Merge tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull vdso data page handling updates from Thomas Gleixner:
 "First steps of consolidating the VDSO data page handling.

  The VDSO data page handling is architecture specific for historical
  reasons, but there is no real technical reason to do so.

  Aside of that VDSO data has become a dump ground for various
  mechanisms and fail to provide a clear separation of the
  functionalities.

  Clean this up by:

   - consolidating the VDSO page data by getting rid of architecture
     specific warts especially in x86 and PowerPC.

   - removing the last includes of header files which are pulling in
     other headers outside of the VDSO namespace.

   - seperating timekeeping and other VDSO data accordingly.

  Further consolidation of the VDSO page handling is done in subsequent
  changes scheduled for the next merge window.

  This also lays the ground for expanding the VDSO time getters for
  independent PTP clocks in a generic way without making every
  architecture add support seperately"

* tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
  x86/vdso: Add missing brackets in switch case
  vdso: Rename struct arch_vdso_data to arch_vdso_time_data
  powerpc: Split systemcfg struct definitions out from vdso
  powerpc: Split systemcfg data out of vdso data page
  powerpc: Add kconfig option for the systemcfg page
  powerpc/pseries/lparcfg: Use num_possible_cpus() for potential processors
  powerpc/pseries/lparcfg: Fix printing of system_active_processors
  powerpc/procfs: Propagate error of remap_pfn_range()
  powerpc/vdso: Remove offset comment from 32bit vdso_arch_data
  x86/vdso: Split virtual clock pages into dedicated mapping
  x86/vdso: Delete vvar.h
  x86/vdso: Access vdso data without vvar.h
  x86/vdso: Move the rng offset to vsyscall.h
  x86/vdso: Access rng vdso data without vvar.h
  x86/vdso: Access timens vdso data without vvar.h
  x86/vdso: Allocate vvar page from C code
  x86/vdso: Access rng data from kernel without vvar
  x86/vdso: Place vdso_data at beginning of vvar page
  x86/vdso: Use __arch_get_vdso_data() to access vdso data
  x86/mm/mmap: Remove arch_vma_name()
  ...

3 files changed, 15 insertions, 33 deletions

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 706c9c3a7a50..e8ed8e5b713b 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -19,7 +19,6 @@
 #include <linux/signal.h>
 #include <linux/slab.h>
 #include <linux/time_namespace.h>
-#include <linux/timekeeper_internal.h>
 #include <linux/vmalloc.h>
 #include <vdso/datapage.h>
 #include <vdso/helpers.h>
@@ -39,8 +38,6 @@ struct vdso_abi_info {
 	const char *vdso_code_start;
 	const char *vdso_code_end;
 	unsigned long vdso_pages;
-	/* Data Mapping */
-	struct vm_special_mapping *dm;
 	/* Code Mapping */
 	struct vm_special_mapping *cm;
 };
@@ -113,6 +110,8 @@ struct vdso_data *arch_get_vdso_data(void *vvar_page)
 	return (struct vdso_data *)(vvar_page);
 }
 
+static const struct vm_special_mapping vvar_map;
+
 /*
  * The vvar mapping contains data for a specific time namespace, so when a task
  * changes namespace we must unmap its vvar data for the old namespace.
@@ -129,12 +128,8 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
 	mmap_read_lock(mm);
 
 	for_each_vma(vmi, vma) {
-		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm))
-			zap_vma_pages(vma);
-#ifdef CONFIG_COMPAT_VDSO
-		if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm))
+		if (vma_is_special_mapping(vma, &vvar_map))
 			zap_vma_pages(vma);
-#endif
 	}
 
 	mmap_read_unlock(mm);
@@ -176,6 +171,11 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 	return vmf_insert_pfn(vma, vmf->address, pfn);
 }
 
+static const struct vm_special_mapping vvar_map = {
+	.name   = "[vvar]",
+	.fault = vvar_fault,
+};
+
 static int __setup_additional_pages(enum vdso_abi abi,
 				    struct mm_struct *mm,
 				    struct linux_binprm *bprm,
@@ -199,7 +199,7 @@ static int __setup_additional_pages(enum vdso_abi abi,
 
 	ret = _install_special_mapping(mm, vdso_base, VVAR_NR_PAGES * PAGE_SIZE,
 				       VM_READ|VM_MAYREAD|VM_PFNMAP,
-				       vdso_info[abi].dm);
+				       &vvar_map);
 	if (IS_ERR(ret))
 		goto up_fail;
 
@@ -229,7 +229,6 @@ up_fail:
 enum aarch32_map {
 	AA32_MAP_VECTORS, /* kuser helpers */
 	AA32_MAP_SIGPAGE,
-	AA32_MAP_VVAR,
 	AA32_MAP_VDSO,
 };
 
@@ -254,10 +253,6 @@ static struct vm_special_mapping aarch32_vdso_maps[] = {
 		.pages	= &aarch32_sig_page,
 		.mremap	= aarch32_sigpage_mremap,
 	},
-	[AA32_MAP_VVAR] = {
-		.name = "[vvar]",
-		.fault = vvar_fault,
-	},
 	[AA32_MAP_VDSO] = {
 		.name = "[vdso]",
 		.mremap = vdso_mremap,
@@ -307,7 +302,6 @@ static int __init __aarch32_alloc_vdso_pages(void)
 	if (!IS_ENABLED(CONFIG_COMPAT_VDSO))
 		return 0;
 
-	vdso_info[VDSO_ABI_AA32].dm = &aarch32_vdso_maps[AA32_MAP_VVAR];
 	vdso_info[VDSO_ABI_AA32].cm = &aarch32_vdso_maps[AA32_MAP_VDSO];
 
 	return __vdso_init(VDSO_ABI_AA32);
@@ -402,26 +396,14 @@ out:
 }
 #endif /* CONFIG_COMPAT */
 
-enum aarch64_map {
-	AA64_MAP_VVAR,
-	AA64_MAP_VDSO,
-};
-
-static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = {
-	[AA64_MAP_VVAR] = {
-		.name	= "[vvar]",
-		.fault = vvar_fault,
-	},
-	[AA64_MAP_VDSO] = {
-		.name	= "[vdso]",
-		.mremap = vdso_mremap,
-	},
+static struct vm_special_mapping aarch64_vdso_map __ro_after_init = {
+	.name	= "[vdso]",
+	.mremap = vdso_mremap,
 };
 
 static int __init vdso_init(void)
 {
-	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
-	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];
+	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_map;
 
 	return __vdso_init(VDSO_ABI_AA64);
 }
diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
index f204a9ddc833..4ec32e86a8da 100644
--- a/arch/arm64/kernel/vdso/vdso.lds.S
+++ b/arch/arm64/kernel/vdso/vdso.lds.S
@@ -25,7 +25,7 @@ SECTIONS
 #ifdef CONFIG_TIME_NS
 	PROVIDE(_timens_data = _vdso_data + PAGE_SIZE);
 #endif
-	. = VDSO_LBASE + SIZEOF_HEADERS;
+	. = SIZEOF_HEADERS;
 
 	.hash		: { *(.hash) }			:text
 	.gnu.hash	: { *(.gnu.hash) }
diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S
index 8d95d7d35057..732702a187e9 100644
--- a/arch/arm64/kernel/vdso32/vdso.lds.S
+++ b/arch/arm64/kernel/vdso32/vdso.lds.S
@@ -22,7 +22,7 @@ SECTIONS
 #ifdef CONFIG_TIME_NS
 	PROVIDE_HIDDEN(_timens_data = _vdso_data + PAGE_SIZE);
 #endif
-	. = VDSO_LBASE + SIZEOF_HEADERS;
+	. = SIZEOF_HEADERS;
 
 	.hash		: { *(.hash) }			:text
 	.gnu.hash	: { *(.gnu.hash) }