Merge tag 'timers-vdso-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull VDSO infrastructure updates from Thomas Gleixner:

 - Consolidate the VDSO storage

   The VDSO data storage and data layout has been largely architecture
   specific for historical reasons. That increases the maintenance
   effort and causes inconsistencies over and over.

   There is no real technical reason for architecture specific layouts
   and implementations. The architecture specific details can easily be
   integrated into a generic layout, which also reduces the amount of
   duplicated code for managing the mappings.

   Convert all architectures over to a unified layout and common mapping
   infrastructure. This splits the VDSO data layout into subsystem
   specific blocks, timekeeping, random and architecture parts, which
   provides a better structure and allows to improve and update the
   functionalities without conflict and interaction.

 - Rework the timekeeping data storage

   The current implementation is designed for exposing system
   timekeeping accessors, which was good enough at the time when it was
   designed.

   PTP and Time Sensitive Networking (TSN) change that as there are
   requirements to expose independent PTP clocks, which are not related
   to system timekeeping.

   Replace the monolithic data storage by a structured layout, which
   allows to add support for independent PTP clocks on top while reusing
   both the data structures and the time accessor implementations.

* tag 'timers-vdso-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
  sparc/vdso: Always reject undefined references during linking
  x86/vdso: Always reject undefined references during linking
  vdso: Rework struct vdso_time_data and introduce struct vdso_clock
  vdso: Move architecture related data before basetime data
  powerpc/vdso: Prepare introduction of struct vdso_clock
  arm64/vdso: Prepare introduction of struct vdso_clock
  x86/vdso: Prepare introduction of struct vdso_clock
  time/namespace: Prepare introduction of struct vdso_clock
  vdso/namespace: Rename timens_setup_vdso_data() to reflect new vdso_clock struct
  vdso/vsyscall: Prepare introduction of struct vdso_clock
  vdso/gettimeofday: Prepare helper functions for introduction of struct vdso_clock
  vdso/gettimeofday: Prepare do_coarse_timens() for introduction of struct vdso_clock
  vdso/gettimeofday: Prepare do_coarse() for introduction of struct vdso_clock
  vdso/gettimeofday: Prepare do_hres_timens() for introduction of struct vdso_clock
  vdso/gettimeofday: Prepare do_hres() for introduction of struct vdso_clock
  vdso/gettimeofday: Prepare introduction of struct vdso_clock
  vdso/helpers: Prepare introduction of struct vdso_clock
  vdso/datapage: Define vdso_clock to prepare for multiple PTP clocks
  vdso: Make vdso_time_data cacheline aligned
  arm64: Make asm/cache.h compatible with vDSO
  ...

10 files changed, 31 insertions, 121 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 7a390bd4f4af..b3048f6d3822 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -334,7 +334,6 @@ int main(void)
 #endif /* ! CONFIG_PPC64 */
 
 	/* datapage offsets for use by vdso */
-	OFFSET(VDSO_DATA_OFFSET, vdso_arch_data, data);
 	OFFSET(CFG_TB_TICKS_PER_SEC, vdso_arch_data, tb_ticks_per_sec);
 #ifdef CONFIG_PPC64
 	OFFSET(CFG_ICACHE_BLOCKSZ, vdso_arch_data, icache_block_size);
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 0727332ad86f..15784c5c95c7 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -950,7 +950,7 @@ void __init time_init(void)
 		sys_tz.tz_dsttime = 0;
 	}
 
-	vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
+	vdso_k_arch_data->tb_ticks_per_sec = tb_ticks_per_sec;
 #ifdef CONFIG_PPC64_PROC_SYSTEMCFG
 	systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
 #endif
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 43379365ce1b..219d67bcf747 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -17,7 +17,7 @@
 #include <linux/elf.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
-#include <linux/time_namespace.h>
+#include <linux/vdso_datastore.h>
 #include <vdso/datapage.h>
 
 #include <asm/syscall.h>
@@ -32,6 +32,8 @@
 #include <asm/vdso_datapage.h>
 #include <asm/setup.h>
 
+static_assert(__VDSO_PAGES == VDSO_NR_PAGES);
+
 /* The alignment of the vDSO */
 #define VDSO_ALIGNMENT	(1 << 16)
 
@@ -40,24 +42,6 @@ extern char vdso64_start, vdso64_end;
 
 long sys_ni_syscall(void);
 
-/*
- * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
- * Once the early boot kernel code no longer needs to muck around
- * with it, it will become dynamically allocated
- */
-static union {
-	struct vdso_arch_data	data;
-	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_BASE_PAGE_OFFSET,
-	VVAR_TIME_PAGE_OFFSET,
-	VVAR_TIMENS_PAGE_OFFSET,
-	VVAR_NR_PAGES,
-};
-
 static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma,
 		       unsigned long text_size)
 {
@@ -96,14 +80,6 @@ static void vdso_close(const struct vm_special_mapping *sm, struct vm_area_struc
 	mm->context.vdso = NULL;
 }
 
-static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
-			     struct vm_area_struct *vma, struct vm_fault *vmf);
-
-static struct vm_special_mapping vvar_spec __ro_after_init = {
-	.name = "[vvar]",
-	.fault = vvar_fault,
-};
-
 static struct vm_special_mapping vdso32_spec __ro_after_init = {
 	.name = "[vdso]",
 	.mremap = vdso32_mremap,
@@ -116,73 +92,6 @@ static struct vm_special_mapping vdso64_spec __ro_after_init = {
 	.close = vdso_close,
 };
 
-#ifdef CONFIG_TIME_NS
-struct vdso_data *arch_get_vdso_data(void *vvar_page)
-{
-	return vvar_page;
-}
-
-/*
- * 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.
- * Subsequent faults will map in data for the new namespace.
- *
- * For more details see timens_setup_vdso_data().
- */
-int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
-{
-	struct mm_struct *mm = task->mm;
-	VMA_ITERATOR(vmi, mm, 0);
-	struct vm_area_struct *vma;
-
-	mmap_read_lock(mm);
-	for_each_vma(vmi, vma) {
-		if (vma_is_special_mapping(vma, &vvar_spec))
-			zap_vma_pages(vma);
-	}
-	mmap_read_unlock(mm);
-
-	return 0;
-}
-#endif
-
-static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
-			     struct vm_area_struct *vma, struct vm_fault *vmf)
-{
-	struct page *timens_page = find_timens_vvar_page(vma);
-	unsigned long pfn;
-
-	switch (vmf->pgoff) {
-	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->data);
-		break;
-#ifdef CONFIG_TIME_NS
-	case VVAR_TIMENS_PAGE_OFFSET:
-		/*
-		 * If a task belongs to a time namespace then a namespace
-		 * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
-		 * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
-		 * offset.
-		 * See also the comment near timens_setup_vdso_data().
-		 */
-		if (!timens_page)
-			return VM_FAULT_SIGBUS;
-		pfn = virt_to_pfn(vdso_data->data);
-		break;
-#endif /* CONFIG_TIME_NS */
-	default:
-		return VM_FAULT_SIGBUS;
-	}
-
-	return vmf_insert_pfn(vma, vmf->address, pfn);
-}
-
 /*
  * This is called from binfmt_elf, we create the special vma for the
  * vDSO and insert it into the mm struct tree
@@ -191,7 +100,7 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
 {
 	unsigned long vdso_size, vdso_base, mappings_size;
 	struct vm_special_mapping *vdso_spec;
-	unsigned long vvar_size = VVAR_NR_PAGES * PAGE_SIZE;
+	unsigned long vvar_size = VDSO_NR_PAGES * PAGE_SIZE;
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 
@@ -217,9 +126,7 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
 	/* Add required alignment. */
 	vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
 
-	vma = _install_special_mapping(mm, vdso_base, vvar_size,
-				       VM_READ | VM_MAYREAD | VM_IO |
-				       VM_DONTDUMP | VM_PFNMAP, &vvar_spec);
+	vma = vdso_install_vvar_mapping(mm, vdso_base);
 	if (IS_ERR(vma))
 		return PTR_ERR(vma);
 
@@ -299,10 +206,10 @@ static void __init vdso_setup_syscall_map(void)
 
 	for (i = 0; i < NR_syscalls; i++) {
 		if (sys_call_table[i] != (void *)&sys_ni_syscall)
-			vdso_data->syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
+			vdso_k_arch_data->syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
 		if (IS_ENABLED(CONFIG_COMPAT) &&
 		    compat_sys_call_table[i] != (void *)&sys_ni_syscall)
-			vdso_data->compat_syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
+			vdso_k_arch_data->compat_syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
 	}
 }
 
@@ -352,10 +259,10 @@ static struct page ** __init vdso_setup_pages(void *start, void *end)
 static int __init vdso_init(void)
 {
 #ifdef CONFIG_PPC64
-	vdso_data->dcache_block_size = ppc64_caches.l1d.block_size;
-	vdso_data->icache_block_size = ppc64_caches.l1i.block_size;
-	vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
-	vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
+	vdso_k_arch_data->dcache_block_size = ppc64_caches.l1d.block_size;
+	vdso_k_arch_data->icache_block_size = ppc64_caches.l1i.block_size;
+	vdso_k_arch_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
+	vdso_k_arch_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
 #endif /* CONFIG_PPC64 */
 
 	vdso_setup_syscall_map();
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 0e3ed6fb199f..e8824f933326 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -3,7 +3,7 @@
 # List of files in the vdso, has to be asm only for now
 
 # Include the generic Makefile to check the built vdso.
-include $(srctree)/lib/vdso/Makefile
+include $(srctree)/lib/vdso/Makefile.include
 
 obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o
 obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o
diff --git a/arch/powerpc/kernel/vdso/cacheflush.S b/arch/powerpc/kernel/vdso/cacheflush.S
index 0085ae464dac..488d3ade11e6 100644
--- a/arch/powerpc/kernel/vdso/cacheflush.S
+++ b/arch/powerpc/kernel/vdso/cacheflush.S
@@ -30,7 +30,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
 #ifdef CONFIG_PPC64
 	mflr	r12
   .cfi_register lr,r12
-	get_datapage	r10
+	get_datapage	r10 vdso_u_arch_data
 	mtlr	r12
   .cfi_restore	lr
 #endif
diff --git a/arch/powerpc/kernel/vdso/datapage.S b/arch/powerpc/kernel/vdso/datapage.S
index db8e167f0166..d23b2e8e2a34 100644
--- a/arch/powerpc/kernel/vdso/datapage.S
+++ b/arch/powerpc/kernel/vdso/datapage.S
@@ -28,7 +28,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map)
 	mflr	r12
   .cfi_register lr,r12
 	mr.	r4,r3
-	get_datapage	r3
+	get_datapage	r3 vdso_u_arch_data
 	mtlr	r12
 #ifdef __powerpc64__
 	addi	r3,r3,CFG_SYSCALL_MAP64
@@ -52,7 +52,7 @@ V_FUNCTION_BEGIN(__kernel_get_tbfreq)
   .cfi_startproc
 	mflr	r12
   .cfi_register lr,r12
-	get_datapage	r3
+	get_datapage	r3 vdso_u_arch_data
 #ifndef __powerpc64__
 	lwz	r4,(CFG_TB_TICKS_PER_SEC + 4)(r3)
 #endif
diff --git a/arch/powerpc/kernel/vdso/gettimeofday.S b/arch/powerpc/kernel/vdso/gettimeofday.S
index 5333848322ca..79c967212444 100644
--- a/arch/powerpc/kernel/vdso/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso/gettimeofday.S
@@ -33,9 +33,9 @@
   .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
 #endif
 	.ifeq	\call_time
-		get_datapage	r5 VDSO_DATA_OFFSET
+		get_datapage	r5 vdso_u_time_data
 	.else
-		get_datapage	r4 VDSO_DATA_OFFSET
+		get_datapage	r4 vdso_u_time_data
 	.endif
 	bl		CFUNC(DOTSYM(\funct))
 	PPC_LL		r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 1a1b0b6d681a..72a1012b8a20 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -6,6 +6,7 @@
 #include <asm/vdso.h>
 #include <asm/page.h>
 #include <asm-generic/vmlinux.lds.h>
+#include <vdso/datapage.h>
 
 #ifdef __LITTLE_ENDIAN__
 OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle")
@@ -16,7 +17,8 @@ OUTPUT_ARCH(powerpc:common)
 
 SECTIONS
 {
-	PROVIDE(_vdso_datapage = . - 3 * PAGE_SIZE);
+	VDSO_VVAR_SYMS
+
 	. = SIZEOF_HEADERS;
 
 	.hash          	: { *(.hash) }			:text
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index e21b5506cad6..32102a05eaa7 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -6,6 +6,7 @@
 #include <asm/vdso.h>
 #include <asm/page.h>
 #include <asm-generic/vmlinux.lds.h>
+#include <vdso/datapage.h>
 
 #ifdef __LITTLE_ENDIAN__
 OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle")
@@ -16,7 +17,8 @@ OUTPUT_ARCH(powerpc:common64)
 
 SECTIONS
 {
-	PROVIDE(_vdso_datapage = . - 3 * PAGE_SIZE);
+	VDSO_VVAR_SYMS
+
 	. = SIZEOF_HEADERS;
 
 	.hash		: { *(.hash) }			:text
diff --git a/arch/powerpc/kernel/vdso/vgettimeofday.c b/arch/powerpc/kernel/vdso/vgettimeofday.c
index 55a287c9a736..6f5167d81af5 100644
--- a/arch/powerpc/kernel/vdso/vgettimeofday.c
+++ b/arch/powerpc/kernel/vdso/vgettimeofday.c
@@ -7,43 +7,43 @@
 
 #ifdef __powerpc64__
 int __c_kernel_clock_gettime(clockid_t clock, struct __kernel_timespec *ts,
-			     const struct vdso_data *vd)
+			     const struct vdso_time_data *vd)
 {
 	return __cvdso_clock_gettime_data(vd, clock, ts);
 }
 
 int __c_kernel_clock_getres(clockid_t clock_id, struct __kernel_timespec *res,
-			    const struct vdso_data *vd)
+			    const struct vdso_time_data *vd)
 {
 	return __cvdso_clock_getres_data(vd, clock_id, res);
 }
 #else
 int __c_kernel_clock_gettime(clockid_t clock, struct old_timespec32 *ts,
-			     const struct vdso_data *vd)
+			     const struct vdso_time_data *vd)
 {
 	return __cvdso_clock_gettime32_data(vd, clock, ts);
 }
 
 int __c_kernel_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts,
-			       const struct vdso_data *vd)
+			       const struct vdso_time_data *vd)
 {
 	return __cvdso_clock_gettime_data(vd, clock, ts);
 }
 
 int __c_kernel_clock_getres(clockid_t clock_id, struct old_timespec32 *res,
-			    const struct vdso_data *vd)
+			    const struct vdso_time_data *vd)
 {
 	return __cvdso_clock_getres_time32_data(vd, clock_id, res);
 }
 #endif
 
 int __c_kernel_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz,
-			    const struct vdso_data *vd)
+			    const struct vdso_time_data *vd)
 {
 	return __cvdso_gettimeofday_data(vd, tv, tz);
 }
 
-__kernel_old_time_t __c_kernel_time(__kernel_old_time_t *time, const struct vdso_data *vd)
+__kernel_old_time_t __c_kernel_time(__kernel_old_time_t *time, const struct vdso_time_data *vd)
 {
 	return __cvdso_time_data(vd, time);
 }