From: "Naveen N. Rao" naveen.n.rao@linux.vnet.ibm.com
upstream commit 4549c3ea3160fa8b3f37dfe2f957657bb265eda9
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/442b69a34ced32ca346a0d9a855f3f6cfdbbbd41.163346414... Signed-off-by: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/include/asm/code-patching.h | 1 + arch/powerpc/lib/code-patching.c | 7 ++++++- arch/powerpc/net/bpf_jit.h | 7 +------ 3 files changed, 8 insertions(+), 7 deletions(-)
--- 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 struct ppc_inst *addr, unsigned long target, int flags); int create_cond_branch(struct ppc_inst *instr, const struct ppc_inst *addr, --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -230,6 +230,11 @@ bool is_offset_in_branch_range(long offs 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() @@ -283,7 +288,7 @@ int create_cond_branch(struct ppc_inst * 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. */ --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -71,11 +71,6 @@ #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 @@ -84,7 +79,7 @@ static inline bool is_nearbranch(int off * 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 { \