| From foo@baz Mon Nov 15 03:31:49 PM CET 2021 |
| From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> |
| Date: Mon, 15 Nov 2021 16:36:00 +0530 |
| Subject: powerpc/lib: Add helper to check if offset is within conditional branch range |
| To: <stable@vger.kernel.org> |
| Cc: Michael Ellerman <mpe@ellerman.id.au>, Daniel Borkmann <daniel@iogearbox.net> |
| Message-ID: <2ea819633858eb1fb4e1563aeffa5598bd028b3d.1636963359.git.naveen.n.rao@linux.vnet.ibm.com> |
| |
| 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/442b69a34ced32ca346a0d9a855f3f6cfdbbbd41.1633464148.git.naveen.n.rao@linux.vnet.ibm.com |
| 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 |
| @@ -22,6 +22,7 @@ |
| #define BRANCH_ABSOLUTE 0x2 |
| |
| bool is_offset_in_branch_range(long offset); |
| +bool is_offset_in_cond_branch_range(long offset); |
| unsigned int create_branch(const unsigned int *addr, |
| unsigned long target, int flags); |
| unsigned int create_cond_branch(const unsigned int *addr, |
| --- a/arch/powerpc/lib/code-patching.c |
| +++ b/arch/powerpc/lib/code-patching.c |
| @@ -221,6 +221,11 @@ 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() |
| @@ -274,7 +279,7 @@ unsigned int create_cond_branch(const un |
| 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 0; |
| |
| /* 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 |
| @@ -225,11 +225,6 @@ |
| #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 |
| @@ -238,7 +233,7 @@ 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); \ |
| PPC_NOP(); \ |
| } else { \ |