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From: Ilya Leoshkevich <iii@linux.ibm.com>
To: bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: ys114321@gmail.com, daniel@iogearbox.net, sdf@fomichev.me,
	davem@davemloft.net, ast@kernel.org,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH v4 bpf-next 3/4] selftests/bpf: make PT_REGS_* work in userspace
Date: Thu, 11 Jul 2019 16:29:29 +0200	[thread overview]
Message-ID: <20190711142930.68809-4-iii@linux.ibm.com> (raw)
In-Reply-To: <20190711142930.68809-1-iii@linux.ibm.com>

Right now, on certain architectures, these macros are usable only with
kernel headers. This patch makes it possible to use them with userspace
headers and, as a consequence, not only in BPF samples, but also in BPF
selftests.

On s390, provide the forward declaration of struct pt_regs and cast it
to user_pt_regs in PT_REGS_* macros. This is necessary, because instead
of the full struct pt_regs, s390 exposes only its first member
user_pt_regs to userspace, and bpf_helpers.h is used with both userspace
(in selftests) and kernel (in samples) headers. It was added in commit
466698e654e8 ("s390/bpf: correct broken uapi for
BPF_PROG_TYPE_PERF_EVENT program type").

Ditto on arm64.

On x86, provide userspace versions of PT_REGS_* macros. Unlike s390 and
arm64, x86 provides struct pt_regs to both userspace and kernel, however,
with different member names.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tools/testing/selftests/bpf/bpf_helpers.h | 75 +++++++++++++++++------
 1 file changed, 55 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 73071a94769a..27090d94afb6 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -358,6 +358,7 @@ static int (*bpf_skb_adjust_room)(void *ctx, __s32 len_diff, __u32 mode,
 
 #if defined(bpf_target_x86)
 
+#ifdef __KERNEL__
 #define PT_REGS_PARM1(x) ((x)->di)
 #define PT_REGS_PARM2(x) ((x)->si)
 #define PT_REGS_PARM3(x) ((x)->dx)
@@ -368,19 +369,49 @@ static int (*bpf_skb_adjust_room)(void *ctx, __s32 len_diff, __u32 mode,
 #define PT_REGS_RC(x) ((x)->ax)
 #define PT_REGS_SP(x) ((x)->sp)
 #define PT_REGS_IP(x) ((x)->ip)
+#else
+#ifdef __i386__
+/* i386 kernel is built with -mregparm=3 */
+#define PT_REGS_PARM1(x) ((x)->eax)
+#define PT_REGS_PARM2(x) ((x)->edx)
+#define PT_REGS_PARM3(x) ((x)->ecx)
+#define PT_REGS_PARM4(x) 0
+#define PT_REGS_PARM5(x) 0
+#define PT_REGS_RET(x) ((x)->esp)
+#define PT_REGS_FP(x) ((x)->ebp)
+#define PT_REGS_RC(x) ((x)->eax)
+#define PT_REGS_SP(x) ((x)->esp)
+#define PT_REGS_IP(x) ((x)->eip)
+#else
+#define PT_REGS_PARM1(x) ((x)->rdi)
+#define PT_REGS_PARM2(x) ((x)->rsi)
+#define PT_REGS_PARM3(x) ((x)->rdx)
+#define PT_REGS_PARM4(x) ((x)->rcx)
+#define PT_REGS_PARM5(x) ((x)->r8)
+#define PT_REGS_RET(x) ((x)->rsp)
+#define PT_REGS_FP(x) ((x)->rbp)
+#define PT_REGS_RC(x) ((x)->rax)
+#define PT_REGS_SP(x) ((x)->rsp)
+#define PT_REGS_IP(x) ((x)->rip)
+#endif
+#endif
 
 #elif defined(bpf_target_s390)
 
-#define PT_REGS_PARM1(x) ((x)->gprs[2])
-#define PT_REGS_PARM2(x) ((x)->gprs[3])
-#define PT_REGS_PARM3(x) ((x)->gprs[4])
-#define PT_REGS_PARM4(x) ((x)->gprs[5])
-#define PT_REGS_PARM5(x) ((x)->gprs[6])
-#define PT_REGS_RET(x) ((x)->gprs[14])
-#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)->psw.addr)
+/* s390 provides user_pt_regs instead of struct pt_regs to userspace */
+struct pt_regs;
+#define PT_REGS_S390 const volatile user_pt_regs
+#define PT_REGS_PARM1(x) (((PT_REGS_S390 *)(x))->gprs[2])
+#define PT_REGS_PARM2(x) (((PT_REGS_S390 *)(x))->gprs[3])
+#define PT_REGS_PARM3(x) (((PT_REGS_S390 *)(x))->gprs[4])
+#define PT_REGS_PARM4(x) (((PT_REGS_S390 *)(x))->gprs[5])
+#define PT_REGS_PARM5(x) (((PT_REGS_S390 *)(x))->gprs[6])
+#define PT_REGS_RET(x) (((PT_REGS_S390 *)(x))->gprs[14])
+/* Works only with CONFIG_FRAME_POINTER */
+#define PT_REGS_FP(x) (((PT_REGS_S390 *)(x))->gprs[11])
+#define PT_REGS_RC(x) (((PT_REGS_S390 *)(x))->gprs[2])
+#define PT_REGS_SP(x) (((PT_REGS_S390 *)(x))->gprs[15])
+#define PT_REGS_IP(x) (((PT_REGS_S390 *)(x))->psw.addr)
 
 #elif defined(bpf_target_arm)
 
@@ -397,16 +428,20 @@ static int (*bpf_skb_adjust_room)(void *ctx, __s32 len_diff, __u32 mode,
 
 #elif defined(bpf_target_arm64)
 
-#define PT_REGS_PARM1(x) ((x)->regs[0])
-#define PT_REGS_PARM2(x) ((x)->regs[1])
-#define PT_REGS_PARM3(x) ((x)->regs[2])
-#define PT_REGS_PARM4(x) ((x)->regs[3])
-#define PT_REGS_PARM5(x) ((x)->regs[4])
-#define PT_REGS_RET(x) ((x)->regs[30])
-#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)
+/* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */
+struct pt_regs;
+#define PT_REGS_ARM64 const volatile struct user_pt_regs
+#define PT_REGS_PARM1(x) (((PT_REGS_ARM64 *)(x))->regs[0])
+#define PT_REGS_PARM2(x) (((PT_REGS_ARM64 *)(x))->regs[1])
+#define PT_REGS_PARM3(x) (((PT_REGS_ARM64 *)(x))->regs[2])
+#define PT_REGS_PARM4(x) (((PT_REGS_ARM64 *)(x))->regs[3])
+#define PT_REGS_PARM5(x) (((PT_REGS_ARM64 *)(x))->regs[4])
+#define PT_REGS_RET(x) (((PT_REGS_ARM64 *)(x))->regs[30])
+/* Works only with CONFIG_FRAME_POINTER */
+#define PT_REGS_FP(x) (((PT_REGS_ARM64 *)(x))->regs[29])
+#define PT_REGS_RC(x) (((PT_REGS_ARM64 *)(x))->regs[0])
+#define PT_REGS_SP(x) (((PT_REGS_ARM64 *)(x))->sp)
+#define PT_REGS_IP(x) (((PT_REGS_ARM64 *)(x))->pc)
 
 #elif defined(bpf_target_mips)
 
-- 
2.21.0


  parent reply	other threads:[~2019-07-11 14:31 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-11 14:29 [PATCH v4 bpf-next 0/4] selftests/bpf: fix compiling loop{1,2,3}.c on s390 Ilya Leoshkevich
2019-07-11 14:29 ` [PATCH v4 bpf-next 1/4] selftests/bpf: compile progs with -D__TARGET_ARCH_$(SRCARCH) Ilya Leoshkevich
2019-07-12  0:53   ` Andrii Nakryiko
2019-07-12  8:59     ` Ilya Leoshkevich
2019-07-12 17:28       ` Andrii Nakryiko
2019-07-11 14:29 ` [PATCH v4 bpf-next 2/4] selftests/bpf: fix s930 -> s390 typo Ilya Leoshkevich
2019-07-12  0:50   ` Andrii Nakryiko
2019-07-11 14:29 ` Ilya Leoshkevich [this message]
2019-07-12  0:49   ` [PATCH v4 bpf-next 3/4] selftests/bpf: make PT_REGS_* work in userspace Andrii Nakryiko
2019-07-11 14:29 ` [PATCH v4 bpf-next 4/4] selftests/bpf: fix compiling loop{1,2,3}.c on s390 Ilya Leoshkevich
2019-07-11 20:35 ` [PATCH v4 bpf-next 0/4] " Stanislav Fomichev
2019-07-12  8:55   ` Ilya Leoshkevich
2019-07-12 13:44     ` Daniel Borkmann

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