mm: ptdump: have ptdump_check_wx() return bool

Have ptdump_check_wx() return true when the check is successful or false
otherwise.

[akpm@linux-foundation.org: fix a couple of build issues (x86_64 allmodconfig)]
Link: https://lkml.kernel.org/r/7943149fe955458cb7b57cd483bf41a3aad94684.1706610398.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Phong Tran <tranmanphong@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Price <steven.price@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm64/mm/ptdump.c

@@ -345,7 +345,7 @@ static struct ptdump_info kernel_ptdump_info = {
 	.base_addr	= PAGE_OFFSET,
 };
 
-void ptdump_check_wx(void)
+bool ptdump_check_wx(void)
 {
 	struct pg_state st = {
 		.seq = NULL,
@@ -366,11 +366,16 @@ void ptdump_check_wx(void)
 
 	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
 
-	if (st.wx_pages || st.uxn_pages)
+	if (st.wx_pages || st.uxn_pages) {
 		pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n",
 			st.wx_pages, st.uxn_pages);
-	else
+
+		return false;
+	} else {
 		pr_info("Checked W+X mappings: passed, no W+X pages found\n");
+
+		return true;
+	}
 }
 
 static int __init ptdump_init(void)

arch/powerpc/mm/ptdump/ptdump.c

@@ -327,7 +327,7 @@ static void __init build_pgtable_complete_mask(void)
 				pg_level[i].mask |= pg_level[i].flag[j].mask;
 }
 
-void ptdump_check_wx(void)
+bool ptdump_check_wx(void)
 {
 	struct pg_state st = {
 		.seq = NULL,
@@ -344,15 +344,20 @@ void ptdump_check_wx(void)
 	};
 
 	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !mmu_has_feature(MMU_FTR_KERNEL_RO))
-		return;
+		return true;
 
 	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
 
-	if (st.wx_pages)
+	if (st.wx_pages) {
 		pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found\n",
 			st.wx_pages);
-	else
+
+		return false;
+	} else {
 		pr_info("Checked W+X mappings: passed, no W+X pages found\n");
+
+		return true;
+	}
 }
 
 static int __init ptdump_init(void)

arch/riscv/mm/ptdump.c

@@ -335,7 +335,7 @@ static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo)
 	ptdump_walk_pgd(&st.ptdump, pinfo->mm, NULL);
 }
 
-void ptdump_check_wx(void)
+bool ptdump_check_wx(void)
 {
 	struct pg_state st = {
 		.seq = NULL,
@@ -356,11 +356,16 @@ void ptdump_check_wx(void)
 
 	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
 
-	if (st.wx_pages)
+	if (st.wx_pages) {
 		pr_warn("Checked W+X mappings: failed, %lu W+X pages found\n",
 			st.wx_pages);
-	else
+
+		return false;
+	} else {
 		pr_info("Checked W+X mappings: passed, no W+X pages found\n");
+
+		return true;
+	}
 }
 
 static int ptdump_show(struct seq_file *m, void *v)

arch/s390/mm/dump_pagetables.c

@@ -192,7 +192,7 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
 	}
 }
 
-void ptdump_check_wx(void)
+bool ptdump_check_wx(void)
 {
 	struct pg_state st = {
 		.ptdump = {
@@ -215,14 +215,19 @@ void ptdump_check_wx(void)
 	};
 
 	if (!MACHINE_HAS_NX)
-		return;
+		return true;
 	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
-	if (st.wx_pages)
+	if (st.wx_pages) {
 		pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found\n", st.wx_pages);
-	else
+
+		return false;
+	} else {
 		pr_info("Checked W+X mappings: passed, no %sW+X pages found\n",
 			(nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear)) ?
 			"unexpected " : "");
+
+		return true;
+	}
 }
 
 #ifdef CONFIG_PTDUMP_DEBUGFS

arch/x86/include/asm/pgtable.h

@@ -31,7 +31,7 @@ struct seq_file;
 void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm);
 void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
 				   bool user);
-void ptdump_walk_pgd_level_checkwx(void);
+bool ptdump_walk_pgd_level_checkwx(void);
 #define ptdump_check_wx ptdump_walk_pgd_level_checkwx
 void ptdump_walk_user_pgd_level_checkwx(void);
 

arch/x86/mm/dump_pagetables.c

@@ -362,9 +362,9 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
 	}
 }
 
-static void ptdump_walk_pgd_level_core(struct seq_file *m,
-				       struct mm_struct *mm, pgd_t *pgd,
-				       bool checkwx, bool dmesg)
+bool ptdump_walk_pgd_level_core(struct seq_file *m,
+				struct mm_struct *mm, pgd_t *pgd,
+				bool checkwx, bool dmesg)
 {
 	const struct ptdump_range ptdump_ranges[] = {
 #ifdef CONFIG_X86_64
@@ -391,12 +391,17 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m,
 	ptdump_walk_pgd(&st.ptdump, mm, pgd);
 
 	if (!checkwx)
-		return;
-	if (st.wx_pages)
+		return true;
+	if (st.wx_pages) {
 		pr_info("x86/mm: Checked W+X mappings: FAILED, %lu W+X pages found.\n",
 			st.wx_pages);
-	else
+
+		return false;
+	} else {
 		pr_info("x86/mm: Checked W+X mappings: passed, no W+X pages found.\n");
+
+		return true;
+	}
 }
 
 void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm)
@@ -431,12 +436,12 @@ void ptdump_walk_user_pgd_level_checkwx(void)
 #endif
 }
 
-void ptdump_walk_pgd_level_checkwx(void)
+bool ptdump_walk_pgd_level_checkwx(void)
 {
 	if (!(__supported_pte_mask & _PAGE_NX))
-		return;
+		return true;
 
-	ptdump_walk_pgd_level_core(NULL, &init_mm, INIT_PGD, true, false);
+	return ptdump_walk_pgd_level_core(NULL, &init_mm, INIT_PGD, true, false);
 }
 
 static int __init pt_dump_init(void)

include/linux/ptdump.h

@@ -18,8 +18,11 @@ struct ptdump_state {
 	const struct ptdump_range *range;
 };
 
+bool ptdump_walk_pgd_level_core(struct seq_file *m,
+				struct mm_struct *mm, pgd_t *pgd,
+				bool checkwx, bool dmesg);
 void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd);
-void ptdump_check_wx(void);
+bool ptdump_check_wx(void);
 
 static inline void debug_checkwx(void)
 {