For UEFI, we need to install the memory mappings used for Runtime Services
in a dedicated set of page tables. Add create_pgd_mapping(), which allows
us to allocate and install those page table entries early.
This also adds a 'map_xn' option, that creates regions with the PXN and
UXN bits set.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/include/asm/mmu.h | 3 +++
arch/arm64/mm/mmu.c | 28 ++++++++++++++++++++--------
2 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index c2f006c48bdb..bcf166043a8b 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -33,5 +33,8 @@ extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
extern void init_mem_pgprot(void);
/* create an identity mapping for memory (or io if map_io is true) */
extern void create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io);
+extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
+ unsigned long virt, phys_addr_t size,
+ int map_io, int map_xn);
#endif
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 7eaa6a8c8467..f7d17a5a1f56 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -157,7 +157,7 @@ static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
static void __init alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
unsigned long addr, unsigned long end,
- phys_addr_t phys, int map_io)
+ phys_addr_t phys, int map_io, int map_xn)
{
pmd_t *pmd;
unsigned long next;
@@ -167,6 +167,9 @@ static void __init alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
if (map_io) {
prot_sect = PROT_SECT_DEVICE_nGnRE;
prot_pte = __pgprot(PROT_DEVICE_nGnRE);
+ } else if (map_xn) {
+ prot_sect = PROT_SECT_NORMAL;
+ prot_pte = PAGE_KERNEL;
} else {
prot_sect = PROT_SECT_NORMAL_EXEC;
prot_pte = PAGE_KERNEL_EXEC;
@@ -203,7 +206,7 @@ static void __init alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
unsigned long addr, unsigned long end,
- unsigned long phys, int map_io)
+ unsigned long phys, int map_io, int map_xn)
{
pud_t *pud;
unsigned long next;
@@ -221,7 +224,7 @@ static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
/*
* For 4K granule only, attempt to put down a 1GB block
*/
- if (!map_io && (PAGE_SHIFT == 12) &&
+ if (!map_io && !map_xn && (PAGE_SHIFT == 12) &&
((addr | next | phys) & ~PUD_MASK) == 0) {
pud_t old_pud = *pud;
set_pud(pud, __pud(phys | PROT_SECT_NORMAL_EXEC));
@@ -239,7 +242,8 @@ static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
flush_tlb_all();
}
} else {
- alloc_init_pmd(mm, pud, addr, next, phys, map_io);
+ alloc_init_pmd(mm, pud, addr, next, phys, map_io,
+ map_xn);
}
phys += next - addr;
} while (pud++, addr = next, addr != end);
@@ -251,7 +255,7 @@ static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
*/
static void __init __create_mapping(struct mm_struct *mm, pgd_t *pgd,
phys_addr_t phys, unsigned long virt,
- phys_addr_t size, int map_io)
+ phys_addr_t size, int map_io, int map_xn)
{
unsigned long addr, length, end, next;
@@ -261,7 +265,7 @@ static void __init __create_mapping(struct mm_struct *mm, pgd_t *pgd,
end = addr + length;
do {
next = pgd_addr_end(addr, end);
- alloc_init_pud(mm, pgd, addr, next, phys, map_io);
+ alloc_init_pud(mm, pgd, addr, next, phys, map_io, map_xn);
phys += next - addr;
} while (pgd++, addr = next, addr != end);
}
@@ -275,7 +279,7 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt,
return;
}
__create_mapping(&init_mm, pgd_offset_k(virt & PAGE_MASK), phys, virt,
- size, 0);
+ size, 0, 0);
}
void __init create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io)
@@ -285,7 +289,15 @@ void __init create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io)
return;
}
__create_mapping(&init_mm, &idmap_pg_dir[pgd_index(addr)],
- addr, addr, size, map_io);
+ addr, addr, size, map_io, 0);
+}
+
+void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
+ unsigned long virt, phys_addr_t size,
+ int map_io, int map_xn)
+{
+ __create_mapping(mm, pgd_offset(mm, virt), phys, virt, size, map_io,
+ map_xn);
}
static void __init map_mem(void)
--
1.8.3.2
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