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riscv: vdso: Switch to generic storage implementation

Browse Source 
The generic storage implementation provides the same features as the
custom one. However it can be shared between architectures, making
maintenance easier.

Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-9-13a4669dfc8c@linutronix.de
This commit is contained in:
Thomas Weißschuh 2025-02-04 13:05:41 +01:00 committed by Thomas Gleixner
parent 0b3bc3354e
commit 46fe55b204
9 changed files with 18 additions and 124 deletions
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3
arch/riscv/Kconfig
View File

@ -53,7 +53,7 @@ config RISCV
select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UBSAN
select ARCH_HAS_VDSO_TIME_DATA
select ARCH_HAS_VDSO_ARCH_DATA if GENERIC_VDSO_DATA_STORE
select ARCH_KEEP_MEMBLOCK if ACPI
select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE if 64BIT && MMU
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
@ -116,6 +116,7 @@ config RISCV
select GENERIC_SCHED_CLOCK
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL if MMU && 64BIT
select GENERIC_VDSO_DATA_STORE if MMU
select GENERIC_VDSO_TIME_NS if HAVE_GENERIC_VDSO
select HARDIRQS_SW_RESEND
select HAS_IOPORT if MMU

2
arch/riscv/include/asm/vdso.h
View File

@ -14,7 +14,7 @@
*/
#ifdef CONFIG_MMU
#define __VVAR_PAGES 2
#define __VDSO_PAGES 4
#ifndef __ASSEMBLY__
#include <generated/vdso-offsets.h>

8
arch/riscv/include/asm/vdso/time_data.h → arch/riscv/include/asm/vdso/arch_data.h
View File

@ -1,12 +1,12 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __RISCV_ASM_VDSO_TIME_DATA_H
#define __RISCV_ASM_VDSO_TIME_DATA_H
#ifndef __RISCV_ASM_VDSO_ARCH_DATA_H
#define __RISCV_ASM_VDSO_ARCH_DATA_H
#include <linux/types.h>
#include <vdso/datapage.h>
#include <asm/hwprobe.h>
struct arch_vdso_time_data {
struct vdso_arch_data {
/* Stash static answers to the hwprobe queries when all CPUs are selected. */
__u64 all_cpu_hwprobe_values[RISCV_HWPROBE_MAX_KEY + 1];
@ -14,4 +14,4 @@ struct arch_vdso_time_data {
__u8 homogeneous_cpus;
};
#endif /* __RISCV_ASM_VDSO_TIME_DATA_H */
#endif /* __RISCV_ASM_VDSO_ARCH_DATA_H */

14
arch/riscv/include/asm/vdso/gettimeofday.h
View File

@ -69,7 +69,7 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
#endif /* CONFIG_GENERIC_TIME_VSYSCALL */
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
const struct vdso_time_data *vd)
{
/*
* The purpose of csr_read(CSR_TIME) is to trap the system into
@ -79,18 +79,6 @@ static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
return csr_read(CSR_TIME);
}
static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
{
return _vdso_data;
}
#ifdef CONFIG_TIME_NS
static __always_inline
const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
{
return _timens_data;
}
#endif
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_VDSO_GETTIMEOFDAY_H */

9
arch/riscv/include/asm/vdso/vsyscall.h
View File

@ -6,15 +6,6 @@
#include <vdso/datapage.h>
extern struct vdso_data *vdso_data;
static __always_inline struct vdso_data *__riscv_get_k_vdso_data(void)
{
return vdso_data;
}
#define __arch_get_k_vdso_data __riscv_get_k_vdso_data
/* The asm-generic header needs to be included after the definitions above */
#include <asm-generic/vdso/vsyscall.h>

3
arch/riscv/kernel/sys_hwprobe.c
View File

@ -450,8 +450,7 @@ static int do_riscv_hwprobe(struct riscv_hwprobe __user *pairs,
static int __init init_hwprobe_vdso_data(void)
{
struct vdso_data *vd = __arch_get_k_vdso_data();
struct arch_vdso_time_data *avd = &vd->arch_data;
struct vdso_arch_data *avd = vdso_k_arch_data;
u64 id_bitsmash = 0;
struct riscv_hwprobe pair;
int key;

90
arch/riscv/kernel/vdso.c
View File

@ -13,20 +13,11 @@
#include <linux/err.h>
#include <asm/page.h>
#include <asm/vdso.h>
#include <linux/time_namespace.h>
#include <linux/vdso_datastore.h>
#include <vdso/datapage.h>
#include <vdso/vsyscall.h>
enum vvar_pages {
VVAR_DATA_PAGE_OFFSET,
VVAR_TIMENS_PAGE_OFFSET,
VVAR_NR_PAGES,
};
#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)
static union vdso_data_store vdso_data_store __page_aligned_data;
struct vdso_data *vdso_data = vdso_data_store.data;
#define VVAR_SIZE (VDSO_NR_PAGES << PAGE_SHIFT)
struct __vdso_info {
const char *name;
@ -79,78 +70,6 @@ static void __init __vdso_init(struct __vdso_info *vdso_info)
vdso_info->cm->pages = vdso_pagelist;
}
#ifdef CONFIG_TIME_NS
struct vdso_data *arch_get_vdso_data(void *vvar_page)
{
return (struct vdso_data *)(vvar_page);
}
static const struct vm_special_mapping rv_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.
* 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;
struct vm_area_struct *vma;
VMA_ITERATOR(vmi, mm, 0);
mmap_read_lock(mm);
for_each_vma(vmi, vma) {
if (vma_is_special_mapping(vma, &rv_vvar_map))
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_DATA_PAGE_OFFSET:
if (timens_page)
pfn = page_to_pfn(timens_page);
else
pfn = sym_to_pfn(vdso_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 = sym_to_pfn(vdso_data);
break;
#endif /* CONFIG_TIME_NS */
default:
return VM_FAULT_SIGBUS;
}
return vmf_insert_pfn(vma, vmf->address, pfn);
}
static const struct vm_special_mapping rv_vvar_map = {
.name = "[vvar]",
.fault = vvar_fault,
};
static struct vm_special_mapping rv_vdso_map __ro_after_init = {
.name = "[vdso]",
.mremap = vdso_mremap,
@ -196,7 +115,7 @@ static int __setup_additional_pages(struct mm_struct *mm,
unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
void *ret;
BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);
BUILD_BUG_ON(VDSO_NR_PAGES != __VDSO_PAGES);
vdso_text_len = vdso_info->vdso_pages << PAGE_SHIFT;
/* Be sure to map the data page */
@ -208,8 +127,7 @@ static int __setup_additional_pages(struct mm_struct *mm,
goto up_fail;
}
ret = _install_special_mapping(mm, vdso_base, VVAR_SIZE,
(VM_READ | VM_MAYREAD | VM_PFNMAP), &rv_vvar_map);
ret = vdso_install_vvar_mapping(mm, vdso_base);
if (IS_ERR(ret))
goto up_fail;

6
arch/riscv/kernel/vdso/hwprobe.c
View File

@ -16,8 +16,7 @@ static int riscv_vdso_get_values(struct riscv_hwprobe *pairs, size_t pair_count,
size_t cpusetsize, unsigned long *cpus,
unsigned int flags)
{
const struct vdso_data *vd = __arch_get_vdso_data();
const struct arch_vdso_time_data *avd = &vd->arch_data;
const struct vdso_arch_data *avd = &vdso_u_arch_data;
bool all_cpus = !cpusetsize && !cpus;
struct riscv_hwprobe *p = pairs;
struct riscv_hwprobe *end = pairs + pair_count;
@ -51,8 +50,7 @@ static int riscv_vdso_get_cpus(struct riscv_hwprobe *pairs, size_t pair_count,
size_t cpusetsize, unsigned long *cpus,
unsigned int flags)
{
const struct vdso_data *vd = __arch_get_vdso_data();
const struct arch_vdso_time_data *avd = &vd->arch_data;
const struct vdso_arch_data *avd = &vdso_u_arch_data;
struct riscv_hwprobe *p = pairs;
struct riscv_hwprobe *end = pairs + pair_count;
unsigned char *c = (unsigned char *)cpus;

7
arch/riscv/kernel/vdso/vdso.lds.S
View File

@ -4,15 +4,14 @@
*/
#include <asm/page.h>
#include <asm/vdso.h>
#include <vdso/datapage.h>
OUTPUT_ARCH(riscv)
SECTIONS
{
PROVIDE(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE);
#ifdef CONFIG_TIME_NS
PROVIDE(_timens_data = _vdso_data + PAGE_SIZE);
#endif
VDSO_VVAR_SYMS
. = SIZEOF_HEADERS;
.hash : { *(.hash) } :text