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Message-Id: <8a639c3cbfc03bb3158fc8897f6e2ebca2d02ab2.1598363608.git.christophe.leroy@csgroup.eu>
Date: Tue, 25 Aug 2020 13:54:06 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 8/9] powerpc/vdso: Remove __kernel_datapage_offset and
simplify __get_datapage()
The VDSO datapage and the text pages are always located immediately
next to each other, so it can be hardcoded without an indirection
through __kernel_datapage_offset
Before:
clock-getres-realtime-coarse: vdso: 714 nsec/call
clock-gettime-realtime-coarse: vdso: 792 nsec/call
clock-gettime-realtime: vdso: 1243 nsec/call
After:
clock-getres-realtime-coarse: vdso: 699 nsec/call
clock-gettime-realtime-coarse: vdso: 784 nsec/call
clock-gettime-realtime: vdso: 1231 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/include/asm/vdso_datapage.h | 8 +++--
arch/powerpc/kernel/vdso.c | 37 ------------------------
arch/powerpc/kernel/vdso32/datapage.S | 3 --
arch/powerpc/kernel/vdso32/vdso32.lds.S | 7 ++---
arch/powerpc/kernel/vdso64/datapage.S | 3 --
arch/powerpc/kernel/vdso64/vdso64.lds.S | 7 ++---
6 files changed, 9 insertions(+), 56 deletions(-)
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
index c4d320504d26..2bc415f7714c 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -104,10 +104,12 @@ extern struct vdso_arch_data *vdso_data;
.macro get_datapage ptr, tmp
bcl 20, 31, .+4
+999:
mflr \ptr
- addi \ptr, \ptr, (__kernel_datapage_offset - (.-4))@l
- lwz \tmp, 0(\ptr)
- add \ptr, \tmp, \ptr
+#if CONFIG_PPC_PAGE_SHIFT > 14
+ addis \ptr, \ptr, (_vdso_datapage - 999b)@ha
+#endif
+ addi \ptr, \ptr, (_vdso_datapage - 999b)@l
.endm
#endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 1d72c4b7672f..e2568d9ecdff 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -500,40 +500,6 @@ static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
}
-static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
- struct lib64_elfinfo *v64)
-{
-#ifdef CONFIG_VDSO32
- Elf32_Sym *sym32;
-#endif
-#ifdef CONFIG_PPC64
- Elf64_Sym *sym64;
-
- sym64 = find_symbol64(v64, "__kernel_datapage_offset");
- if (sym64 == NULL) {
- printk(KERN_ERR "vDSO64: Can't find symbol "
- "__kernel_datapage_offset !\n");
- return -1;
- }
- *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
- (sym64->st_value - VDSO64_LBASE) - PAGE_SIZE;
-#endif /* CONFIG_PPC64 */
-
-#ifdef CONFIG_VDSO32
- sym32 = find_symbol32(v32, "__kernel_datapage_offset");
- if (sym32 == NULL) {
- printk(KERN_ERR "vDSO32: Can't find symbol "
- "__kernel_datapage_offset !\n");
- return -1;
- }
- *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
- (sym32->st_value - VDSO32_LBASE) - PAGE_SIZE;
-#endif
-
- return 0;
-}
-
-
static __init int vdso_fixup_features(struct lib32_elfinfo *v32,
struct lib64_elfinfo *v64)
{
@@ -634,9 +600,6 @@ static __init int vdso_setup(void)
if (vdso_do_find_sections(&v32, &v64))
return -1;
- if (vdso_fixup_datapage(&v32, &v64))
- return -1;
-
if (vdso_fixup_features(&v32, &v64))
return -1;
diff --git a/arch/powerpc/kernel/vdso32/datapage.S b/arch/powerpc/kernel/vdso32/datapage.S
index 217bb630f8f9..5513a4f8253e 100644
--- a/arch/powerpc/kernel/vdso32/datapage.S
+++ b/arch/powerpc/kernel/vdso32/datapage.S
@@ -13,9 +13,6 @@
#include <asm/vdso_datapage.h>
.text
- .global __kernel_datapage_offset;
-__kernel_datapage_offset:
- .long 0
/*
* void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S
index 582c5b046cc9..25be27b47a9f 100644
--- a/arch/powerpc/kernel/vdso32/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S
@@ -4,6 +4,7 @@
* library
*/
#include <asm/vdso.h>
+#include <asm/page.h>
#ifdef __LITTLE_ENDIAN__
OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle")
@@ -15,6 +16,7 @@ ENTRY(_start)
SECTIONS
{
+ PROVIDE(_vdso_datapage = . - PAGE_SIZE);
. = VDSO32_LBASE + SIZEOF_HEADERS;
.hash : { *(.hash) } :text
@@ -139,11 +141,6 @@ VERSION
{
VDSO_VERSION_STRING {
global:
- /*
- * Has to be there for the kernel to find
- */
- __kernel_datapage_offset;
-
__kernel_get_syscall_map;
#ifndef CONFIG_PPC_BOOK3S_601
__kernel_gettimeofday;
diff --git a/arch/powerpc/kernel/vdso64/datapage.S b/arch/powerpc/kernel/vdso64/datapage.S
index 067247d3efb9..03bb72c440dc 100644
--- a/arch/powerpc/kernel/vdso64/datapage.S
+++ b/arch/powerpc/kernel/vdso64/datapage.S
@@ -13,9 +13,6 @@
#include <asm/vdso_datapage.h>
.text
-.global __kernel_datapage_offset;
-__kernel_datapage_offset:
- .long 0
/*
* void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S
index 4e3a8d4ee614..aaa5acf6d1b9 100644
--- a/arch/powerpc/kernel/vdso64/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S
@@ -4,6 +4,7 @@
* library
*/
#include <asm/vdso.h>
+#include <asm/page.h>
#ifdef __LITTLE_ENDIAN__
OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle")
@@ -15,6 +16,7 @@ ENTRY(_start)
SECTIONS
{
+ PROVIDE(_vdso_datapage = . - PAGE_SIZE);
. = VDSO64_LBASE + SIZEOF_HEADERS;
.hash : { *(.hash) } :text
@@ -139,11 +141,6 @@ VERSION
{
VDSO_VERSION_STRING {
global:
- /*
- * Has to be there for the kernel to find
- */
- __kernel_datapage_offset;
-
__kernel_get_syscall_map;
__kernel_gettimeofday;
__kernel_clock_gettime;
--
2.25.0
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