X-Git-Url: https://repo.jachan.dev/J-linux.git/blobdiff_plain/c28c15b6d28a776538482101522cbcd9f906b15c..901b894af5b933cf6576eec05746f34b46e2ac83:/arch/powerpc/lib/code-patching.c

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index a1902241ff5d..b00112d7ad46 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -46,12 +46,16 @@ int raw_patch_instruction(u32 *addr, ppc_inst_t instr)
 	return __patch_instruction(addr, instr, addr);
 }
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
+struct patch_context {
+	union {
+		struct vm_struct *area;
+		struct mm_struct *mm;
+	};
+	unsigned long addr;
+	pte_t *pte;
+};
 
-static DEFINE_PER_CPU(struct vm_struct *, text_poke_area);
-static DEFINE_PER_CPU(struct mm_struct *, cpu_patching_mm);
-static DEFINE_PER_CPU(unsigned long, cpu_patching_addr);
-static DEFINE_PER_CPU(pte_t *, cpu_patching_pte);
+static DEFINE_PER_CPU(struct patch_context, cpu_patching_context);
 
 static int map_patch_area(void *addr, unsigned long text_poke_addr);
 static void unmap_patch_area(unsigned long addr);
@@ -116,14 +120,19 @@ static int text_area_cpu_up(unsigned int cpu)
 
 	unmap_patch_area(addr);
 
-	this_cpu_write(text_poke_area, area);
+	this_cpu_write(cpu_patching_context.area, area);
+	this_cpu_write(cpu_patching_context.addr, addr);
+	this_cpu_write(cpu_patching_context.pte, virt_to_kpte(addr));
 
 	return 0;
 }
 
 static int text_area_cpu_down(unsigned int cpu)
 {
-	free_vm_area(this_cpu_read(text_poke_area));
+	free_vm_area(this_cpu_read(cpu_patching_context.area));
+	this_cpu_write(cpu_patching_context.area, NULL);
+	this_cpu_write(cpu_patching_context.addr, 0);
+	this_cpu_write(cpu_patching_context.pte, NULL);
 	return 0;
 }
 
@@ -167,9 +176,8 @@ static int text_area_cpu_up_mm(unsigned int cpu)
 		goto fail_no_pte;
 	pte_unmap_unlock(pte, ptl);
 
-	this_cpu_write(cpu_patching_mm, mm);
-	this_cpu_write(cpu_patching_addr, addr);
-	this_cpu_write(cpu_patching_pte, pte);
+	this_cpu_write(cpu_patching_context.mm, mm);
+	this_cpu_write(cpu_patching_context.addr, addr);
 
 	return 0;
 
@@ -181,12 +189,11 @@ fail_no_mm:
 
 static int text_area_cpu_down_mm(unsigned int cpu)
 {
-	put_patching_mm(this_cpu_read(cpu_patching_mm),
-			this_cpu_read(cpu_patching_addr));
+	put_patching_mm(this_cpu_read(cpu_patching_context.mm),
+			this_cpu_read(cpu_patching_context.addr));
 
-	this_cpu_write(cpu_patching_mm, NULL);
-	this_cpu_write(cpu_patching_addr, 0);
-	this_cpu_write(cpu_patching_pte, NULL);
+	this_cpu_write(cpu_patching_context.mm, NULL);
+	this_cpu_write(cpu_patching_context.addr, 0);
 
 	return 0;
 }
@@ -197,6 +204,9 @@ void __init poking_init(void)
 {
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
+		return;
+
 	if (mm_patch_enabled())
 		ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
 					"powerpc/text_poke_mm:online",
@@ -277,12 +287,16 @@ static int __do_patch_instruction_mm(u32 *addr, ppc_inst_t instr)
 	unsigned long pfn = get_patch_pfn(addr);
 	struct mm_struct *patching_mm;
 	struct mm_struct *orig_mm;
+	spinlock_t *ptl;
 
-	patching_mm = __this_cpu_read(cpu_patching_mm);
-	pte = __this_cpu_read(cpu_patching_pte);
-	text_poke_addr = __this_cpu_read(cpu_patching_addr);
+	patching_mm = __this_cpu_read(cpu_patching_context.mm);
+	text_poke_addr = __this_cpu_read(cpu_patching_context.addr);
 	patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr));
 
+	pte = get_locked_pte(patching_mm, text_poke_addr, &ptl);
+	if (!pte)
+		return -ENOMEM;
+
 	__set_pte_at(patching_mm, text_poke_addr, pte, pfn_pte(pfn, PAGE_KERNEL), 0);
 
 	/* order PTE update before use, also serves as the hwsync */
@@ -309,6 +323,8 @@ static int __do_patch_instruction_mm(u32 *addr, ppc_inst_t instr)
 	 */
 	local_flush_tlb_page_psize(patching_mm, text_poke_addr, mmu_virtual_psize);
 
+	pte_unmap_unlock(pte, ptl);
+
 	return err;
 }
 
@@ -320,10 +336,10 @@ static int __do_patch_instruction(u32 *addr, ppc_inst_t instr)
 	pte_t *pte;
 	unsigned long pfn = get_patch_pfn(addr);
 
-	text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr & PAGE_MASK;
+	text_poke_addr = (unsigned long)__this_cpu_read(cpu_patching_context.addr) & PAGE_MASK;
 	patch_addr = (u32 *)(text_poke_addr + offset_in_page(addr));
 
-	pte = virt_to_kpte(text_poke_addr);
+	pte = __this_cpu_read(cpu_patching_context.pte);
 	__set_pte_at(&init_mm, text_poke_addr, pte, pfn_pte(pfn, PAGE_KERNEL), 0);
 	/* See ptesync comment in radix__set_pte_at() */
 	if (radix_enabled())
@@ -337,7 +353,7 @@ static int __do_patch_instruction(u32 *addr, ppc_inst_t instr)
 	return err;
 }
 
-static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
+int patch_instruction(u32 *addr, ppc_inst_t instr)
 {
 	int err;
 	unsigned long flags;
@@ -347,7 +363,8 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
 	 * when text_poke_area is not ready, but we still need
 	 * to allow patching. We just do the plain old patching
 	 */
-	if (!static_branch_likely(&poking_init_done))
+	if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) ||
+	    !static_branch_likely(&poking_init_done))
 		return raw_patch_instruction(addr, instr);
 
 	local_irq_save(flags);
@@ -359,25 +376,6 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
 
 	return err;
 }
-#else /* !CONFIG_STRICT_KERNEL_RWX */
-
-static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
-{
-	return raw_patch_instruction(addr, instr);
-}
-
-#endif /* CONFIG_STRICT_KERNEL_RWX */
-
-__ro_after_init DEFINE_STATIC_KEY_FALSE(init_mem_is_free);
-
-int patch_instruction(u32 *addr, ppc_inst_t instr)
-{
-	/* Make sure we aren't patching a freed init section */
-	if (static_branch_likely(&init_mem_is_free) && init_section_contains(addr, 4))
-		return 0;
-
-	return do_patch_instruction(addr, instr);
-}
 NOKPROBE_SYMBOL(patch_instruction);
 
 int patch_branch(u32 *addr, unsigned long target, int flags)