFIG_PPC64

@@ -352,6 +356,10 @@ static void populate_markers(void)
 	address_markers[i++].start_address = PAGE_OFFSET;
 #else
 	address_markers[i++].start_address = TASK_SIZE;
+#endif
+#ifdef MODULES_VADDR
+	address_markers[i++].start_address = MODULES_VADDR;
+	address_markers[i++].start_address = MODULES_END;
 #endif
 	address_markers[i++].start_address = VMALLOC_START;
 	address_markers[i++].start_address = VMALLOC_END;

@@ -93,7 +93,7 @@ static int map_patch_area(void *addr, unsigned long text_poke_addr)
 	unsigned long pfn;
 	int err;
 
-	if (is_vmalloc_addr(addr))
+	if (is_vmalloc_or_module_addr(addr))
 		pfn = vmalloc_to_pfn(addr);
 	else
 		pfn = __pa_symbol(addr) >> PAGE_SHIFT;

@@ -474,7 +474,7 @@ InstructionTLBMiss:
 	/* Get PTE (linux-style) and check access */
 	mfspr	r3,SPRN_IMISS
 #if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
-	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
+	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 #endif
 	mfspr	r2, SPRN_SPRG_PGDIR

@@ -484,7 +484,7 @@ InstructionTLBMiss:
 	li	r1,_PAGE_PRESENT | _PAGE_EXEC
 #endif
 #if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
-	bge-	112f
+	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 #endif

@@ -541,7 +541,7 @@ DataLoadTLBMiss:
  */
 	/* Get PTE (linux-style) and check access */
 	mfspr	r3,SPRN_DMISS
-	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
+	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 	mfspr	r2, SPRN_SPRG_PGDIR
 #ifdef CONFIG_SWAP

@@ -549,7 +549,7 @@ DataLoadTLBMiss:
 #else
 	li	r1, _PAGE_PRESENT
 #endif
-	bge-	112f
+	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 112:	rlwimi	r2,r3,12,20,29		/* insert top 10 bits of address */

@@ -621,7 +621,7 @@ DataStoreTLBMiss:
  */
 	/* Get PTE (linux-style) and check access */
 	mfspr	r3,SPRN_DMISS
-	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
+	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 	mfspr	r2, SPRN_SPRG_PGDIR
 #ifdef CONFIG_SWAP

@@ -629,7 +629,7 @@ DataStoreTLBMiss:
 #else
 	li	r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT
 #endif
-	bge-	112f
+	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 112:	rlwimi	r2,r3,12,20,29		/* insert top 10 bits of address */

@@ -62,7 +62,7 @@ _GLOBAL(hash_page)
 	isync
 #endif
 	/* Get PTE (linux-style) and check access */
-	lis	r0,KERNELBASE@h		/* check if kernel address */
+	lis	r0, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r4,r0
 	ori	r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */
 	mfspr	r5, SPRN_SPRG_PGDIR	/* phys page-table root */

@@ -187,6 +187,17 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
 	return __mmu_mapin_ram(border, top);
 }
 
+static bool is_module_segment(unsigned long addr)
+{
+	if (!IS_ENABLED(CONFIG_MODULES))
+		return false;
+	if (addr < ALIGN_DOWN(VMALLOC_START, SZ_256M))
+		return false;
+	if (addr >= ALIGN(VMALLOC_END, SZ_256M))
+		return false;
+	return true;
+}
+
 void mmu_mark_initmem_nx(void)
 {
 	int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;

@@ -223,9 +234,9 @@ void mmu_mark_initmem_nx(void)
 
 	for (i = TASK_SIZE >> 28; i < 16; i++) {
 		/* Do not set NX on VM space for modules */
-		if (IS_ENABLED(CONFIG_MODULES) &&
-		    (VMALLOC_START & 0xf0000000) == i << 28)
-			break;
+		if (is_module_segment(i << 28))
+			continue;
+
 		mtsrin(mfsrin(i << 28) | 0x10000000, i << 28);
 	}
 }