| Message ID | 20180601080918.11918-1-yaojun8558363@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/06/18 09:09, Jun Yao wrote: > Migrate swapper_pg_dir and tramp_pg_dir. And their virtual addresses > do not correlate with kernel's address. I think this might break software PAN, which IIRC depends on the reserved TTBR0 PGD being physically adjacent to the live swapper PGD for the trickery in __uaccess_ttbr0_{en,dis}able() to work. Robin. > Signed-off-by: Jun Yao <yaojun8558363@gmail.com> > --- > arch/arm64/mm/mmu.c | 70 +++++++++++++++++++++++++++------------------ > 1 file changed, 42 insertions(+), 28 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 26ba3e70a91c..5baae59479d8 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -57,6 +57,9 @@ EXPORT_SYMBOL(kimage_voffset); > > phys_addr_t __pa_swapper_pg_dir; > pgd_t *new_swapper_pg_dir = swapper_pg_dir; > +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 > +pgd_t *new_tramp_pg_dir; > +#endif > > /* > * Empty_zero_page is a special page that is used for zero-initialized data > @@ -80,19 +83,14 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > } > EXPORT_SYMBOL(phys_mem_access_prot); > > -static phys_addr_t __init early_pgtable_alloc(void) > +static void __init clear_page_phys(phys_addr_t phys) > { > - phys_addr_t phys; > - void *ptr; > - > - phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE); > - > /* > * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE > * slot will be free, so we can (ab)use the FIX_PTE slot to initialise > * any level of table. > */ > - ptr = pte_set_fixmap(phys); > + void *ptr = pte_set_fixmap(phys); > > memset(ptr, 0, PAGE_SIZE); > > @@ -101,6 +99,14 @@ static phys_addr_t __init early_pgtable_alloc(void) > * table walker > */ > pte_clear_fixmap(); > +} > + > +static phys_addr_t __init early_pgtable_alloc(void) > +{ > + phys_addr_t phys; > + > + phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE); > + clear_page_phys(phys); > > return phys; > } > @@ -554,6 +560,10 @@ static int __init map_entry_trampoline(void) > __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, > prot, pgd_pgtable_alloc, 0); > > + memcpy(new_tramp_pg_dir, tramp_pg_dir, PGD_SIZE); > + memblock_free(__pa_symbol(tramp_pg_dir), > + __pa_symbol(swapper_pg_dir) - __pa_symbol(tramp_pg_dir)); > + > /* Map both the text and data into the kernel page table */ > __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { > @@ -631,36 +641,40 @@ static void __init map_kernel(pgd_t *pgdp) > */ > void __init paging_init(void) > { > - phys_addr_t pgd_phys = early_pgtable_alloc(); > - pgd_t *pgdp = pgd_set_fixmap(pgd_phys); > + phys_addr_t pgd_phys; > + pgd_t *pgdp; > + > +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 > + phys_addr_t mem_size; > + phys_addr_t p; > > - __pa_swapper_pg_dir = __pa_symbol(swapper_pg_dir); > + mem_size = __pa_symbol(swapper_pg_dir) + PAGE_SIZE > + - __pa_symbol(tramp_pg_dir); > + pgd_phys = memblock_alloc(mem_size, PAGE_SIZE); > + > + for (p = pgd_phys; p < pgd_phys + mem_size; p += PAGE_SIZE) > + clear_page_phys(p); > + > + new_tramp_pg_dir = __va(pgd_phys); > + __pa_swapper_pg_dir = pgd_phys + PAGE_SIZE; > +#else > + pgd_phys = early_pgtable_alloc(); > + __pa_swapper_pg_dir = pgd_phys; > +#endif > + new_swapper_pg_dir = __va(__pa_swapper_pg_dir); > + > + pgdp = pgd_set_fixmap(__pa_swapper_pg_dir); > > map_kernel(pgdp); > map_mem(pgdp); > > - /* > - * We want to reuse the original swapper_pg_dir so we don't have to > - * communicate the new address to non-coherent secondaries in > - * secondary_entry, and so cpu_switch_mm can generate the address with > - * adrp+add rather than a load from some global variable. > - * > - * To do this we need to go via a temporary pgd. > - */ > - cpu_replace_ttbr1(pgd_phys); > - memcpy(swapper_pg_dir, pgdp, PGD_SIZE); > cpu_replace_ttbr1(__pa_swapper_pg_dir); > + init_mm.pgd = new_swapper_pg_dir; > > pgd_clear_fixmap(); > - memblock_free(pgd_phys, PAGE_SIZE); > > - /* > - * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd > - * allocated with it. > - */ > - memblock_free(__pa_symbol(swapper_pg_dir) + PAGE_SIZE, > - __pa_symbol(swapper_pg_end) - __pa_symbol(swapper_pg_dir) > - - PAGE_SIZE); > + memblock_free(__pa_symbol(swapper_pg_dir), > + __pa_symbol(swapper_pg_end) - __pa_symbol(swapper_pg_dir)); > } > > /* >
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 26ba3e70a91c..5baae59479d8 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -57,6 +57,9 @@ EXPORT_SYMBOL(kimage_voffset); phys_addr_t __pa_swapper_pg_dir; pgd_t *new_swapper_pg_dir = swapper_pg_dir; +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +pgd_t *new_tramp_pg_dir; +#endif /* * Empty_zero_page is a special page that is used for zero-initialized data @@ -80,19 +83,14 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, } EXPORT_SYMBOL(phys_mem_access_prot); -static phys_addr_t __init early_pgtable_alloc(void) +static void __init clear_page_phys(phys_addr_t phys) { - phys_addr_t phys; - void *ptr; - - phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE); - /* * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE * slot will be free, so we can (ab)use the FIX_PTE slot to initialise * any level of table. */ - ptr = pte_set_fixmap(phys); + void *ptr = pte_set_fixmap(phys); memset(ptr, 0, PAGE_SIZE); @@ -101,6 +99,14 @@ static phys_addr_t __init early_pgtable_alloc(void) * table walker */ pte_clear_fixmap(); +} + +static phys_addr_t __init early_pgtable_alloc(void) +{ + phys_addr_t phys; + + phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE); + clear_page_phys(phys); return phys; } @@ -554,6 +560,10 @@ static int __init map_entry_trampoline(void) __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, prot, pgd_pgtable_alloc, 0); + memcpy(new_tramp_pg_dir, tramp_pg_dir, PGD_SIZE); + memblock_free(__pa_symbol(tramp_pg_dir), + __pa_symbol(swapper_pg_dir) - __pa_symbol(tramp_pg_dir)); + /* Map both the text and data into the kernel page table */ __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { @@ -631,36 +641,40 @@ static void __init map_kernel(pgd_t *pgdp) */ void __init paging_init(void) { - phys_addr_t pgd_phys = early_pgtable_alloc(); - pgd_t *pgdp = pgd_set_fixmap(pgd_phys); + phys_addr_t pgd_phys; + pgd_t *pgdp; + +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 + phys_addr_t mem_size; + phys_addr_t p; - __pa_swapper_pg_dir = __pa_symbol(swapper_pg_dir); + mem_size = __pa_symbol(swapper_pg_dir) + PAGE_SIZE + - __pa_symbol(tramp_pg_dir); + pgd_phys = memblock_alloc(mem_size, PAGE_SIZE); + + for (p = pgd_phys; p < pgd_phys + mem_size; p += PAGE_SIZE) + clear_page_phys(p); + + new_tramp_pg_dir = __va(pgd_phys); + __pa_swapper_pg_dir = pgd_phys + PAGE_SIZE; +#else + pgd_phys = early_pgtable_alloc(); + __pa_swapper_pg_dir = pgd_phys; +#endif + new_swapper_pg_dir = __va(__pa_swapper_pg_dir); + + pgdp = pgd_set_fixmap(__pa_swapper_pg_dir); map_kernel(pgdp); map_mem(pgdp); - /* - * We want to reuse the original swapper_pg_dir so we don't have to - * communicate the new address to non-coherent secondaries in - * secondary_entry, and so cpu_switch_mm can generate the address with - * adrp+add rather than a load from some global variable. - * - * To do this we need to go via a temporary pgd. - */ - cpu_replace_ttbr1(pgd_phys); - memcpy(swapper_pg_dir, pgdp, PGD_SIZE); cpu_replace_ttbr1(__pa_swapper_pg_dir); + init_mm.pgd = new_swapper_pg_dir; pgd_clear_fixmap(); - memblock_free(pgd_phys, PAGE_SIZE); - /* - * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd - * allocated with it. - */ - memblock_free(__pa_symbol(swapper_pg_dir) + PAGE_SIZE, - __pa_symbol(swapper_pg_end) - __pa_symbol(swapper_pg_dir) - - PAGE_SIZE); + memblock_free(__pa_symbol(swapper_pg_dir), + __pa_symbol(swapper_pg_end) - __pa_symbol(swapper_pg_dir)); } /*
Migrate swapper_pg_dir and tramp_pg_dir. And their virtual addresses do not correlate with kernel's address. Signed-off-by: Jun Yao <yaojun8558363@gmail.com> --- arch/arm64/mm/mmu.c | 70 +++++++++++++++++++++++++++------------------ 1 file changed, 42 insertions(+), 28 deletions(-)