From c39b1dcf055d420a498d1047c645b776e4d1a7aa Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Wed, 2 Oct 2024 10:39:28 +0200 Subject: powerpc/vdso: Add a page for non-time data The page containing VDSO time data is swapped with the one containing TIME namespace data when a process uses a non-root time namespace. For other data like powerpc specific data and RNG data, it means tracking whether time namespace is the root one or not to know which page to use. Simplify the logic behind by moving time data out of first data page so that the first data page which contains everything else always remains the first page. Time data is in the second or third page depending on selected time namespace. While we are playing with get_datapage macro, directly take into account the data offset inside the macro instead of adding that offset afterwards. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://patch.msgid.link/0557d3ec898c1d0ea2fc59fa8757618e524c5d94.1727858295.git.christophe.leroy@csgroup.eu --- arch/powerpc/kernel/vdso.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'arch/powerpc/kernel/vdso.c') diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index ee4b9d676cff..6166c1862c06 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -48,12 +48,13 @@ long sys_ni_syscall(void); */ static union { struct vdso_arch_data data; - u8 page[PAGE_SIZE]; + u8 page[2 * PAGE_SIZE]; } vdso_data_store __page_aligned_data; struct vdso_arch_data *vdso_data = &vdso_data_store.data; enum vvar_pages { - VVAR_DATA_PAGE_OFFSET, + VVAR_BASE_PAGE_OFFSET, + VVAR_TIME_PAGE_OFFSET, VVAR_TIMENS_PAGE_OFFSET, VVAR_NR_PAGES, }; @@ -119,7 +120,7 @@ static struct vm_special_mapping vdso64_spec __ro_after_init = { #ifdef CONFIG_TIME_NS struct vdso_data *arch_get_vdso_data(void *vvar_page) { - return ((struct vdso_arch_data *)vvar_page)->data; + return vvar_page; } /* @@ -153,11 +154,14 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, unsigned long pfn; switch (vmf->pgoff) { - case VVAR_DATA_PAGE_OFFSET: + case VVAR_BASE_PAGE_OFFSET: + pfn = virt_to_pfn(vdso_data); + break; + case VVAR_TIME_PAGE_OFFSET: if (timens_page) pfn = page_to_pfn(timens_page); else - pfn = virt_to_pfn(vdso_data); + pfn = virt_to_pfn(vdso_data->data); break; #ifdef CONFIG_TIME_NS case VVAR_TIMENS_PAGE_OFFSET: @@ -170,7 +174,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, */ if (!timens_page) return VM_FAULT_SIGBUS; - pfn = virt_to_pfn(vdso_data); + pfn = virt_to_pfn(vdso_data->data); break; #endif /* CONFIG_TIME_NS */ default: -- cgit