[PATCH v10 17/22] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct

[Steven Price]

To enable x86 to use the generic walk_page_range() function, the
callers of ptdump_walk_pgd_level_debugfs() need to pass in the mm_struct.

This means that ptdump_walk_pgd_level_core() is now always passed a
valid pgd, so drop the support for pgd==NULL.

Signed-off-by: Steven Price <steven.pr...@arm.com>
---
 arch/x86/include/asm/pgtable.h |  3 ++-
 arch/x86/mm/debug_pagetables.c |  8 ++++----
 arch/x86/mm/dump_pagetables.c  | 14 ++++++--------
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1a2b469f6e75..1b255987712e 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -30,7 +30,8 @@ extern pgd_t early_top_pgt[PTRS_PER_PGD];
 int __init __early_make_pgtable(unsigned long address, pmdval_t pmd);
 
 void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm);
-void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user);
+void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
+                                  bool user);
 void ptdump_walk_pgd_level_checkwx(void);
 void ptdump_walk_user_pgd_level_checkwx(void);
 
diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
index 39001a401eff..d0efec713c6c 100644
--- a/arch/x86/mm/debug_pagetables.c
+++ b/arch/x86/mm/debug_pagetables.c
@@ -7,7 +7,7 @@
 
 static int ptdump_show(struct seq_file *m, void *v)
 {
-       ptdump_walk_pgd_level_debugfs(m, NULL, false);
+       ptdump_walk_pgd_level_debugfs(m, &init_mm, false);
        return 0;
 }
 
@@ -17,7 +17,7 @@ static int ptdump_curknl_show(struct seq_file *m, void *v)
 {
        if (current->mm->pgd) {
                down_read(&current->mm->mmap_sem);
-               ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
+               ptdump_walk_pgd_level_debugfs(m, current->mm, false);
                up_read(&current->mm->mmap_sem);
        }
        return 0;
@@ -30,7 +30,7 @@ static int ptdump_curusr_show(struct seq_file *m, void *v)
 {
        if (current->mm->pgd) {
                down_read(&current->mm->mmap_sem);
-               ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
+               ptdump_walk_pgd_level_debugfs(m, current->mm, true);
                up_read(&current->mm->mmap_sem);
        }
        return 0;
@@ -43,7 +43,7 @@ DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);
 static int ptdump_efi_show(struct seq_file *m, void *v)
 {
        if (efi_mm.pgd)
-               ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false);
+               ptdump_walk_pgd_level_debugfs(m, &efi_mm, false);
        return 0;
 }
 
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 24fe76325b31..2f5f32f21f81 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -518,16 +518,12 @@ static inline bool is_hypervisor_range(int idx)
 static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
                                       bool checkwx, bool dmesg)
 {
-       pgd_t *start = INIT_PGD;
+       pgd_t *start = pgd;
        pgprotval_t prot, eff;
        int i;
        struct pg_state st = {};
 
-       if (pgd) {
-               start = pgd;
-               st.to_dmesg = dmesg;
-       }
-
+       st.to_dmesg = dmesg;
        st.check_wx = checkwx;
        st.seq = m;
        if (checkwx)
@@ -572,8 +568,10 @@ void ptdump_walk_pgd_level(struct seq_file *m, struct 
mm_struct *mm)
        ptdump_walk_pgd_level_core(m, mm->pgd, false, true);
 }
 
-void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user)
+void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
+                                  bool user)
 {
+       pgd_t *pgd = mm->pgd;
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
        if (user && boot_cpu_has(X86_FEATURE_PTI))
                pgd = kernel_to_user_pgdp(pgd);
@@ -599,7 +597,7 @@ void ptdump_walk_user_pgd_level_checkwx(void)
 
 void ptdump_walk_pgd_level_checkwx(void)
 {
-       ptdump_walk_pgd_level_core(NULL, NULL, true, false);
+       ptdump_walk_pgd_level_core(NULL, INIT_PGD, true, false);
 }
 
 static int __init pt_dump_init(void)
-- 
2.20.1