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 4.14-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-4.14 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 03:30:35 PM CET 2021
From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Date: Mon, 15 Nov 2021 16:35:06 +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: <31c942335cc5abe56e06e1431f6285143b065f06.1636968906.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
@@ -25,6 +25,7 @@
#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
@@ -244,6 +244,11 @@ 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()
@@ -297,7 +302,7 @@ 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-4.14/powerpc-bpf-validate-branch-ranges.patch
queue-4.14/powerpc-lib-add-helper-to-check-if-offset-is-within-conditional-branch-range.patch
queue-4.14/powerpc-bpf-fix-bpf_sub-when-imm-0x80000000.patch
