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RISC-V Fixes for 6.4-rc6

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* A fix to avoid ISA-disallowed privilege mappings that can result from
   WRITE+EXEC mmap requests from userspace.
 * A fix for kfence to handle the huge pages.
 * A fix to avoid converting misaligned VAs to huge pages.
 * ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE has been selected so kprobe can
   understand user pointers.
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Merge tag 'riscv-for-linus-6.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - A fix to avoid ISA-disallowed privilege mappings that can result from
   WRITE+EXEC mmap requests from userspace.

 - A fix for kfence to handle the huge pages.

 - A fix to avoid converting misaligned VAs to huge pages.

 - ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE has been selected so kprobe
   can understand user pointers.

* tag 'riscv-for-linus-6.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: fix kprobe __user string arg print fault issue
  riscv: Check the virtual alignment before choosing a map size
  riscv: Fix kfence now that the linear mapping can be backed by PUD/P4D/PGD
  riscv: mm: Ensure prot of VM_WRITE and VM_EXEC must be readable
This commit is contained in:
Linus Torvalds 2023-06-09 09:36:17 -07:00
commit 0f506c7f7d
4 changed files with 39 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/riscv/Kconfig
View File

@ -26,6 +26,7 @@ config RISCV
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
select ARCH_HAS_MMIOWB
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PMEM_API
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SET_DIRECT_MAP if MMU

33
arch/riscv/include/asm/kfence.h
View File

@ -8,41 +8,8 @@
#include <asm-generic/pgalloc.h>
#include <asm/pgtable.h>
static inline int split_pmd_page(unsigned long addr)
{
int i;
unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK)));
pmd_t *pmd = pmd_off_k(addr);
pte_t *pte = pte_alloc_one_kernel(&init_mm);
if (!pte)
return -ENOMEM;
for (i = 0; i < PTRS_PER_PTE; i++)
set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL));
set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(pte)), PAGE_TABLE));
flush_tlb_kernel_range(addr, addr + PMD_SIZE);
return 0;
}
static inline bool arch_kfence_init_pool(void)
{
int ret;
unsigned long addr;
pmd_t *pmd;
for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
addr += PAGE_SIZE) {
pmd = pmd_off_k(addr);
if (pmd_leaf(*pmd)) {
ret = split_pmd_page(addr);
if (ret)
return false;
}
}
return true;
}

3
arch/riscv/include/asm/pgtable.h
View File

@ -165,8 +165,7 @@ extern struct pt_alloc_ops pt_ops __initdata;
_PAGE_EXEC | _PAGE_WRITE)
#define PAGE_COPY PAGE_READ
#define PAGE_COPY_EXEC PAGE_EXEC
#define PAGE_COPY_READ_EXEC PAGE_READ_EXEC
#define PAGE_COPY_EXEC PAGE_READ_EXEC
#define PAGE_SHARED PAGE_WRITE
#define PAGE_SHARED_EXEC PAGE_WRITE_EXEC

48
arch/riscv/mm/init.c
View File

@ -23,6 +23,7 @@
#ifdef CONFIG_RELOCATABLE
#include <linux/elf.h>
#endif
#include <linux/kfence.h>
#include <asm/fixmap.h>
#include <asm/tlbflush.h>
@ -293,7 +294,7 @@ static const pgprot_t protection_map[16] = {
[VM_EXEC] = PAGE_EXEC,
[VM_EXEC | VM_READ] = PAGE_READ_EXEC,
[VM_EXEC | VM_WRITE] = PAGE_COPY_EXEC,
[VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_READ_EXEC,
[VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_EXEC,
[VM_SHARED] = PAGE_NONE,
[VM_SHARED | VM_READ] = PAGE_READ,
[VM_SHARED | VM_WRITE] = PAGE_SHARED,
@ -659,18 +660,19 @@ void __init create_pgd_mapping(pgd_t *pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
static uintptr_t __init best_map_size(phys_addr_t pa, uintptr_t va,
phys_addr_t size)
{
if (!(base & (PGDIR_SIZE - 1)) && size >= PGDIR_SIZE)
if (!(pa & (PGDIR_SIZE - 1)) && !(va & (PGDIR_SIZE - 1)) && size >= PGDIR_SIZE)
return PGDIR_SIZE;
if (!(base & (P4D_SIZE - 1)) && size >= P4D_SIZE)
if (!(pa & (P4D_SIZE - 1)) && !(va & (P4D_SIZE - 1)) && size >= P4D_SIZE)
return P4D_SIZE;
if (!(base & (PUD_SIZE - 1)) && size >= PUD_SIZE)
if (!(pa & (PUD_SIZE - 1)) && !(va & (PUD_SIZE - 1)) && size >= PUD_SIZE)
return PUD_SIZE;
if (!(base & (PMD_SIZE - 1)) && size >= PMD_SIZE)
if (!(pa & (PMD_SIZE - 1)) && !(va & (PMD_SIZE - 1)) && size >= PMD_SIZE)
return PMD_SIZE;
return PAGE_SIZE;
@ -1167,14 +1169,16 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
}
static void __init create_linear_mapping_range(phys_addr_t start,
phys_addr_t end)
phys_addr_t end,
uintptr_t fixed_map_size)
{
phys_addr_t pa;
uintptr_t va, map_size;
for (pa = start; pa < end; pa += map_size) {
va = (uintptr_t)__va(pa);
map_size = best_map_size(pa, end - pa);
map_size = fixed_map_size ? fixed_map_size :
best_map_size(pa, va, end - pa);
create_pgd_mapping(swapper_pg_dir, va, pa, map_size,
pgprot_from_va(va));
@ -1184,6 +1188,7 @@ static void __init create_linear_mapping_range(phys_addr_t start,
static void __init create_linear_mapping_page_table(void)
{
phys_addr_t start, end;
phys_addr_t kfence_pool __maybe_unused;
u64 i;
#ifdef CONFIG_STRICT_KERNEL_RWX
@ -1197,6 +1202,19 @@ static void __init create_linear_mapping_page_table(void)
memblock_mark_nomap(krodata_start, krodata_size);
#endif
#ifdef CONFIG_KFENCE
/*
* kfence pool must be backed by PAGE_SIZE mappings, so allocate it
* before we setup the linear mapping so that we avoid using hugepages
* for this region.
*/
kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
BUG_ON(!kfence_pool);
memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE);
__kfence_pool = __va(kfence_pool);
#endif
/* Map all memory banks in the linear mapping */
for_each_mem_range(i, &start, &end) {
if (start >= end)
@ -1207,17 +1225,25 @@ static void __init create_linear_mapping_page_table(void)
if (end >= __pa(PAGE_OFFSET) + memory_limit)
end = __pa(PAGE_OFFSET) + memory_limit;
create_linear_mapping_range(start, end);
create_linear_mapping_range(start, end, 0);
}
#ifdef CONFIG_STRICT_KERNEL_RWX
create_linear_mapping_range(ktext_start, ktext_start + ktext_size);
create_linear_mapping_range(ktext_start, ktext_start + ktext_size, 0);
create_linear_mapping_range(krodata_start,
krodata_start + krodata_size);
krodata_start + krodata_size, 0);
memblock_clear_nomap(ktext_start, ktext_size);
memblock_clear_nomap(krodata_start, krodata_size);
#endif
#ifdef CONFIG_KFENCE
create_linear_mapping_range(kfence_pool,
kfence_pool + KFENCE_POOL_SIZE,
PAGE_SIZE);
memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE);
#endif
}
static void __init setup_vm_final(void)