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Commit a99855d1 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'ebpf-samples-cross-compile' 

Joel Fernandes says:

====================
Add cross-compilation support to eBPF samples

These patches fix issues seen when cross-compiling eBPF samples on arm64.
Compared to [1], I dropped the controversial inline-asm patch and exploring
other options to fix it. However these patches are a step in the right
direction and I look forward to getting them into -next and the merge window.

Changes since v3:
- just a repost with acks

[1] https://lkml.org/lkml/2017/8/7/417


====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents ae3e24fd 8bf2ac25

samples/bpf/Makefile

+6 −1
Original line number Diff line number Diff line
@@ -177,6 +177,11 @@ HOSTLOADLIBES_syscall_tp += -lelf 
LLC ?= llc

CLANG ?= clang



# Detect that we're cross compiling and use the cross compiler

ifdef CROSS_COMPILE

HOSTCC = $(CROSS_COMPILE)gcc

endif



# Trick to allow make to be run from this directory

all:

	$(MAKE) -C ../../ $(CURDIR)/
@@ -225,7 +230,7 @@ $(obj)/%.o: $(src)/%.c 
	$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) -I$(obj) \

		-I$(srctree)/tools/testing/selftests/bpf/ \

		-D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \

		-Wno-compare-distinct-pointer-types \

		-D__TARGET_ARCH_$(ARCH) -Wno-compare-distinct-pointer-types \

		-Wno-gnu-variable-sized-type-not-at-end \

		-Wno-address-of-packed-member -Wno-tautological-compare \

		-Wno-unknown-warning-option \

samples/bpf/README.rst

+10 −0
Original line number Diff line number Diff line
@@ -64,3 +64,13 @@ It is also possible to point make to the newly compiled 'llc' or 
'clang' command via redefining LLC or CLANG on the make command line::



 make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang



Cross compiling samples

-----------------------

In order to cross-compile, say for arm64 targets, export CROSS_COMPILE and ARCH

environment variables before calling make. This will direct make to build

samples for the cross target.



export ARCH=arm64

export CROSS_COMPILE="aarch64-linux-gnu-"

make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang

samples/bpf/map_perf_test_kern.c

+1 −1
Original line number Diff line number Diff line
@@ -266,7 +266,7 @@ int stress_hash_map_lookup(struct pt_regs *ctx) 
	return 0;

}



SEC("kprobe/sys_getpgrp")

SEC("kprobe/sys_getppid")

int stress_array_map_lookup(struct pt_regs *ctx)

{

	u32 key = 1, i;

samples/bpf/map_perf_test_user.c

+1 −1
Original line number Diff line number Diff line
@@ -282,7 +282,7 @@ static void test_array_lookup(int cpu) 


	start_time = time_get_ns();

	for (i = 0; i < max_cnt; i++)

		syscall(__NR_getpgrp, 0);

		syscall(__NR_getppid, 0);

	printf("%d:array_lookup %lld lookups per sec\n",

	       cpu, max_cnt * 1000000000ll * 64 / (time_get_ns() - start_time));

}

tools/testing/selftests/bpf/bpf_helpers.h

+49 −7
Original line number Diff line number Diff line
@@ -109,7 +109,47 @@ static int (*bpf_skb_under_cgroup)(void *ctx, void *map, int index) = 
static int (*bpf_skb_change_head)(void *, int len, int flags) =

	(void *) BPF_FUNC_skb_change_head;



/* Scan the ARCH passed in from ARCH env variable (see Makefile) */

#if defined(__TARGET_ARCH_x86)

	#define bpf_target_x86

	#define bpf_target_defined

#elif defined(__TARGET_ARCH_s930x)

	#define bpf_target_s930x

	#define bpf_target_defined

#elif defined(__TARGET_ARCH_arm64)

	#define bpf_target_arm64

	#define bpf_target_defined

#elif defined(__TARGET_ARCH_mips)

	#define bpf_target_mips

	#define bpf_target_defined

#elif defined(__TARGET_ARCH_powerpc)

	#define bpf_target_powerpc

	#define bpf_target_defined

#elif defined(__TARGET_ARCH_sparc)

	#define bpf_target_sparc

	#define bpf_target_defined

#else

	#undef bpf_target_defined

#endif



/* Fall back to what the compiler says */

#ifndef bpf_target_defined

#if defined(__x86_64__)

	#define bpf_target_x86

#elif defined(__s390x__)

	#define bpf_target_s930x

#elif defined(__aarch64__)

	#define bpf_target_arm64

#elif defined(__mips__)

	#define bpf_target_mips

#elif defined(__powerpc__)

	#define bpf_target_powerpc

#elif defined(__sparc__)

	#define bpf_target_sparc

#endif

#endif



#if defined(bpf_target_x86)



#define PT_REGS_PARM1(x) ((x)->di)

#define PT_REGS_PARM2(x) ((x)->si)
@@ -122,7 +162,7 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 
#define PT_REGS_SP(x) ((x)->sp)

#define PT_REGS_IP(x) ((x)->ip)



#elif defined(__s390x__)

#elif defined(bpf_target_s390x)



#define PT_REGS_PARM1(x) ((x)->gprs[2])

#define PT_REGS_PARM2(x) ((x)->gprs[3])
@@ -135,7 +175,7 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 
#define PT_REGS_SP(x) ((x)->gprs[15])

#define PT_REGS_IP(x) ((x)->psw.addr)



#elif defined(__aarch64__)

#elif defined(bpf_target_arm64)



#define PT_REGS_PARM1(x) ((x)->regs[0])

#define PT_REGS_PARM2(x) ((x)->regs[1])
@@ -148,7 +188,7 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 
#define PT_REGS_SP(x) ((x)->sp)

#define PT_REGS_IP(x) ((x)->pc)



#elif defined(__mips__)

#elif defined(bpf_target_mips)



#define PT_REGS_PARM1(x) ((x)->regs[4])

#define PT_REGS_PARM2(x) ((x)->regs[5])
@@ -161,7 +201,7 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 
#define PT_REGS_SP(x) ((x)->regs[29])

#define PT_REGS_IP(x) ((x)->cp0_epc)



#elif defined(__powerpc__)

#elif defined(bpf_target_powerpc)



#define PT_REGS_PARM1(x) ((x)->gpr[3])

#define PT_REGS_PARM2(x) ((x)->gpr[4])
@@ -172,7 +212,7 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 
#define PT_REGS_SP(x) ((x)->sp)

#define PT_REGS_IP(x) ((x)->nip)



#elif defined(__sparc__)

#elif defined(bpf_target_sparc)



#define PT_REGS_PARM1(x) ((x)->u_regs[UREG_I0])

#define PT_REGS_PARM2(x) ((x)->u_regs[UREG_I1])
@@ -182,6 +222,8 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 
#define PT_REGS_RET(x) ((x)->u_regs[UREG_I7])

#define PT_REGS_RC(x) ((x)->u_regs[UREG_I0])

#define PT_REGS_SP(x) ((x)->u_regs[UREG_FP])



/* Should this also be a bpf_target check for the sparc case? */

#if defined(__arch64__)

#define PT_REGS_IP(x) ((x)->tpc)

#else
@@ -190,10 +232,10 @@ static int (*bpf_skb_change_head)(void *, int len, int flags) = 


#endif



#ifdef __powerpc__

#ifdef bpf_target_powerpc

#define BPF_KPROBE_READ_RET_IP(ip, ctx)		({ (ip) = (ctx)->link; })

#define BPF_KRETPROBE_READ_RET_IP		BPF_KPROBE_READ_RET_IP

#elif defined(__sparc__)

#elif bpf_target_sparc

#define BPF_KPROBE_READ_RET_IP(ip, ctx)		({ (ip) = PT_REGS_RET(ctx); })

#define BPF_KRETPROBE_READ_RET_IP		BPF_KPROBE_READ_RET_IP

#else