From: Heiko Stuebner <[email protected]>
Already defined aux-vectors regarding the machine type are AT_PLATFORM
and AT_BASE_PLATFORM. PPC already uses AT_BASE_PLATFORM to identify the
real platform the system is running on, so do a similar thing on RISC-V
and export the ISA string of the running machine via this aux-vector
element.
This way userspace can possibly adapt to extensions that allow it to
run certain loads more performantly.
Signed-off-by: Heiko Stuebner <[email protected]>
---
arch/riscv/include/asm/elf.h | 10 ++++++++++
arch/riscv/kernel/cpu.c | 12 ++++++++++++
2 files changed, 22 insertions(+)
diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index 30e7d2455960..820ef627e83d 100644
--- a/arch/riscv/include/asm/elf.h
+++ b/arch/riscv/include/asm/elf.h
@@ -78,6 +78,16 @@ extern unsigned long elf_hwcap;
#define COMPAT_ELF_PLATFORM (NULL)
+/*
+ * ELF_PLATFORM indicates the ISA supported by the platform, but has
+ * special meaning to ld.so .
+ * Expose the ISA string including all usable extensions via
+ * ELF_BASE_PLATFORM instead and allow userspace to adapt to them
+ * if needed.
+ */
+#define ELF_BASE_PLATFORM (riscv_base_platform)
+extern const char *riscv_base_platform;
+
#ifdef CONFIG_MMU
#define ARCH_DLINFO \
do { \
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 06c2f587a176..71770563199f 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -118,8 +118,12 @@ static int riscv_cpuinfo_starting(unsigned int cpu)
return 0;
}
+const char *riscv_base_platform = NULL;
+static char *riscv_create_isa_string(void);
+
static int __init riscv_cpuinfo_init(void)
{
+ char *isa_str;
int ret;
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "riscv/cpuinfo:starting",
@@ -129,6 +133,14 @@ static int __init riscv_cpuinfo_init(void)
return ret;
}
+ /*
+ * Create the isa-string with the common set of extensions over
+ * all harts, to expose as AT_BASE_PLATFORM in the aux vector.
+ */
+ isa_str = riscv_create_isa_string();
+ if (!IS_ERR(isa_str))
+ riscv_base_platform = isa_str;
+
return 0;
}
arch_initcall(riscv_cpuinfo_init);
--
2.39.0
Hi Heiko,
kernel test robot noticed the following build warnings:
[auto build test WARNING on next-20230424]
[also build test WARNING on v6.3]
[cannot apply to soc/for-next linus/master kees/for-next/execve v6.3 v6.3-rc7 v6.3-rc6]
[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/Heiko-Stuebner/RISC-V-create-ISA-string-separately-not-as-part-of-cpuinfo/20230425-035214
base: next-20230424
patch link: https://lore.kernel.org/r/20230424194911.264850-4-heiko.stuebner%40vrull.eu
patch subject: [PATCH 3/4] RISC-V: export the ISA string of the running machine in the aux vector
config: riscv-randconfig-r042-20230423 (https://download.01.org/0day-ci/archive/20230425/[email protected]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 437b7602e4a998220871de78afcb020b9c14a661)
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
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/3f82c51fa0f92c257313a0291c7a36cbdfdc5bb1
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Heiko-Stuebner/RISC-V-create-ISA-string-separately-not-as-part-of-cpuinfo/20230425-035214
git checkout 3f82c51fa0f92c257313a0291c7a36cbdfdc5bb1
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kernel/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
>> arch/riscv/kernel/cpu.c:122:14: warning: function 'riscv_create_isa_string' has internal linkage but is not defined [-Wundefined-internal]
static char *riscv_create_isa_string(void);
^
arch/riscv/kernel/cpu.c:140:12: note: used here
isa_str = riscv_create_isa_string();
^
1 warning generated.
vim +/riscv_create_isa_string +122 arch/riscv/kernel/cpu.c
120
121 const char *riscv_base_platform = NULL;
> 122 static char *riscv_create_isa_string(void);
123
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
Hi Heiko,
kernel test robot noticed the following build warnings:
[auto build test WARNING on next-20230424]
[also build test WARNING on v6.3]
[cannot apply to soc/for-next linus/master kees/for-next/execve v6.3 v6.3-rc7 v6.3-rc6]
[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/Heiko-Stuebner/RISC-V-create-ISA-string-separately-not-as-part-of-cpuinfo/20230425-035214
base: next-20230424
patch link: https://lore.kernel.org/r/20230424194911.264850-4-heiko.stuebner%40vrull.eu
patch subject: [PATCH 3/4] RISC-V: export the ISA string of the running machine in the aux vector
config: riscv-randconfig-r042-20230424 (https://download.01.org/0day-ci/archive/20230425/[email protected]/config)
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/3f82c51fa0f92c257313a0291c7a36cbdfdc5bb1
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Heiko-Stuebner/RISC-V-create-ISA-string-separately-not-as-part-of-cpuinfo/20230425-035214
git checkout 3f82c51fa0f92c257313a0291c7a36cbdfdc5bb1
# 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 arch/riscv/kernel/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
>> arch/riscv/kernel/cpu.c:122:14: warning: 'riscv_create_isa_string' used but never defined
122 | static char *riscv_create_isa_string(void);
| ^~~~~~~~~~~~~~~~~~~~~~~
vim +/riscv_create_isa_string +122 arch/riscv/kernel/cpu.c
120
121 const char *riscv_base_platform = NULL;
> 122 static char *riscv_create_isa_string(void);
123
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
On Mon, Apr 24, 2023 at 09:49:10PM +0200, Heiko Stuebner wrote:
> From: Heiko Stuebner <[email protected]>
>
> Already defined aux-vectors regarding the machine type are AT_PLATFORM
> and AT_BASE_PLATFORM. PPC already uses AT_BASE_PLATFORM to identify the
> real platform the system is running on, so do a similar thing on RISC-V
> and export the ISA string of the running machine via this aux-vector
> element.
>
> This way userspace can possibly adapt to extensions that allow it to
> run certain loads more performantly.
>
> Signed-off-by: Heiko Stuebner <[email protected]>
> ---
> arch/riscv/include/asm/elf.h | 10 ++++++++++
> arch/riscv/kernel/cpu.c | 12 ++++++++++++
> 2 files changed, 22 insertions(+)
>
> diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
> index 30e7d2455960..820ef627e83d 100644
> --- a/arch/riscv/include/asm/elf.h
> +++ b/arch/riscv/include/asm/elf.h
> @@ -78,6 +78,16 @@ extern unsigned long elf_hwcap;
>
> #define COMPAT_ELF_PLATFORM (NULL)
>
> +/*
> + * ELF_PLATFORM indicates the ISA supported by the platform, but has
> + * special meaning to ld.so .
^ stray space
> + * Expose the ISA string including all usable extensions via
> + * ELF_BASE_PLATFORM instead and allow userspace to adapt to them
> + * if needed.
> + */
> +#define ELF_BASE_PLATFORM (riscv_base_platform)
> +extern const char *riscv_base_platform;
> +
> #ifdef CONFIG_MMU
> #define ARCH_DLINFO \
> do { \
> diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
> index 06c2f587a176..71770563199f 100644
> --- a/arch/riscv/kernel/cpu.c
> +++ b/arch/riscv/kernel/cpu.c
> @@ -118,8 +118,12 @@ static int riscv_cpuinfo_starting(unsigned int cpu)
> return 0;
> }
>
> +const char *riscv_base_platform = NULL;
No need for the '= NULL'
> +static char *riscv_create_isa_string(void);
> +
> static int __init riscv_cpuinfo_init(void)
> {
> + char *isa_str;
> int ret;
>
> ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "riscv/cpuinfo:starting",
> @@ -129,6 +133,14 @@ static int __init riscv_cpuinfo_init(void)
> return ret;
> }
>
> + /*
> + * Create the isa-string with the common set of extensions over
> + * all harts, to expose as AT_BASE_PLATFORM in the aux vector.
> + */
> + isa_str = riscv_create_isa_string();
> + if (!IS_ERR(isa_str))
> + riscv_base_platform = isa_str;
> +
> return 0;
> }
> arch_initcall(riscv_cpuinfo_init);
> --
> 2.39.0
>
Otherwise,
Reviewed-by: Andrew Jones <[email protected]>