From: Maxwell Bland <mbland@motorola.com>
To: "open list:BPF [GENERAL] (Safe Dynamic Programs and Tools)"
<bpf@vger.kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Zi Shen Lim <zlim.lnx@gmail.com>,
Mark Rutland <mark.rutland@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mark Brown <broonie@kernel.org>,
linux-arm-kernel@lists.infradead.org,
open list <linux-kernel@vger.kernel.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Puranjay Mohan <puranjay12@gmail.com>
Subject: [PATCH bpf-next v4 3/3] arm64/cfi,bpf: Use DEFINE_CFI_TYPE in arm64
Date: Mon, 13 May 2024 09:14:33 -0500 [thread overview]
Message-ID: <ste77mcidmsm75jvh2ss5ebaa7x4em5ekuf67wxnftzpielypx@q7gsjlbk3atx> (raw)
In-Reply-To: <wtb6czzpvtqq23t4g6hf7on257dtxzdb4fa4nuq3dtq32odmli@xoyyrtthafar>
Corrects Puranjay Mohan's commit to adopt Mark Rutland's
suggestion of using a C CFI type macro in kCFI+BPF.
Signed-off-by: Maxwell Bland <mbland@motorola.com>
---
arch/arm64/kernel/alternative.c | 46 ++++-----------------------------
1 file changed, 5 insertions(+), 41 deletions(-)
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index 1715da7df137..d7a58eca7665 100644
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -8,6 +8,7 @@
#define pr_fmt(fmt) "alternatives: " fmt
+#include <linux/cfi_types.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/elf.h>
@@ -302,53 +303,16 @@ EXPORT_SYMBOL(alt_cb_patch_nops);
#ifdef CONFIG_CFI_CLANG
struct bpf_insn;
-
/* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */
extern unsigned int __bpf_prog_runX(const void *ctx,
const struct bpf_insn *insn);
-
-/*
- * Force a reference to the external symbol so the compiler generates
- * __kcfi_typid.
- */
-__ADDRESSABLE(__bpf_prog_runX);
-
-/* u32 __ro_after_init cfi_bpf_hash = __kcfi_typeid___bpf_prog_runX; */
-asm (
-" .pushsection .data..ro_after_init,\"aw\",@progbits \n"
-" .type cfi_bpf_hash,@object \n"
-" .globl cfi_bpf_hash \n"
-" .p2align 2, 0x0 \n"
-"cfi_bpf_hash: \n"
-" .word __kcfi_typeid___bpf_prog_runX \n"
-" .size cfi_bpf_hash, 4 \n"
-" .popsection \n"
-);
-
+DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX);
/* Must match bpf_callback_t */
extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64);
-
-__ADDRESSABLE(__bpf_callback_fn);
-
-/* u32 __ro_after_init cfi_bpf_subprog_hash = __kcfi_typeid___bpf_callback_fn; */
-asm (
-" .pushsection .data..ro_after_init,\"aw\",@progbits \n"
-" .type cfi_bpf_subprog_hash,@object \n"
-" .globl cfi_bpf_subprog_hash \n"
-" .p2align 2, 0x0 \n"
-"cfi_bpf_subprog_hash: \n"
-" .word __kcfi_typeid___bpf_callback_fn \n"
-" .size cfi_bpf_subprog_hash, 4 \n"
-" .popsection \n"
-);
-
+DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn);
u32 cfi_get_func_hash(void *func)
{
- u32 hash;
-
- if (get_kernel_nofault(hash, func - cfi_get_offset()))
- return 0;
-
- return hash;
+ u32 *hashp = func - cfi_get_offset();
+ return READ_ONCE(*hashp);
}
#endif
--
2.34.1
prev parent reply other threads:[~2024-05-13 14:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-13 14:08 [PATCH bpf-next v4 0/3] Support kCFI + BPF on arm64 Maxwell Bland
2024-05-13 14:10 ` [PATCH bpf-next v4 1/3] cfi: add C CFI type macro Maxwell Bland
2024-05-13 14:12 ` [PATCH bpf-next v4 2/3] arm64/cfi,bpf: Support kCFI + BPF on arm64 Maxwell Bland
2024-05-13 16:39 ` Puranjay Mohan
2024-05-15 16:05 ` Maxwell Bland
2024-05-13 14:14 ` Maxwell Bland [this message]
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