powerpc32/bpf: Add fsession support

Extend JIT support of fsession in powerpc64 trampoline, since
ppc64 and ppc32 shares common trampoline implementation.
Arch specific helpers handle 64-bit data copy using 32 bit regs.

Need to validate fsession support along with trampoline support.

Signed-off-by: Abhishek Dubey <adubey@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260401141043.41513-2-adubey@linux.ibm.com

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 16d15ff3145a3c341473e183c0d6a8f8ecb4bb71..b2fdf8ff9c604836595e86f84f7d0d83132b7c75 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -542,7 +542,13 @@ bool bpf_jit_supports_private_stack(void)
 
 bool bpf_jit_supports_fsession(void)
 {
-       return IS_ENABLED(CONFIG_PPC64);
+       /*
+        * TODO: Remove after validating support
+        * for fsession and trampoline on ppc32.
+        */
+       if (IS_ENABLED(CONFIG_PPC32))
+               return -EOPNOTSUPP;
+       return true;
 }
 
 bool bpf_jit_supports_arena(void)

diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index 3087e744fb25049aae5b2de27182a3a783285be3..f3ae89e1d1d0b07d96d2853e2055bad19b9d4f50 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -123,6 +123,41 @@ void bpf_jit_realloc_regs(struct codegen_context *ctx)
        }
 }
 
+void prepare_for_fsession_fentry(u32 *image, struct codegen_context *ctx, int cookie_cnt,
+                                               int cookie_off, int retval_off)
+{
+       /*
+        * Set session cookies value
+        * Clear cookies field on stack
+        * Ensure retval to be cleared on fentry
+        */
+       EMIT(PPC_RAW_LI(bpf_to_ppc(TMP_REG), 0));
+
+       for (int i = 0; i < cookie_cnt; i++) {
+               EMIT(PPC_RAW_STW(bpf_to_ppc(TMP_REG), _R1, cookie_off + 4 * i));
+               EMIT(PPC_RAW_STW(bpf_to_ppc(TMP_REG), _R1, cookie_off + 4 * i + 4));
+       }
+
+       EMIT(PPC_RAW_STW(bpf_to_ppc(TMP_REG), _R1, retval_off));
+       EMIT(PPC_RAW_STW(bpf_to_ppc(TMP_REG), _R1, retval_off + 4));
+}
+
+void store_func_meta(u32 *image, struct codegen_context *ctx,
+                                       u64 func_meta, int func_meta_off)
+{
+       /*
+        * Store func_meta to stack: [R1 + func_meta_off] = func_meta
+        * func_meta := argument count in first byte + cookie value
+        */
+       /* Store lower word */
+       EMIT(PPC_RAW_LI32(bpf_to_ppc(TMP_REG), (u32)func_meta));
+       EMIT(PPC_RAW_STW(bpf_to_ppc(TMP_REG), _R1, func_meta_off));
+
+       /* Store upper word */
+       EMIT(PPC_RAW_LI32(bpf_to_ppc(TMP_REG), (u32)(func_meta >> 32)));
+       EMIT(PPC_RAW_STW(bpf_to_ppc(TMP_REG), _R1, func_meta_off + 4));
+}
+
 void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
 {
        int i;