| Message ID | 20240814124613.2632226-3-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | x86: Reduce code duplication on page table initialization | expand |
On 8/14/24 07:46, Kirill A. Shutemov wrote: > The function init_transition_pgtable() maps the page with > asm_acpi_mp_play_dead() into an identity mapping. > > Replace manual page table initialization with kernel_ident_mapping_init() > to avoid code duplication. Use x86_mapping_info::offset to get the page > mapped at the correct location. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Reviewed-by: Kai Huang <kai.huang@intel.com> A bit confusing on the last change. You have to understand how kernel_ident_mapping_init() works in regards to supplying an offset value and how to set that offset value up properly to get the kernel VA address into the identity map. Otherwise: Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> > --- > arch/x86/kernel/acpi/madt_wakeup.c | 73 ++++++------------------------ > 1 file changed, 15 insertions(+), 58 deletions(-) > > diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c > index d5ef6215583b..78960b338be9 100644 > --- a/arch/x86/kernel/acpi/madt_wakeup.c > +++ b/arch/x86/kernel/acpi/madt_wakeup.c > @@ -70,58 +70,6 @@ static void __init free_pgt_page(void *pgt, void *dummy) > return memblock_free(pgt, PAGE_SIZE); > } > > -/* > - * Make sure asm_acpi_mp_play_dead() is present in the identity mapping at > - * the same place as in the kernel page tables. asm_acpi_mp_play_dead() switches > - * to the identity mapping and the function has be present at the same spot in > - * the virtual address space before and after switching page tables. > - */ > -static int __init init_transition_pgtable(pgd_t *pgd) > -{ > - pgprot_t prot = PAGE_KERNEL_EXEC_NOENC; > - unsigned long vaddr, paddr; > - p4d_t *p4d; > - pud_t *pud; > - pmd_t *pmd; > - pte_t *pte; > - > - vaddr = (unsigned long)asm_acpi_mp_play_dead; > - pgd += pgd_index(vaddr); > - if (!pgd_present(*pgd)) { > - p4d = (p4d_t *)alloc_pgt_page(NULL); > - if (!p4d) > - return -ENOMEM; > - set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE)); > - } > - p4d = p4d_offset(pgd, vaddr); > - if (!p4d_present(*p4d)) { > - pud = (pud_t *)alloc_pgt_page(NULL); > - if (!pud) > - return -ENOMEM; > - set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE)); > - } > - pud = pud_offset(p4d, vaddr); > - if (!pud_present(*pud)) { > - pmd = (pmd_t *)alloc_pgt_page(NULL); > - if (!pmd) > - return -ENOMEM; > - set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); > - } > - pmd = pmd_offset(pud, vaddr); > - if (!pmd_present(*pmd)) { > - pte = (pte_t *)alloc_pgt_page(NULL); > - if (!pte) > - return -ENOMEM; > - set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); > - } > - pte = pte_offset_kernel(pmd, vaddr); > - > - paddr = __pa(vaddr); > - set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot)); > - > - return 0; > -} > - > static int __init acpi_mp_setup_reset(u64 reset_vector) > { > struct x86_mapping_info info = { > @@ -130,6 +78,7 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) > .page_flag = __PAGE_KERNEL_LARGE_EXEC, > .kernpg_flag = _KERNPG_TABLE_NOENC, > }; > + unsigned long mstart, mend; > pgd_t *pgd; > > pgd = alloc_pgt_page(NULL); > @@ -137,8 +86,6 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) > return -ENOMEM; > > for (int i = 0; i < nr_pfn_mapped; i++) { > - unsigned long mstart, mend; > - > mstart = pfn_mapped[i].start << PAGE_SHIFT; > mend = pfn_mapped[i].end << PAGE_SHIFT; > if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) { > @@ -147,14 +94,24 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) > } > } > > - if (kernel_ident_mapping_init(&info, pgd, > - PAGE_ALIGN_DOWN(reset_vector), > - PAGE_ALIGN(reset_vector + 1))) { > + mstart = PAGE_ALIGN_DOWN(reset_vector); > + mend = mstart + PAGE_SIZE; > + if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) { > kernel_ident_mapping_free(&info, pgd); > return -ENOMEM; > } > > - if (init_transition_pgtable(pgd)) { > + /* > + * Make sure asm_acpi_mp_play_dead() is present in the identity mapping > + * at the same place as in the kernel page tables. > + * asm_acpi_mp_play_dead() switches to the identity mapping and the > + * function has be present at the same spot in the virtual address space > + * before and after switching page tables. > + */ > + info.offset = __START_KERNEL_map - phys_base; > + mstart = PAGE_ALIGN_DOWN(__pa(asm_acpi_mp_play_dead)); > + mend = mstart + PAGE_SIZE; > + if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) { > kernel_ident_mapping_free(&info, pgd); > return -ENOMEM; > }
diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c index d5ef6215583b..78960b338be9 100644 --- a/arch/x86/kernel/acpi/madt_wakeup.c +++ b/arch/x86/kernel/acpi/madt_wakeup.c @@ -70,58 +70,6 @@ static void __init free_pgt_page(void *pgt, void *dummy) return memblock_free(pgt, PAGE_SIZE); } -/* - * Make sure asm_acpi_mp_play_dead() is present in the identity mapping at - * the same place as in the kernel page tables. asm_acpi_mp_play_dead() switches - * to the identity mapping and the function has be present at the same spot in - * the virtual address space before and after switching page tables. - */ -static int __init init_transition_pgtable(pgd_t *pgd) -{ - pgprot_t prot = PAGE_KERNEL_EXEC_NOENC; - unsigned long vaddr, paddr; - p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - - vaddr = (unsigned long)asm_acpi_mp_play_dead; - pgd += pgd_index(vaddr); - if (!pgd_present(*pgd)) { - p4d = (p4d_t *)alloc_pgt_page(NULL); - if (!p4d) - return -ENOMEM; - set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE)); - } - p4d = p4d_offset(pgd, vaddr); - if (!p4d_present(*p4d)) { - pud = (pud_t *)alloc_pgt_page(NULL); - if (!pud) - return -ENOMEM; - set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE)); - } - pud = pud_offset(p4d, vaddr); - if (!pud_present(*pud)) { - pmd = (pmd_t *)alloc_pgt_page(NULL); - if (!pmd) - return -ENOMEM; - set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); - } - pmd = pmd_offset(pud, vaddr); - if (!pmd_present(*pmd)) { - pte = (pte_t *)alloc_pgt_page(NULL); - if (!pte) - return -ENOMEM; - set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); - } - pte = pte_offset_kernel(pmd, vaddr); - - paddr = __pa(vaddr); - set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot)); - - return 0; -} - static int __init acpi_mp_setup_reset(u64 reset_vector) { struct x86_mapping_info info = { @@ -130,6 +78,7 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) .page_flag = __PAGE_KERNEL_LARGE_EXEC, .kernpg_flag = _KERNPG_TABLE_NOENC, }; + unsigned long mstart, mend; pgd_t *pgd; pgd = alloc_pgt_page(NULL); @@ -137,8 +86,6 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) return -ENOMEM; for (int i = 0; i < nr_pfn_mapped; i++) { - unsigned long mstart, mend; - mstart = pfn_mapped[i].start << PAGE_SHIFT; mend = pfn_mapped[i].end << PAGE_SHIFT; if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) { @@ -147,14 +94,24 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) } } - if (kernel_ident_mapping_init(&info, pgd, - PAGE_ALIGN_DOWN(reset_vector), - PAGE_ALIGN(reset_vector + 1))) { + mstart = PAGE_ALIGN_DOWN(reset_vector); + mend = mstart + PAGE_SIZE; + if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) { kernel_ident_mapping_free(&info, pgd); return -ENOMEM; } - if (init_transition_pgtable(pgd)) { + /* + * Make sure asm_acpi_mp_play_dead() is present in the identity mapping + * at the same place as in the kernel page tables. + * asm_acpi_mp_play_dead() switches to the identity mapping and the + * function has be present at the same spot in the virtual address space + * before and after switching page tables. + */ + info.offset = __START_KERNEL_map - phys_base; + mstart = PAGE_ALIGN_DOWN(__pa(asm_acpi_mp_play_dead)); + mend = mstart + PAGE_SIZE; + if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) { kernel_ident_mapping_free(&info, pgd); return -ENOMEM; }