Re: [PATCH v2 2/4] powerpc/bpf: implement bpf_arch_text_copy
On Thu, Mar 9, 2023 at 10:02 AM Hari Bathini wrote:
>
> bpf_arch_text_copy is used to dump JITed binary to RX page, allowing
> multiple BPF programs to share the same page. Use the newly introduced
> patch_instructions() to implement it. Around 5X improvement in speed
> of execution observed, using the new patch_instructions() function
> over patch_instruction(), while running the tests from test_bpf.ko.
>
> Signed-off-by: Hari Bathini
> ---
> arch/powerpc/net/bpf_jit_comp.c | 23 ++-
> 1 file changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> index e93aefcfb83f..0a70319116d1 100644
> --- a/arch/powerpc/net/bpf_jit_comp.c
> +++ b/arch/powerpc/net/bpf_jit_comp.c
> @@ -13,9 +13,12 @@
> #include
> #include
> #include
> -#include
> +#include
> #include
>
> +#include
> +#include
> +
> #include "bpf_jit.h"
>
> static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> @@ -272,3 +275,21 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32
> *image, int pass, struct code
> ctx->exentry_idx++;
> return 0;
> }
> +
> +void *bpf_arch_text_copy(void *dst, void *src, size_t len)
> +{
> + void *ret = ERR_PTR(-EINVAL);
> + int err;
> +
> + if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
> + return ret;
> +
> + ret = dst;
> + mutex_lock(&text_mutex);
> + err = patch_instructions(dst, src, false, len);
> + if (err)
> + ret = ERR_PTR(err);
> + mutex_unlock(&text_mutex);
> +
> + return ret;
> +}
It seems we don't really need "ret". How about something like:
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+ int err;
+
+ if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&text_mutex);
+ err = patch_instructions(dst, src, false, len);
+ mutex_unlock(&text_mutex);
+
+ return err ? ERR_PTR(err) : dst;
+}
Song
[PATCH v2 2/4] powerpc/bpf: implement bpf_arch_text_copy
bpf_arch_text_copy is used to dump JITed binary to RX page, allowing
multiple BPF programs to share the same page. Use the newly introduced
patch_instructions() to implement it. Around 5X improvement in speed
of execution observed, using the new patch_instructions() function
over patch_instruction(), while running the tests from test_bpf.ko.
Signed-off-by: Hari Bathini
---
arch/powerpc/net/bpf_jit_comp.c | 23 ++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index e93aefcfb83f..0a70319116d1 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -13,9 +13,12 @@
#include
#include
#include
-#include
+#include
#include
+#include
+#include
+
#include "bpf_jit.h"
static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
@@ -272,3 +275,21 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image,
int pass, struct code
ctx->exentry_idx++;
return 0;
}
+
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+ void *ret = ERR_PTR(-EINVAL);
+ int err;
+
+ if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+ return ret;
+
+ ret = dst;
+ mutex_lock(&text_mutex);
+ err = patch_instructions(dst, src, false, len);
+ if (err)
+ ret = ERR_PTR(err);
+ mutex_unlock(&text_mutex);
+
+ return ret;
+}
--
2.39.2
[PATCH v2 2/4] powerpc/bpf: implement bpf_arch_text_copy
bpf_arch_text_copy is used to dump JITed binary to RX page, allowing
multiple BPF programs to share the same page. Use the newly introduced
patch_instructions() to implement it. Around 5X improvement in speed
of execution observed, using the new patch_instructions() function
over patch_instruction(), while running the tests from test_bpf.ko.
Signed-off-by: Hari Bathini
---
arch/powerpc/net/bpf_jit_comp.c | 23 ++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index e93aefcfb83f..0a70319116d1 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -13,9 +13,12 @@
#include
#include
#include
-#include
+#include
#include
+#include
+#include
+
#include "bpf_jit.h"
static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
@@ -272,3 +275,21 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image,
int pass, struct code
ctx->exentry_idx++;
return 0;
}
+
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+ void *ret = ERR_PTR(-EINVAL);
+ int err;
+
+ if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+ return ret;
+
+ ret = dst;
+ mutex_lock(&text_mutex);
+ err = patch_instructions(dst, src, false, len);
+ if (err)
+ ret = ERR_PTR(err);
+ mutex_unlock(&text_mutex);
+
+ return ret;
+}
--
2.39.2
