diff mbox series

[v2,2/3] riscv: Add hwprobe vdso call support

Message ID 20230221191537.3159966-3-evan@rivosinc.com
State Superseded
Headers
Series RISC-V: ifunced memcpy using new kernel hwprobe interface |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Evan Green Feb. 21, 2023, 7:15 p.m. UTC 
  The new riscv_hwprobe syscall also comes with a vDSO for faster answers
to your most common questions. Call in today to speak with a kernel
representative near you!

Signed-off-by: Evan Green <evan@rivosinc.com>
---

Changes in v2:
 - Add vDSO interface

 sysdeps/unix/sysv/linux/dl-vdso-setup.c | 10 ++++++++++
 sysdeps/unix/sysv/linux/dl-vdso-setup.h |  3 +++
 sysdeps/unix/sysv/linux/riscv/hwprobe.c |  6 ++++++
 sysdeps/unix/sysv/linux/riscv/sysdep.h  |  1 +
 4 files changed, 20 insertions(+)

Comments

Adhemerval Zanella Netto March 29, 2023, 6:39 p.m. UTC | #1 
On 21/02/23 16:15, Evan Green wrote:
> The new riscv_hwprobe syscall also comes with a vDSO for faster answers
> to your most common questions. Call in today to speak with a kernel
> representative near you!
> 
> Signed-off-by: Evan Green <evan@rivosinc.com>
> ---
> 
> Changes in v2:
>  - Add vDSO interface
> 
>  sysdeps/unix/sysv/linux/dl-vdso-setup.c | 10 ++++++++++
>  sysdeps/unix/sysv/linux/dl-vdso-setup.h |  3 +++
>  sysdeps/unix/sysv/linux/riscv/hwprobe.c |  6 ++++++
>  sysdeps/unix/sysv/linux/riscv/sysdep.h  |  1 +
>  4 files changed, 20 insertions(+)
> 
> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> index 68fa8de641..3fe304a0c7 100644
> --- a/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> @@ -71,6 +71,16 @@ PROCINFO_CLASS int (*_dl_vdso_clock_getres_time64) (clockid_t,
>  # ifdef HAVE_GET_TBFREQ
>  PROCINFO_CLASS uint64_t (*_dl_vdso_get_tbfreq)(void) RELRO;
>  # endif
> +
> +/* RISC-V specific ones.  */
> +# ifdef HAVE_RISCV_HWPROBE
> +PROCINFO_CLASS int (*_dl_vdso_riscv_hwprobe)(void *,
> +                                             long,
> +                                             long,
> +                                             unsigned long *,
> +                                             long) RELRO;
> +# endif
> +
>  #endif
>  
>  #undef RELRO
> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.h b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
> index 867072b897..39eafd5316 100644
> --- a/sysdeps/unix/sysv/linux/dl-vdso-setup.h
> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
> @@ -47,6 +47,9 @@ setup_vdso_pointers (void)
>  #ifdef HAVE_GET_TBFREQ
>    GLRO(dl_vdso_get_tbfreq) = dl_vdso_vsym (HAVE_GET_TBFREQ);
>  #endif
> +#ifdef HAVE_RISCV_HWPROBE
> +  GLRO(dl_vdso_riscv_hwprobe) = dl_vdso_vsym (HAVE_RISCV_HWPROBE);
> +#endif
>  }
>  
>  #endif
> diff --git a/sysdeps/unix/sysv/linux/riscv/hwprobe.c b/sysdeps/unix/sysv/linux/riscv/hwprobe.c
> index 74f68889ca..2c61a67db7 100644
> --- a/sysdeps/unix/sysv/linux/riscv/hwprobe.c
> +++ b/sysdeps/unix/sysv/linux/riscv/hwprobe.c
> @@ -20,11 +20,17 @@
>  #include <sys/syscall.h>
>  #include <sys/hwprobe.h>
>  #include <sysdep.h>
> +#include <sysdep-vdso.h>
>  
>  int
>  __riscv_hwprobe (struct riscv_hwprobe *pairs, long pair_count,
>    long cpu_count, unsigned long *cpus, unsigned long flags)
>  {
> + /* The vDSO may be able to provide the answer without a syscall. */
> +#ifdef HAVE_RISCV_HWPROBE
> +  INLINE_VSYSCALL(riscv_hwprobe, 5, pairs, pair_count, cpu_count, cpus, flags);
> +#else
>    return INLINE_SYSCALL_CALL (riscv_hwprobe, pairs, pair_count,
>                           cpu_count, cpus, flags);
> +#endif
>  }

The HAVE_RISCV_HWPROBE is always defined for RISCV, so there is no need
to use the fallback (INLINE_VSYSCALL already issues the syscall if the
dl_vdso_get_tbfreq is NULL). 

> diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
> index 4af5fe5dbc..ba17aaaff2 100644
> --- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
> @@ -155,6 +155,7 @@
>  /* List of system calls which are supported as vsyscalls (for RV32 and
>     RV64).  */
>  # define HAVE_GETCPU_VSYSCALL		"__vdso_getcpu"
> +# define HAVE_RISCV_HWPROBE		"__vdso_riscv_hwprobe"
>  
>  # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
>  # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
diff mbox series

Patch

diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
index 68fa8de641..3fe304a0c7 100644
--- a/sysdeps/unix/sysv/linux/dl-vdso-setup.c
+++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
@@ -71,6 +71,16 @@  PROCINFO_CLASS int (*_dl_vdso_clock_getres_time64) (clockid_t,
 # ifdef HAVE_GET_TBFREQ
 PROCINFO_CLASS uint64_t (*_dl_vdso_get_tbfreq)(void) RELRO;
 # endif
+
+/* RISC-V specific ones.  */
+# ifdef HAVE_RISCV_HWPROBE
+PROCINFO_CLASS int (*_dl_vdso_riscv_hwprobe)(void *,
+                                             long,
+                                             long,
+                                             unsigned long *,
+                                             long) RELRO;
+# endif
+
 #endif
 
 #undef RELRO
diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.h b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
index 867072b897..39eafd5316 100644
--- a/sysdeps/unix/sysv/linux/dl-vdso-setup.h
+++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
@@ -47,6 +47,9 @@  setup_vdso_pointers (void)
 #ifdef HAVE_GET_TBFREQ
   GLRO(dl_vdso_get_tbfreq) = dl_vdso_vsym (HAVE_GET_TBFREQ);
 #endif
+#ifdef HAVE_RISCV_HWPROBE
+  GLRO(dl_vdso_riscv_hwprobe) = dl_vdso_vsym (HAVE_RISCV_HWPROBE);
+#endif
 }
 
 #endif
diff --git a/sysdeps/unix/sysv/linux/riscv/hwprobe.c b/sysdeps/unix/sysv/linux/riscv/hwprobe.c
index 74f68889ca..2c61a67db7 100644
--- a/sysdeps/unix/sysv/linux/riscv/hwprobe.c
+++ b/sysdeps/unix/sysv/linux/riscv/hwprobe.c
@@ -20,11 +20,17 @@ 
 #include <sys/syscall.h>
 #include <sys/hwprobe.h>
 #include <sysdep.h>
+#include <sysdep-vdso.h>
 
 int
 __riscv_hwprobe (struct riscv_hwprobe *pairs, long pair_count,
   long cpu_count, unsigned long *cpus, unsigned long flags)
 {
+ /* The vDSO may be able to provide the answer without a syscall. */
+#ifdef HAVE_RISCV_HWPROBE
+  INLINE_VSYSCALL(riscv_hwprobe, 5, pairs, pair_count, cpu_count, cpus, flags);
+#else
   return INLINE_SYSCALL_CALL (riscv_hwprobe, pairs, pair_count,
                          cpu_count, cpus, flags);
+#endif
 }
diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
index 4af5fe5dbc..ba17aaaff2 100644
--- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
@@ -155,6 +155,7 @@ 
 /* List of system calls which are supported as vsyscalls (for RV32 and
    RV64).  */
 # define HAVE_GETCPU_VSYSCALL		"__vdso_getcpu"
+# define HAVE_RISCV_HWPROBE		"__vdso_riscv_hwprobe"
 
 # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
 # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1