From: "David Hildenbrand (Arm)" <[email protected]> pXdp_get() could return a dummy value for a page-table level folded at compile time. Passing this value to set_pXd() could cause unexpected behavior.
Prevent this at compile time by ensuring that all calls to set_pgd()/set_p4d()/set_pud() are compiled out for folded page-table levels. Make the compiler complain if these helpers are called with dummy values. Since there are places where set_pXd() is called even when the corresponding page-table level is folded at compile time, drop the incorrect comments for set_pXd(). Signed-off-by: David Hildenbrand (Arm) <[email protected]> Co-developed-by: Yeoreum Yun <[email protected]> Signed-off-by: Yeoreum Yun <[email protected]> --- include/asm-generic/pgtable-nop4d.h | 11 ++++++----- include/asm-generic/pgtable-nopmd.h | 10 +++++----- include/asm-generic/pgtable-nopud.h | 12 +++++++----- 3 files changed, 18 insertions(+), 15 deletions(-) diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h index d2dccf7542da..12b01768134b 100644 --- a/include/asm-generic/pgtable-nop4d.h +++ b/include/asm-generic/pgtable-nop4d.h @@ -28,11 +28,12 @@ static inline bool pgd_leaf(pgd_t pgd) { return false; } #define pgd_populate(mm, pgd, p4d) do { } while (0) #define pgd_populate_safe(mm, pgd, p4d) do { } while (0) -/* - * (p4ds are folded into pgds so this doesn't get actually called, - * but the define is needed for a generic inline function.) - */ -#define set_pgd(pgdptr, pgdval) set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval }) + +#define set_pgd(pgdptr, pgdval) \ +({ \ + pgd_check_dummy(pgdval); \ + set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval }); \ +}) static __always_inline pgd_t pgdp_get(pgd_t *pgdp) { diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h index 2afbf2d8659d..11b04c107129 100644 --- a/include/asm-generic/pgtable-nopmd.h +++ b/include/asm-generic/pgtable-nopmd.h @@ -37,11 +37,11 @@ static inline void pud_clear(pud_t *pud) { } #define pud_populate(mm, pmd, pte) do { } while (0) -/* - * (pmds are folded into puds so this doesn't get actually called, - * but the define is needed for a generic inline function.) - */ -#define set_pud(pudptr, pudval) set_pmd((pmd_t *)(pudptr), (pmd_t) { pudval }) +#define set_pud(pudptr, pudval) \ +({ \ + pud_check_dummy(pudval); \ + set_pmd((pmd_t *)(pudptr), (pmd_t) { pudval }); \ +}) static __always_inline pud_t pudp_get(pud_t *pudp) { diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h index 3264673c0c38..5ee8f1852cd8 100644 --- a/include/asm-generic/pgtable-nopud.h +++ b/include/asm-generic/pgtable-nopud.h @@ -35,11 +35,13 @@ static inline bool p4d_leaf(p4d_t p4d) { return false; } #define p4d_populate(mm, p4d, pud) do { } while (0) #define p4d_populate_safe(mm, p4d, pud) do { } while (0) -/* - * (puds are folded into p4ds so this doesn't get actually called, - * but the define is needed for a generic inline function.) - */ -#define set_p4d(p4dptr, p4dval) set_pud((pud_t *)(p4dptr), (pud_t) { p4dval }) + +#define set_p4d(p4dptr, p4dval) \ +({ \ + p4d_check_dummy(p4dval); \ + set_pud((pud_t *)(p4dptr), (pud_t) { p4dval }); \ +}) + static __always_inline p4d_t p4dp_get(p4d_t *p4dp) { -- 2.43.0
