diff mbox series

[bpf-next] bpf: add support to read cpu_entry in bpf program

Message ID 20240427151825.174486-1-dev@der-flo.net (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series [bpf-next] bpf: add support to read cpu_entry in bpf program | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for bpf-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 2795 this patch: 1866
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 18 of 18 maintainers
netdev/build_clang fail Errors and warnings before: 1068 this patch: 130
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 2901 this patch: 1961
netdev/checkpatch warning WARNING: line length of 87 exceeds 80 columns WARNING: line length of 91 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-0 success Logs for Lint
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-3 success Logs for Validate matrix.py
bpf/vmtest-bpf-next-VM_Test-5 success Logs for aarch64-gcc / build-release
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Unittests
bpf/vmtest-bpf-next-VM_Test-4 success Logs for aarch64-gcc / build / build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for aarch64-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-18 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-28 success Logs for x86_64-llvm-17 / build / build for x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-42 success Logs for x86_64-llvm-18 / veristat
bpf/vmtest-bpf-next-VM_Test-20 success Logs for x86_64-gcc / build-release
bpf/vmtest-bpf-next-VM_Test-19 success Logs for x86_64-gcc / build / build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-35 success Logs for x86_64-llvm-18 / build / build for x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-34 success Logs for x86_64-llvm-17 / veristat
bpf/vmtest-bpf-next-VM_Test-12 success Logs for s390x-gcc / build-release
bpf/vmtest-bpf-next-VM_Test-29 success Logs for x86_64-llvm-17 / build-release / build for x86_64 with llvm-17 and -O2 optimization
bpf/vmtest-bpf-next-VM_Test-36 success Logs for x86_64-llvm-18 / build-release / build for x86_64 with llvm-18 and -O2 optimization
bpf/vmtest-bpf-next-VM_Test-11 success Logs for s390x-gcc / build / build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-17 success Logs for s390x-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-7 success Logs for aarch64-gcc / test (test_progs, false, 360) / test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-15 success Logs for s390x-gcc / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-6 success Logs for aarch64-gcc / test (test_maps, false, 360) / test_maps on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for s390x-gcc / test (test_verifier, false, 360) / test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for s390x-gcc / test (test_maps, false, 360) / test_maps on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-14 success Logs for s390x-gcc / test (test_progs, false, 360) / test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-8 success Logs for aarch64-gcc / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for aarch64-gcc / test (test_verifier, false, 360) / test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-30 success Logs for x86_64-llvm-17 / test (test_maps, false, 360) / test_maps on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-31 success Logs for x86_64-llvm-17 / test (test_progs, false, 360) / test_progs on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-23 success Logs for x86_64-gcc / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-41 success Logs for x86_64-llvm-18 / test (test_verifier, false, 360) / test_verifier on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-40 success Logs for x86_64-llvm-18 / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-39 success Logs for x86_64-llvm-18 / test (test_progs_cpuv4, false, 360) / test_progs_cpuv4 on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-22 success Logs for x86_64-gcc / test (test_progs, false, 360) / test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-37 success Logs for x86_64-llvm-18 / test (test_maps, false, 360) / test_maps on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-26 success Logs for x86_64-gcc / test (test_verifier, false, 360) / test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-27 success Logs for x86_64-gcc / veristat / veristat on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-33 success Logs for x86_64-llvm-17 / test (test_verifier, false, 360) / test_verifier on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-24 success Logs for x86_64-gcc / test (test_progs_no_alu32_parallel, true, 30) / test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-25 success Logs for x86_64-gcc / test (test_progs_parallel, true, 30) / test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-38 success Logs for x86_64-llvm-18 / test (test_progs, false, 360) / test_progs on x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-21 success Logs for x86_64-gcc / test (test_maps, false, 360) / test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-32 success Logs for x86_64-llvm-17 / test (test_progs_no_alu32, false, 360) / test_progs_no_alu32 on x86_64 with llvm-17

Commit Message

Florian Lehner April 27, 2024, 3:18 p.m. UTC 
Add new field "cpu_entry" to bpf_perf_event_data which could be read by
bpf programs attached to perf events. The value contains the CPU value
recorded by specifying sample_type with PERF_SAMPLE_CPU when calling
perf_event_open().

Signed-off-by: Florian Lehner <dev@der-flo.net>
---
 include/uapi/linux/bpf_perf_event.h       |  4 ++++
 kernel/trace/bpf_trace.c                  | 13 +++++++++++++
 tools/include/uapi/linux/bpf_perf_event.h |  4 ++++
 3 files changed, 21 insertions(+)

Comments

Yonghong Song April 29, 2024, 10:26 p.m. UTC | #1 
On 4/27/24 8:18 AM, Florian Lehner wrote:
> Add new field "cpu_entry" to bpf_perf_event_data which could be read by
> bpf programs attached to perf events. The value contains the CPU value
> recorded by specifying sample_type with PERF_SAMPLE_CPU when calling
> perf_event_open().

You can use bpf_cast_to_kern_ctx kfunc which can cast 'struct bpf_perf_event_data'
ctx to 'struct bpf_perf_event_data_kern'.

struct bpf_perf_event_data_kern {
         bpf_user_pt_regs_t *regs;
         struct perf_sample_data *data;
         struct perf_event *event;
};

You can access bpf_perf_event_data_kern->data and then to access 'cpu_entry' field.

>
> Signed-off-by: Florian Lehner <dev@der-flo.net>
> ---
>   include/uapi/linux/bpf_perf_event.h       |  4 ++++
>   kernel/trace/bpf_trace.c                  | 13 +++++++++++++
>   tools/include/uapi/linux/bpf_perf_event.h |  4 ++++
>   3 files changed, 21 insertions(+)
>
> diff --git a/include/uapi/linux/bpf_perf_event.h b/include/uapi/linux/bpf_perf_event.h
> index eb1b9d21250c..4856b4396ece 100644
> --- a/include/uapi/linux/bpf_perf_event.h
> +++ b/include/uapi/linux/bpf_perf_event.h
> @@ -14,6 +14,10 @@ struct bpf_perf_event_data {
>   	bpf_user_pt_regs_t regs;
>   	__u64 sample_period;
>   	__u64 addr;
> +	struct {
> +		u32	cpu;
> +		u32	reserved;
> +	}			cpu_entry;
>   };
>   
>   #endif /* _UAPI__LINUX_BPF_PERF_EVENT_H__ */
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index afb232b1d7c2..2b303221af5c 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2176,6 +2176,11 @@ static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type
>   		if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
>   			return false;
>   		break;
> +	case bpf_ctx_range(struct bpf_perf_event_data, cpu_entry):
> +		bpf_ctx_record_field_size(info, size_u64);
> +		if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
> +			return false;
> +		break;
>   	default:
>   		if (size != sizeof(long))
>   			return false;
> @@ -2208,6 +2213,14 @@ static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
>   				      bpf_target_off(struct perf_sample_data, addr, 8,
>   						     target_size));
>   		break;
> +	case offsetof(struct bpf_perf_event_data, cpu_entry):
> +		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
> +						       data), si->dst_reg, si->src_reg,
> +				      offsetof(struct bpf_perf_event_data_kern, data));
> +		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
> +				      bpf_target_off(struct perf_sample_data, cpu_entry, 8,
> +						     target_size));
> +		break;
>   	default:
>   		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
>   						       regs), si->dst_reg, si->src_reg,
> diff --git a/tools/include/uapi/linux/bpf_perf_event.h b/tools/include/uapi/linux/bpf_perf_event.h
> index eb1b9d21250c..4856b4396ece 100644
> --- a/tools/include/uapi/linux/bpf_perf_event.h
> +++ b/tools/include/uapi/linux/bpf_perf_event.h
> @@ -14,6 +14,10 @@ struct bpf_perf_event_data {
>   	bpf_user_pt_regs_t regs;
>   	__u64 sample_period;
>   	__u64 addr;
> +	struct {
> +		u32	cpu;
> +		u32	reserved;
> +	}			cpu_entry;
>   };
>   
>   #endif /* _UAPI__LINUX_BPF_PERF_EVENT_H__ */
diff mbox series

Patch

diff --git a/include/uapi/linux/bpf_perf_event.h b/include/uapi/linux/bpf_perf_event.h
index eb1b9d21250c..4856b4396ece 100644
--- a/include/uapi/linux/bpf_perf_event.h
+++ b/include/uapi/linux/bpf_perf_event.h
@@ -14,6 +14,10 @@  struct bpf_perf_event_data {
 	bpf_user_pt_regs_t regs;
 	__u64 sample_period;
 	__u64 addr;
+	struct {
+		u32	cpu;
+		u32	reserved;
+	}			cpu_entry;
 };
 
 #endif /* _UAPI__LINUX_BPF_PERF_EVENT_H__ */
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index afb232b1d7c2..2b303221af5c 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2176,6 +2176,11 @@  static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type
 		if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
 			return false;
 		break;
+	case bpf_ctx_range(struct bpf_perf_event_data, cpu_entry):
+		bpf_ctx_record_field_size(info, size_u64);
+		if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
+			return false;
+		break;
 	default:
 		if (size != sizeof(long))
 			return false;
@@ -2208,6 +2213,14 @@  static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
 				      bpf_target_off(struct perf_sample_data, addr, 8,
 						     target_size));
 		break;
+	case offsetof(struct bpf_perf_event_data, cpu_entry):
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
+						       data), si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_perf_event_data_kern, data));
+		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
+				      bpf_target_off(struct perf_sample_data, cpu_entry, 8,
+						     target_size));
+		break;
 	default:
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
 						       regs), si->dst_reg, si->src_reg,
diff --git a/tools/include/uapi/linux/bpf_perf_event.h b/tools/include/uapi/linux/bpf_perf_event.h
index eb1b9d21250c..4856b4396ece 100644
--- a/tools/include/uapi/linux/bpf_perf_event.h
+++ b/tools/include/uapi/linux/bpf_perf_event.h
@@ -14,6 +14,10 @@  struct bpf_perf_event_data {
 	bpf_user_pt_regs_t regs;
 	__u64 sample_period;
 	__u64 addr;
+	struct {
+		u32	cpu;
+		u32	reserved;
+	}			cpu_entry;
 };
 
 #endif /* _UAPI__LINUX_BPF_PERF_EVENT_H__ */