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Message-ID: <0557d3ec898c1d0ea2fc59fa8757618e524c5d94.1727858295.git.christophe.leroy@csgroup.eu>
Date: Wed, 2 Oct 2024 10:39:28 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Naveen N Rao <naveen@...nel.org>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org,
Jason@...c4.com
Subject: [PATCH 1/2] 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 <christophe.leroy@...roup.eu>
---
arch/powerpc/include/asm/vdso_datapage.h | 24 +++++++-----------------
arch/powerpc/kernel/vdso.c | 16 ++++++++++------
arch/powerpc/kernel/vdso/cacheflush.S | 2 +-
arch/powerpc/kernel/vdso/datapage.S | 4 ++--
arch/powerpc/kernel/vdso/getrandom.S | 3 +--
arch/powerpc/kernel/vdso/gettimeofday.S | 5 ++---
arch/powerpc/kernel/vdso/vdso32.lds.S | 2 +-
arch/powerpc/kernel/vdso/vdso64.lds.S | 2 +-
8 files changed, 25 insertions(+), 33 deletions(-)
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
index 248dee138f7b..33069afccb3c 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -82,8 +82,9 @@ struct vdso_arch_data {
__u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */
__u32 compat_syscall_map[SYSCALL_MAP_SIZE]; /* Map of compat syscalls */
- struct vdso_data data[CS_BASES];
struct vdso_rng_data rng_data;
+
+ struct vdso_data data[CS_BASES] __aligned(1 << CONFIG_PAGE_SHIFT);
};
#else /* CONFIG_PPC64 */
@@ -95,8 +96,9 @@ struct vdso_arch_data {
__u64 tb_ticks_per_sec; /* Timebase tics / sec 0x38 */
__u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */
__u32 compat_syscall_map[0]; /* No compat syscalls on PPC32 */
- struct vdso_data data[CS_BASES];
struct vdso_rng_data rng_data;
+
+ struct vdso_data data[CS_BASES] __aligned(1 << CONFIG_PAGE_SHIFT);
};
#endif /* CONFIG_PPC64 */
@@ -105,29 +107,17 @@ extern struct vdso_arch_data *vdso_data;
#else /* __ASSEMBLY__ */
-.macro get_datapage ptr
+.macro get_datapage ptr offset=0
bcl 20, 31, .+4
999:
mflr \ptr
- addis \ptr, \ptr, (_vdso_datapage - 999b)@ha
- addi \ptr, \ptr, (_vdso_datapage - 999b)@l
+ addis \ptr, \ptr, (_vdso_datapage - 999b + \offset)@ha
+ addi \ptr, \ptr, (_vdso_datapage - 999b + \offset)@l
.endm
#include <asm/asm-offsets.h>
#include <asm/page.h>
-.macro get_realdatapage ptr scratch
- get_datapage \ptr
-#ifdef CONFIG_TIME_NS
- lwz \scratch, VDSO_CLOCKMODE_OFFSET(\ptr)
- xoris \scratch, \scratch, VDSO_CLOCKMODE_TIMENS@h
- xori \scratch, \scratch, VDSO_CLOCKMODE_TIMENS@l
- cntlzw \scratch, \scratch
- rlwinm \scratch, \scratch, PAGE_SHIFT - 5, 1 << PAGE_SHIFT
- add \ptr, \ptr, \scratch
-#endif
-.endm
-
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
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:
diff --git a/arch/powerpc/kernel/vdso/cacheflush.S b/arch/powerpc/kernel/vdso/cacheflush.S
index 3b2479bd2f9a..0085ae464dac 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_realdatapage r10, r11
+ get_datapage r10
mtlr r12
.cfi_restore lr
#endif
diff --git a/arch/powerpc/kernel/vdso/datapage.S b/arch/powerpc/kernel/vdso/datapage.S
index 2b19b6201a33..db8e167f0166 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_realdatapage r3, r11
+ get_datapage r3
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_realdatapage r3, r11
+ get_datapage r3
#ifndef __powerpc64__
lwz r4,(CFG_TB_TICKS_PER_SEC + 4)(r3)
#endif
diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S
index f3bbf931931c..3deddcf89f99 100644
--- a/arch/powerpc/kernel/vdso/getrandom.S
+++ b/arch/powerpc/kernel/vdso/getrandom.S
@@ -31,8 +31,7 @@
PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1)
.cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
#endif
- get_realdatapage r8, r11
- addi r8, r8, VDSO_RNG_DATA_OFFSET
+ get_datapage r8 VDSO_RNG_DATA_OFFSET
bl CFUNC(DOTSYM(\funct))
PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
#ifdef __powerpc64__
diff --git a/arch/powerpc/kernel/vdso/gettimeofday.S b/arch/powerpc/kernel/vdso/gettimeofday.S
index 5540d7021fa2..5333848322ca 100644
--- a/arch/powerpc/kernel/vdso/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso/gettimeofday.S
@@ -32,11 +32,10 @@
PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1)
.cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
#endif
- get_datapage r5
.ifeq \call_time
- addi r5, r5, VDSO_DATA_OFFSET
+ get_datapage r5 VDSO_DATA_OFFSET
.else
- addi r4, r5, VDSO_DATA_OFFSET
+ get_datapage r4 VDSO_DATA_OFFSET
.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 7b41d5d256e8..1a1b0b6d681a 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -16,7 +16,7 @@ OUTPUT_ARCH(powerpc:common)
SECTIONS
{
- PROVIDE(_vdso_datapage = . - 2 * PAGE_SIZE);
+ PROVIDE(_vdso_datapage = . - 3 * PAGE_SIZE);
. = SIZEOF_HEADERS;
.hash : { *(.hash) } :text
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index 9481e4b892ed..e21b5506cad6 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -16,7 +16,7 @@ OUTPUT_ARCH(powerpc:common64)
SECTIONS
{
- PROVIDE(_vdso_datapage = . - 2 * PAGE_SIZE);
+ PROVIDE(_vdso_datapage = . - 3 * PAGE_SIZE);
. = SIZEOF_HEADERS;
.hash : { *(.hash) } :text
--
2.44.0
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