[PATCH 0/2] Let gen-vdso tool to use internal ELF header

[PATCH 0/2] Let gen-vdso tool to use internal ELF header

[Jim Shu]

Let gen-vdso tool to use QEMU's internal ELF header. It could avoid
compatibility issue of glibc version in the environment. QEMU RISC-V
zicfiss/lp extension patchset will add "EM_RISCV" symbol to it. This
symbol is not supported in the legacy glibc. 

Jim Shu (2):
  include/elf.h: align ELF macro name with glibc
  linux-user: Add QEMU include path to vdso

 include/elf.h          | 2 +-
 linux-user/meson.build | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

-- 
2.17.1

[PATCH 1/2] include/elf.h: align ELF macro name with glibc

[Jim Shu]

Rename DT_BINDNOW to DT_BIND_NOW to align with glibc header: "elf/elf.h"

Signed-off-by: Jim Shu <jim.shu@sifive.com>
---
 include/elf.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/elf.h b/include/elf.h
index e7259ec366..ef47b5e2ad 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -235,7 +235,7 @@ typedef struct mips_elf_abiflags_v0 {
 #define DT_DEBUG        21
 #define DT_TEXTREL      22
 #define DT_JMPREL       23
-#define DT_BINDNOW      24
+#define DT_BIND_NOW     24
 #define DT_INIT_ARRAY   25
 #define DT_FINI_ARRAY   26
 #define DT_INIT_ARRAYSZ 27
-- 
2.17.1

[PATCH 2/2] linux-user: Add QEMU include path to vdso

[Jim Shu]

Add include path to 'gen-vdso.c' to get ELF header in QEMU source.

Signed-off-by: Jim Shu <jim.shu@sifive.com>
---
 linux-user/meson.build | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/linux-user/meson.build b/linux-user/meson.build
index bc41e8c3bc..ccce4f7e70 100644
--- a/linux-user/meson.build
+++ b/linux-user/meson.build
@@ -30,8 +30,11 @@ linux_user_ss.add(when: 'CONFIG_ARM_COMPATIBLE_SEMIHOSTING', if_true: files('sem
 
 syscall_nr_generators = {}
 
+# It requires "include/elf.h"
+gen_vdso_inc = include_directories('..' / 'include')
 gen_vdso_exe = executable('gen-vdso', 'gen-vdso.c',
-                          native: true, build_by_default: false)
+                          native: true, build_by_default: false,
+                          include_directories: gen_vdso_inc)
 gen_vdso = generator(gen_vdso_exe, output: '@BASENAME@.c.inc',
                      arguments: ['-o', '@OUTPUT@', '@EXTRA_ARGS@', '@INPUT@'])
 
-- 
2.17.1

Re: [PATCH 1/2] include/elf.h: align ELF macro name with glibc

[Richard Henderson]

On 7/26/24 14:32, Jim Shu wrote:
> Rename DT_BINDNOW to DT_BIND_NOW to align with glibc header: "elf/elf.h"
> 
> Signed-off-by: Jim Shu<jim.shu@sifive.com>
> ---
>   include/elf.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [PATCH 0/2] Let gen-vdso tool to use internal ELF header

[Richard Henderson]

On 7/26/24 14:32, Jim Shu wrote:
> Let gen-vdso tool to use QEMU's internal ELF header. It could avoid
> compatibility issue of glibc version in the environment. QEMU RISC-V
> zicfiss/lp extension patchset will add "EM_RISCV" symbol to it. This
> symbol is not supported in the legacy glibc.

I see EM_RISCV added added (by myself, amusingly, as part of a bulk merge) in 2016, 
included in glibc 2.24.

 From repology, vs our oldest supported OS,

centos stream 8:   2.28
debian 11:         2.31
fedora 39:         2.37
opensuse leap 15:  2.28
ubuntu 20.04:      2.31

So unless there's some *other* symbol you require, all supported OS will have EM_RISCV.


r~

Re: [PATCH 2/2] linux-user: Add QEMU include path to vdso

[Richard Henderson]

On 7/26/24 14:32, Jim Shu wrote:
> Add include path to 'gen-vdso.c' to get ELF header in QEMU source.
> 
> Signed-off-by: Jim Shu <jim.shu@sifive.com>
> ---
>   linux-user/meson.build | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/linux-user/meson.build b/linux-user/meson.build
> index bc41e8c3bc..ccce4f7e70 100644
> --- a/linux-user/meson.build
> +++ b/linux-user/meson.build
> @@ -30,8 +30,11 @@ linux_user_ss.add(when: 'CONFIG_ARM_COMPATIBLE_SEMIHOSTING', if_true: files('sem
>   
>   syscall_nr_generators = {}
>   
> +# It requires "include/elf.h"
> +gen_vdso_inc = include_directories('..' / 'include')
>   gen_vdso_exe = executable('gen-vdso', 'gen-vdso.c',
> -                          native: true, build_by_default: false)
> +                          native: true, build_by_default: false,
> +                          include_directories: gen_vdso_inc)
>   gen_vdso = generator(gen_vdso_exe, output: '@BASENAME@.c.inc',
>                        arguments: ['-o', '@OUTPUT@', '@EXTRA_ARGS@', '@INPUT@'])
>   

Ok, I guess.  I'm not convinced we need this.  I tend to think our elf.h is way out of 
date, and perhaps should be removed.  I suspect we only carry it around now for windows 
hosts, compiling the system loaders.


r~

Re: [PATCH 0/2] Let gen-vdso tool to use internal ELF header

[Jim Shu]

Hi Richard,

Thanks for your feedback.
I think it is reasonable. I will drop this patchset.


Regards,
Jim Shu

On Fri, Jul 26, 2024 at 1:28 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 7/26/24 14:32, Jim Shu wrote:
> > Let gen-vdso tool to use QEMU's internal ELF header. It could avoid
> > compatibility issue of glibc version in the environment. QEMU RISC-V
> > zicfiss/lp extension patchset will add "EM_RISCV" symbol to it. This
> > symbol is not supported in the legacy glibc.
>
> I see EM_RISCV added added (by myself, amusingly, as part of a bulk merge) in 2016,
> included in glibc 2.24.
>
>  From repology, vs our oldest supported OS,
>
> centos stream 8:   2.28
> debian 11:         2.31
> fedora 39:         2.37
> opensuse leap 15:  2.28
> ubuntu 20.04:      2.31
>
> So unless there's some *other* symbol you require, all supported OS will have EM_RISCV.
>
>
> r~