powerpc/lib: Add helper to check if offset is within conditional branch range

Add a helper to check if a given offset is within the branch range for a
powerpc conditional branch instruction, and update some sites to use the
new helper.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/442b69a34ced32ca346a0d9a855f3f6cfdbbbd41.1633464148.git.naveen.n.rao@linux.vnet.ibm.com

diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h
index a95f63788c6b1423e957f7e89871987f541b62b1..4ba834599c4d4c68bea72c13dd2a07f3a0db3c91 100644 (file)
--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -23,6 +23,7 @@
 #define BRANCH_ABSOLUTE        0x2
 
 bool is_offset_in_branch_range(long offset);
+bool is_offset_in_cond_branch_range(long offset);
 int create_branch(struct ppc_inst *instr, const u32 *addr,
                  unsigned long target, int flags);
 int create_cond_branch(struct ppc_inst *instr, const u32 *addr,

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index f9a3019e37b43cfffb66e23f882d6314dfd2ae39..c5ed9882383521ec65c30a96cbc09037e9624ae3 100644 (file)
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -228,6 +228,11 @@ bool is_offset_in_branch_range(long offset)
        return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));
 }
 
+bool is_offset_in_cond_branch_range(long offset)
+{
+       return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);
+}
+
 /*
  * Helper to check if a given instruction is a conditional branch
  * Derived from the conditional checks in analyse_instr()
@@ -280,7 +285,7 @@ int create_cond_branch(struct ppc_inst *instr, const u32 *addr,
                offset = offset - (unsigned long)addr;
 
        /* Check we can represent the target in the instruction format */
-       if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3)
+       if (!is_offset_in_cond_branch_range(offset))
                return 1;
 
        /* Mask out the flags and target, so they don't step on each other. */

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index 99fad093f43ec105775d1983edfa85a37e0d1f5c..935ea95b66359ebc0483762cf02c602a1019f311 100644 (file)
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -78,11 +78,6 @@
 #define PPC_FUNC_ADDR(d,i) do { PPC_LI32(d, i); } while(0)
 #endif
 
-static inline bool is_nearbranch(int offset)
-{
-       return (offset < 32768) && (offset >= -32768);
-}
-
 /*
  * The fly in the ointment of code size changing from pass to pass is
  * avoided by padding the short branch case with a NOP.         If code size differs
@@ -91,7 +86,7 @@ static inline bool is_nearbranch(int offset)
  * state.
  */
 #define PPC_BCC(cond, dest)    do {                                          \
-               if (is_nearbranch((dest) - (ctx->idx * 4))) {                 \
+               if (is_offset_in_cond_branch_range((long)(dest) - (ctx->idx * 4))) {    \
                        PPC_BCC_SHORT(cond, dest);                            \
                        EMIT(PPC_RAW_NOP());                                  \
                } else {                                                      \