This is a note to let you know that I've just added the patch titled powerpc/lib: Add helper to check if offset is within conditional branch range to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-lib-add-helper-to-check-if-offset-is-within-conditional-branch-range.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Mon Nov 15 03:31:22 PM CET 2021 From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Date: Mon, 15 Nov 2021 16:35:28 +0530 Subject: powerpc/lib: Add helper to check if offset is within conditional branch range To: <stable@xxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>, Daniel Borkmann <daniel@xxxxxxxxxxxxx> Message-ID: <7b757e056b85dc60a0ab84dafb6b648d017a02ea.1636968020.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx> From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx> Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Acked-by: Song Liu <songliubraving@xxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/442b69a34ced32ca346a0d9a855f3f6cfdbbbd41.1633464148.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -26,6 +26,7 @@ #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 @@ -243,6 +243,11 @@ 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() @@ -296,7 +301,7 @@ 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 @@ -221,11 +221,6 @@ #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 @@ -234,7 +229,7 @@ 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 { \ Patches currently in stable-queue which might be from naveen.n.rao@xxxxxxxxxxxxxxxxxx are queue-4.19/powerpc-bpf-emit-stf-barrier-instruction-sequences-for-bpf_nospec.patch queue-4.19/powerpc-bpf-validate-branch-ranges.patch queue-4.19/powerpc-lib-add-helper-to-check-if-offset-is-within-conditional-branch-range.patch queue-4.19/powerpc-security-add-a-helper-to-query-stf_barrier-type.patch queue-4.19/powerpc-bpf-fix-bpf_sub-when-imm-0x80000000.patch