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samples/bpf: Enable powerpc support 

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.

Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Naveen N. Rao 2016-04-04 22:31:34 +05:30 committed by David S. Miller
parent 128d1514be
commit 138d6153a1
4 changed files with 30 additions and 4 deletions
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26
samples/bpf/bpf_helpers.h
View File

@ -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 BPF_KPROBE_READ_RET_IP
#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

2
samples/bpf/spintest_kern.c
View File

@ -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); \

4
samples/bpf/tracex2_kern.c
View File

@ -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)

2
samples/bpf/tracex4_kern.c
View File

@ -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(),