[PATCH 4/4] samples/bpf: Enable powerpc support
From: Naveen N. Rao <hidden>
Date: 2016-03-31 11:27:44
Also in:
lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Add the necessary definitions for building bpf samples on ppc. Since ppc doesn't store function return address on the stack, modify how PT_REGS_RET() and PT_REGS_FP() work. Also, introduce PT_REGS_IP() to access the instruction pointer. I have fixed this to work with x86_64 and arm64, but not s390. Cc: Alexei Starovoitov <redacted> Cc: David S. Miller <davem@davemloft.net> Cc: Ananth N Mavinakayanahalli <redacted> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Naveen N. Rao <redacted> --- samples/bpf/bpf_helpers.h | 26 ++++++++++++++++++++++++++ samples/bpf/spintest_kern.c | 2 +- samples/bpf/tracex2_kern.c | 4 ++-- samples/bpf/tracex4_kern.c | 2 +- 4 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h
index 9363500..343423c 100644
--- a/samples/bpf/bpf_helpers.h
+++ b/samples/bpf/bpf_helpers.h@@ -82,6 +82,7 @@ static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flag #define PT_REGS_FP(x) ((x)->bp) #define PT_REGS_RC(x) ((x)->ax) #define PT_REGS_SP(x) ((x)->sp) +#define PT_REGS_IP(x) ((x)->ip) #elif defined(__s390x__)
@@ -94,6 +95,7 @@ static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flag #define PT_REGS_FP(x) ((x)->gprs[11]) /* Works only with CONFIG_FRAME_POINTER */ #define PT_REGS_RC(x) ((x)->gprs[2]) #define PT_REGS_SP(x) ((x)->gprs[15]) +#define PT_REGS_IP(x) ((x)->ip) #elif defined(__aarch64__)
@@ -106,6 +108,30 @@ static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flag #define PT_REGS_FP(x) ((x)->regs[29]) /* Works only with CONFIG_FRAME_POINTER */ #define PT_REGS_RC(x) ((x)->regs[0]) #define PT_REGS_SP(x) ((x)->sp) +#define PT_REGS_IP(x) ((x)->pc) + +#elif defined(__powerpc__) + +#define PT_REGS_PARM1(x) ((x)->gpr[3]) +#define PT_REGS_PARM2(x) ((x)->gpr[4]) +#define PT_REGS_PARM3(x) ((x)->gpr[5]) +#define PT_REGS_PARM4(x) ((x)->gpr[6]) +#define PT_REGS_PARM5(x) ((x)->gpr[7]) +#define PT_REGS_RC(x) ((x)->gpr[3]) +#define PT_REGS_SP(x) ((x)->sp) +#define PT_REGS_IP(x) ((x)->nip) #endif + +#ifdef __powerpc__ +#define BPF_KPROBE_READ_RET_IP(ip, ctx) { (ip) = (ctx)->link; } +#define BPF_KRETPROBE_READ_RET_IP(ip, ctx) BPF_KPROBE_READ_RET_IP(ip, ctx) +#else +#define BPF_KPROBE_READ_RET_IP(ip, ctx) \ + bpf_probe_read(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)) +#define BPF_KRETPROBE_READ_RET_IP(ip, ctx) \ + bpf_probe_read(&(ip), sizeof(ip), \ + (void *)(PT_REGS_FP(ctx) + sizeof(ip))) +#endif + #endif
diff --git a/samples/bpf/spintest_kern.c b/samples/bpf/spintest_kern.c
index 4b27619..ce0167d 100644
--- a/samples/bpf/spintest_kern.c
+++ b/samples/bpf/spintest_kern.c@@ -34,7 +34,7 @@ struct bpf_map_def SEC("maps") stackmap = { #define PROG(foo) \ int foo(struct pt_regs *ctx) \ { \ - long v = ctx->ip, *val; \ + long v = PT_REGS_IP(ctx), *val; \ \ val = bpf_map_lookup_elem(&my_map, &v); \ bpf_map_update_elem(&my_map, &v, &v, BPF_ANY); \
diff --git a/samples/bpf/tracex2_kern.c b/samples/bpf/tracex2_kern.c
index 09c1adc..6d6eefd 100644
--- a/samples/bpf/tracex2_kern.c
+++ b/samples/bpf/tracex2_kern.c@@ -27,10 +27,10 @@ int bpf_prog2(struct pt_regs *ctx) long init_val = 1; long *value; - /* x64/s390x specific: read ip of kfree_skb caller. + /* read ip of kfree_skb caller. * non-portable version of __builtin_return_address(0) */ - bpf_probe_read(&loc, sizeof(loc), (void *)PT_REGS_RET(ctx)); + BPF_KPROBE_READ_RET_IP(loc, ctx); value = bpf_map_lookup_elem(&my_map, &loc); if (value)
diff --git a/samples/bpf/tracex4_kern.c b/samples/bpf/tracex4_kern.c
index ac46714..6dd8e38 100644
--- a/samples/bpf/tracex4_kern.c
+++ b/samples/bpf/tracex4_kern.c@@ -40,7 +40,7 @@ int bpf_prog2(struct pt_regs *ctx) long ip = 0; /* get ip address of kmem_cache_alloc_node() caller */ - bpf_probe_read(&ip, sizeof(ip), (void *)(PT_REGS_FP(ctx) + sizeof(ip))); + BPF_KRETPROBE_READ_RET_IP(ip, ctx); struct pair v = { .val = bpf_ktime_get_ns(),
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2.7.4