Le 11/01/2022 à 15:35, Christophe Leroy a écrit :
Le 11/01/2022 à 11:31, Naveen N. Rao a écrit :
Christophe Leroy wrote:
Le 06/01/2022 à 12:45, Naveen N. Rao a écrit :
In preparation for using kernel TOC, load the same in r2 on entry. With
elfv1, the kernel TOC is already setup by our caller so we just emit a
nop. We adjust the number of instructions to skip on a tail call
accordingly.
Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/net/bpf_jit_comp64.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c
b/arch/powerpc/net/bpf_jit_comp64.c
index ce4fc59bbd6a92..e05b577d95bf11 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -73,6 +73,12 @@ void bpf_jit_build_prologue(u32 *image, struct
codegen_context *ctx)
{
int i;
+#ifdef PPC64_ELF_ABI_v2
+ PPC_BPF_LL(_R2, _R13, offsetof(struct paca_struct, kernel_toc));
+#else
+ EMIT(PPC_RAW_NOP());
+#endif
Can we avoid the #ifdef, using
if (__is_defined(PPC64_ELF_ABI_v2))
PPC_BPF_LL(_R2, _R13, offsetof(struct paca_struct, kernel_toc));
else
EMIT(PPC_RAW_NOP());
Hmm... that doesn't work for me. Is __is_defined() expected to work with
macros other than CONFIG options?
Yes, __is_defined() should work with any item.
It is IS_ENABLED() which is supposed to work only with CONFIG options.
See commit 5c189c523e78 ("powerpc/time: Fix mftb()/get_tb() for use with
the compat VDSO")
Or commit ca5999fde0a1 ("mm: introduce include/linux/pgtable.h")
Ah ... wait.
It seems it expects a macro set to 1.
So it would require arch/powerpc/include/asm/types.h to be modified to
define PPC64_ELF_ABI_v2 or PPC64_ELF_ABI_v1 as 1
Christophe
