On 19/10/2024 15:16, Thomas Weißschuh wrote: > On 2024-10-14 11:58:51+0100, Ryan Roberts wrote: >> Increase alignment of sections in nvhe hyp, vdso and final vmlinux image >> from PAGE_SIZE to PAGE_SIZE_MAX. For compile-time PAGE_SIZE, >> PAGE_SIZE_MAX == PAGE_SIZE so there is no change. For boot-time >> PAGE_SIZE, PAGE_SIZE_MAX is the largest selectable page size. >> >> For a boot-time page size build, image size is comparable to a 64K page >> size compile-time build. In future, it may be desirable to optimize >> run-time memory consumption by freeing unused padding pages when the >> boot-time selected page size is less than PAGE_SIZE_MAX. >> >> Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx> >> --- >> >> ***NOTE*** >> Any confused maintainers may want to read the cover note here for context: >> https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@xxxxxxx/ >> >> arch/arm64/include/asm/memory.h | 4 +-- >> arch/arm64/kernel/vdso-wrap.S | 4 +-- >> arch/arm64/kernel/vdso.c | 7 +++--- >> arch/arm64/kernel/vdso/vdso.lds.S | 4 +-- >> arch/arm64/kernel/vdso32-wrap.S | 4 +-- >> arch/arm64/kernel/vdso32/vdso.lds.S | 4 +-- >> arch/arm64/kernel/vmlinux.lds.S | 38 ++++++++++++++--------------- >> arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 2 +- >> 8 files changed, 34 insertions(+), 33 deletions(-) > >> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c >> index 89b6e78400023..1efe98909a2e0 100644 >> --- a/arch/arm64/kernel/vdso.c >> +++ b/arch/arm64/kernel/vdso.c >> @@ -195,7 +195,7 @@ static int __setup_additional_pages(enum vdso_abi abi, >> >> vdso_text_len = vdso_info[abi].vdso_pages << PAGE_SHIFT; >> /* Be sure to map the data page */ >> - vdso_mapping_len = vdso_text_len + VVAR_NR_PAGES * PAGE_SIZE; >> + vdso_mapping_len = vdso_text_len + VVAR_NR_PAGES * PAGE_SIZE_MAX; >> >> vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); >> if (IS_ERR_VALUE(vdso_base)) { >> @@ -203,7 +203,8 @@ static int __setup_additional_pages(enum vdso_abi abi, >> goto up_fail; >> } >> >> - ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE, >> + ret = _install_special_mapping(mm, vdso_base, >> + VVAR_NR_PAGES * PAGE_SIZE_MAX, >> VM_READ|VM_MAYREAD|VM_PFNMAP, >> vdso_info[abi].dm); >> if (IS_ERR(ret)) >> @@ -212,7 +213,7 @@ static int __setup_additional_pages(enum vdso_abi abi, >> if (system_supports_bti_kernel()) >> gp_flags = VM_ARM64_BTI; >> >> - vdso_base += VVAR_NR_PAGES * PAGE_SIZE; >> + vdso_base += VVAR_NR_PAGES * PAGE_SIZE_MAX; >> mm->context.vdso = (void *)vdso_base; >> ret = _install_special_mapping(mm, vdso_base, vdso_text_len, >> VM_READ|VM_EXEC|gp_flags| > >> diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S >> index 45354f2ddf706..f7d1537a689e8 100644 >> --- a/arch/arm64/kernel/vdso/vdso.lds.S >> +++ b/arch/arm64/kernel/vdso/vdso.lds.S >> @@ -18,9 +18,9 @@ OUTPUT_ARCH(aarch64) >> >> SECTIONS >> { >> - PROVIDE(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE); >> + PROVIDE(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE_MAX); >> #ifdef CONFIG_TIME_NS >> - PROVIDE(_timens_data = _vdso_data + PAGE_SIZE); >> + PROVIDE(_timens_data = _vdso_data + PAGE_SIZE_MAX); > > This looks like it also needs a change to vvar_fault() in vdso.c. > The symbols are now always PAGE_SIZE_MAX apart, while vvar_fault() works > in page offsets (vmf->pgoff) that are based on the runtime PAGE_SIZE and > it expects hardcoded offsets. > > As test you can use tools/testing/selftests/timens/timens. > > (I can't test this right now, so it's only a suspicion) Ahh good spot - that test does infact fail. This fixes the problem: ---8<--- diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 1efe98909a2e0..d2049ba6b19f5 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -151,10 +151,11 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) { + pgoff_t pgmaxoff = vmf->pgoff >> (PAGE_SHIFT_MAX - PAGE_SHIFT); struct page *timens_page = find_timens_vvar_page(vma); unsigned long pfn; - switch (vmf->pgoff) { + switch (pgmaxoff) { case VVAR_DATA_PAGE_OFFSET: if (timens_page) pfn = page_to_pfn(timens_page); ---8<--- I'll include it in the next version. Thanks, Ryan > >> #endif >> . = VDSO_LBASE + SIZEOF_HEADERS; > >> diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S >> index 8d95d7d35057d..c46d18a69d1ce 100644 >> --- a/arch/arm64/kernel/vdso32/vdso.lds.S >> +++ b/arch/arm64/kernel/vdso32/vdso.lds.S >> @@ -18,9 +18,9 @@ OUTPUT_ARCH(arm) >> >> SECTIONS >> { >> - PROVIDE_HIDDEN(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE); >> + PROVIDE_HIDDEN(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE_MAX); >> #ifdef CONFIG_TIME_NS >> - PROVIDE_HIDDEN(_timens_data = _vdso_data + PAGE_SIZE); >> + PROVIDE_HIDDEN(_timens_data = _vdso_data + PAGE_SIZE_MAX); >> #endif >> . = VDSO_LBASE + SIZEOF_HEADERS;
