Make it possible to use alternatives in the vDSO, so that better
implementations can be used if possible.
Signed-off-by: Jisheng Zhang <[email protected]>
Reviewed-by: Guo Ren <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
---
arch/riscv/include/asm/vdso.h | 4 ++++
arch/riscv/kernel/alternative.c | 25 +++++++++++++++++++++++++
arch/riscv/kernel/vdso.c | 5 -----
arch/riscv/kernel/vdso/vdso.lds.S | 7 +++++++
4 files changed, 36 insertions(+), 5 deletions(-)
diff --git a/arch/riscv/include/asm/vdso.h b/arch/riscv/include/asm/vdso.h
index a7644f46d0e5..f891478829a5 100644
--- a/arch/riscv/include/asm/vdso.h
+++ b/arch/riscv/include/asm/vdso.h
@@ -28,8 +28,12 @@
#define COMPAT_VDSO_SYMBOL(base, name) \
(void __user *)((unsigned long)(base) + compat__vdso_##name##_offset)
+extern char compat_vdso_start[], compat_vdso_end[];
+
#endif /* CONFIG_COMPAT */
+extern char vdso_start[], vdso_end[];
+
#endif /* !__ASSEMBLY__ */
#endif /* CONFIG_MMU */
diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c
index 3d4f1f32c7f6..a883a309139f 100644
--- a/arch/riscv/kernel/alternative.c
+++ b/arch/riscv/kernel/alternative.c
@@ -11,7 +11,9 @@
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <asm/alternative.h>
+#include <asm/module.h>
#include <asm/sections.h>
+#include <asm/vdso.h>
#include <asm/vendorid_list.h>
#include <asm/sbi.h>
#include <asm/csr.h>
@@ -160,6 +162,27 @@ static void __init_or_module _apply_alternatives(struct alt_entry *begin,
stage);
}
+static void __init apply_vdso_alternatives(void)
+{
+ const struct elf64_hdr *hdr;
+ const struct elf64_shdr *shdr;
+ const struct elf64_shdr *alt;
+ struct alt_entry *begin, *end;
+
+ hdr = (struct elf64_hdr *)vdso_start;
+ shdr = (void *)hdr + hdr->e_shoff;
+ alt = find_section(hdr, shdr, ".alternative");
+ if (!alt)
+ return;
+
+ begin = (void *)hdr + alt->sh_offset,
+ end = (void *)hdr + alt->sh_offset + alt->sh_size,
+
+ _apply_alternatives((struct alt_entry *)begin,
+ (struct alt_entry *)end,
+ RISCV_ALTERNATIVES_BOOT);
+}
+
void __init apply_boot_alternatives(void)
{
/* If called on non-boot cpu things could go wrong */
@@ -168,6 +191,8 @@ void __init apply_boot_alternatives(void)
_apply_alternatives((struct alt_entry *)__alt_start,
(struct alt_entry *)__alt_end,
RISCV_ALTERNATIVES_BOOT);
+
+ apply_vdso_alternatives();
}
/*
diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index e410275918ac..4e631c098f4d 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -22,11 +22,6 @@ struct vdso_data {
};
#endif
-extern char vdso_start[], vdso_end[];
-#ifdef CONFIG_COMPAT
-extern char compat_vdso_start[], compat_vdso_end[];
-#endif
-
enum vvar_pages {
VVAR_DATA_PAGE_OFFSET,
VVAR_TIMENS_PAGE_OFFSET,
diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S
index 150b1a572e61..4a0606633290 100644
--- a/arch/riscv/kernel/vdso/vdso.lds.S
+++ b/arch/riscv/kernel/vdso/vdso.lds.S
@@ -40,6 +40,13 @@ SECTIONS
. = 0x800;
.text : { *(.text .text.*) } :text
+ . = ALIGN(4);
+ .alternative : {
+ __alt_start = .;
+ *(.alternative)
+ __alt_end = .;
+ }
+
.data : {
*(.got.plt) *(.got)
*(.data .data.* .gnu.linkonce.d.*)
--
2.38.1
Hi Jisheng,
I love your patch! Yet something to improve:
[auto build test ERROR on next-20230111]
[cannot apply to linus/master v6.2-rc3 v6.2-rc2 v6.2-rc1 v6.2-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jisheng-Zhang/riscv-fix-jal-offsets-in-patched-alternatives/20230112-012447
patch link: https://lore.kernel.org/r/20230111171027.2392-11-jszhang%40kernel.org
patch subject: [PATCH v3 10/13] riscv: alternative: patch alternatives in the vDSO
config: riscv-randconfig-r042-20230110
compiler: riscv64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/42cd9e915a1622a4d9332fbecb5d85c1dffbbce7
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Jisheng-Zhang/riscv-fix-jal-offsets-in-patched-alternatives/20230112-012447
git checkout 42cd9e915a1622a4d9332fbecb5d85c1dffbbce7
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
arch/riscv/kernel/alternative.c: In function 'apply_vdso_alternatives':
>> arch/riscv/kernel/alternative.c:172:35: error: 'vdso_start' undeclared (first use in this function); did you mean 'vfs_stat'?
172 | hdr = (struct elf64_hdr *)vdso_start;
| ^~~~~~~~~~
| vfs_stat
arch/riscv/kernel/alternative.c:172:35: note: each undeclared identifier is reported only once for each function it appears in
vim +172 arch/riscv/kernel/alternative.c
164
165 static void __init apply_vdso_alternatives(void)
166 {
167 const struct elf64_hdr *hdr;
168 const struct elf64_shdr *shdr;
169 const struct elf64_shdr *alt;
170 struct alt_entry *begin, *end;
171
> 172 hdr = (struct elf64_hdr *)vdso_start;
173 shdr = (void *)hdr + hdr->e_shoff;
174 alt = find_section(hdr, shdr, ".alternative");
175 if (!alt)
176 return;
177
178 begin = (void *)hdr + alt->sh_offset,
179 end = (void *)hdr + alt->sh_offset + alt->sh_size,
180
181 _apply_alternatives((struct alt_entry *)begin,
182 (struct alt_entry *)end,
183 RISCV_ALTERNATIVES_BOOT);
184 }
185
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
Hey Jisheng,
On Thu, Jan 12, 2023 at 01:10:24AM +0800, Jisheng Zhang wrote:
> Make it possible to use alternatives in the vDSO, so that better
> implementations can be used if possible.
>
> Signed-off-by: Jisheng Zhang <[email protected]>
> Reviewed-by: Guo Ren <[email protected]>
> Reviewed-by: Andrew Jones <[email protected]>
FYI, from this patch onwards the rv32 build is broken.
Should be reproduceable with the in-tree rv32_defconfig.
Unfortunately no logs for you, I've got a CI bug to fix!
Thanks,
Conor.
> ---
> arch/riscv/include/asm/vdso.h | 4 ++++
> arch/riscv/kernel/alternative.c | 25 +++++++++++++++++++++++++
> arch/riscv/kernel/vdso.c | 5 -----
> arch/riscv/kernel/vdso/vdso.lds.S | 7 +++++++
> 4 files changed, 36 insertions(+), 5 deletions(-)
>
> diff --git a/arch/riscv/include/asm/vdso.h b/arch/riscv/include/asm/vdso.h
> index a7644f46d0e5..f891478829a5 100644
> --- a/arch/riscv/include/asm/vdso.h
> +++ b/arch/riscv/include/asm/vdso.h
> @@ -28,8 +28,12 @@
> #define COMPAT_VDSO_SYMBOL(base, name) \
> (void __user *)((unsigned long)(base) + compat__vdso_##name##_offset)
>
> +extern char compat_vdso_start[], compat_vdso_end[];
> +
> #endif /* CONFIG_COMPAT */
>
> +extern char vdso_start[], vdso_end[];
> +
> #endif /* !__ASSEMBLY__ */
>
> #endif /* CONFIG_MMU */
> diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c
> index 3d4f1f32c7f6..a883a309139f 100644
> --- a/arch/riscv/kernel/alternative.c
> +++ b/arch/riscv/kernel/alternative.c
> @@ -11,7 +11,9 @@
> #include <linux/cpu.h>
> #include <linux/uaccess.h>
> #include <asm/alternative.h>
> +#include <asm/module.h>
> #include <asm/sections.h>
> +#include <asm/vdso.h>
> #include <asm/vendorid_list.h>
> #include <asm/sbi.h>
> #include <asm/csr.h>
> @@ -160,6 +162,27 @@ static void __init_or_module _apply_alternatives(struct alt_entry *begin,
> stage);
> }
>
> +static void __init apply_vdso_alternatives(void)
> +{
> + const struct elf64_hdr *hdr;
> + const struct elf64_shdr *shdr;
> + const struct elf64_shdr *alt;
> + struct alt_entry *begin, *end;
> +
> + hdr = (struct elf64_hdr *)vdso_start;
> + shdr = (void *)hdr + hdr->e_shoff;
> + alt = find_section(hdr, shdr, ".alternative");
> + if (!alt)
> + return;
> +
> + begin = (void *)hdr + alt->sh_offset,
> + end = (void *)hdr + alt->sh_offset + alt->sh_size,
> +
> + _apply_alternatives((struct alt_entry *)begin,
> + (struct alt_entry *)end,
> + RISCV_ALTERNATIVES_BOOT);
> +}
> +
> void __init apply_boot_alternatives(void)
> {
> /* If called on non-boot cpu things could go wrong */
> @@ -168,6 +191,8 @@ void __init apply_boot_alternatives(void)
> _apply_alternatives((struct alt_entry *)__alt_start,
> (struct alt_entry *)__alt_end,
> RISCV_ALTERNATIVES_BOOT);
> +
> + apply_vdso_alternatives();
> }
>
> /*
> diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
> index e410275918ac..4e631c098f4d 100644
> --- a/arch/riscv/kernel/vdso.c
> +++ b/arch/riscv/kernel/vdso.c
> @@ -22,11 +22,6 @@ struct vdso_data {
> };
> #endif
>
> -extern char vdso_start[], vdso_end[];
> -#ifdef CONFIG_COMPAT
> -extern char compat_vdso_start[], compat_vdso_end[];
> -#endif
> -
> enum vvar_pages {
> VVAR_DATA_PAGE_OFFSET,
> VVAR_TIMENS_PAGE_OFFSET,
> diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S
> index 150b1a572e61..4a0606633290 100644
> --- a/arch/riscv/kernel/vdso/vdso.lds.S
> +++ b/arch/riscv/kernel/vdso/vdso.lds.S
> @@ -40,6 +40,13 @@ SECTIONS
> . = 0x800;
> .text : { *(.text .text.*) } :text
>
> + . = ALIGN(4);
> + .alternative : {
> + __alt_start = .;
> + *(.alternative)
> + __alt_end = .;
> + }
> +
> .data : {
> *(.got.plt) *(.got)
> *(.data .data.* .gnu.linkonce.d.*)
> --
> 2.38.1
>
On Thu, Jan 12, 2023 at 07:48:29AM +0000, Conor Dooley wrote:
> Hey Jisheng,
>
> On Thu, Jan 12, 2023 at 01:10:24AM +0800, Jisheng Zhang wrote:
> > Make it possible to use alternatives in the vDSO, so that better
> > implementations can be used if possible.
> >
> > Signed-off-by: Jisheng Zhang <[email protected]>
> > Reviewed-by: Guo Ren <[email protected]>
> > Reviewed-by: Andrew Jones <[email protected]>
>
> FYI, from this patch onwards the rv32 build is broken.
> Should be reproduceable with the in-tree rv32_defconfig.
>
> Unfortunately no logs for you, I've got a CI bug to fix!
Here's the error:
../arch/riscv/kernel/alternative.c:174:21: error: incompatible pointer types passing 'const struct elf64_hdr *' to parameter of type 'const Elf32_Ehdr *' (aka 'const struct elf32_hdr *') [-Werror,-Wincompatible-pointer-types]
alt = find_section(hdr, shdr, ".alternative");
^~~
../arch/riscv/include/asm/module.h:115:60: note: passing argument to parameter 'hdr' here
static inline const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
^
../arch/riscv/kernel/alternative.c:174:26: error: incompatible pointer types passing 'const struct elf64_shdr *' to parameter of type 'const Elf32_Shdr *' (aka 'const struct elf32_shdr *') [-Werror,-Wincompatible-pointer-types]
alt = find_section(hdr, shdr, ".alternative");
^~~~
../arch/riscv/include/asm/module.h:116:25: note: passing argument to parameter 'sechdrs' here
const Elf_Shdr *sechdrs,
^
../arch/riscv/kernel/alternative.c:174:6: error: incompatible pointer types assigning to 'const struct elf64_shdr *' from 'const Elf32_Shdr *' (aka 'const struct elf32_shdr *') [-Werror,-Wincompatible-pointer-types]
alt = find_section(hdr, shdr, ".alternative");
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 errors generated.
Thanks,
Conor.