Merge branch 'bpf-MIPS-infra'

David Daney says:

====================
bpf: Changes needed (or desired) for MIPS support

This is a grab bag of changes to the bpf testing infrastructure I
developed working on MIPS eBPF JIT support.  The change to
bpf_jit_disasm is probably universally beneficial, the others are more
MIPS specific.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

lib/test_bpf.c

@@ -435,6 +435,30 @@ static int bpf_fill_ld_abs_vlan_push_pop(struct bpf_test *self)
 	return 0;
 }
 
+static int bpf_fill_jump_around_ld_abs(struct bpf_test *self)
+{
+	unsigned int len = BPF_MAXINSNS;
+	struct bpf_insn *insn;
+	int i = 0;
+
+	insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);
+	if (!insn)
+		return -ENOMEM;
+
+	insn[i++] = BPF_MOV64_REG(R6, R1);
+	insn[i++] = BPF_LD_ABS(BPF_B, 0);
+	insn[i] = BPF_JMP_IMM(BPF_JEQ, R0, 10, len - i - 2);
+	i++;
+	while (i < len - 1)
+		insn[i++] = BPF_LD_ABS(BPF_B, 1);
+	insn[i] = BPF_EXIT_INSN();
+
+	self->u.ptr.insns = insn;
+	self->u.ptr.len = len;
+
+	return 0;
+}
+
 static int __bpf_fill_stxdw(struct bpf_test *self, int size)
 {
 	unsigned int len = BPF_MAXINSNS;
@@ -5044,6 +5068,14 @@ static struct bpf_test tests[] = {
 		{ { ETH_HLEN, 0xbef } },
 		.fill_helper = bpf_fill_ld_abs_vlan_push_pop,
 	},
+	{
+		"BPF_MAXINSNS: jump around ld_abs",
+		{ },
+		INTERNAL,
+		{ 10, 11 },
+		{ { 2, 10 } },
+		.fill_helper = bpf_fill_jump_around_ld_abs,
+	},
 	/*
 	 * LD_IND / LD_ABS on fragmented SKBs
 	 */

samples/bpf/Makefile

@@ -160,6 +160,17 @@ clean:
 	$(MAKE) -C ../../ M=$(CURDIR) clean
 	@rm -f *~
 
+$(obj)/syscall_nrs.s:	$(src)/syscall_nrs.c
+	$(call if_changed_dep,cc_s_c)
+
+$(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
+	$(call filechk,offsets,__SYSCALL_NRS_H__)
+
+clean-files += syscall_nrs.h
+
+FORCE:
+
+
 # Verify LLVM compiler tools are available and bpf target is supported by llc
 .PHONY: verify_cmds verify_target_bpf $(CLANG) $(LLC)
 
@@ -180,6 +191,8 @@ verify_target_bpf: verify_cmds
 
 $(src)/*.c: verify_target_bpf
 
+$(obj)/tracex5_kern.o: $(obj)/syscall_nrs.h
+
 # asm/sysreg.h - inline assembly used by it is incompatible with llvm.
 # But, there is no easy way to fix it, so just exclude it since it is
 # useless for BPF samples.

samples/bpf/bpf_helpers.h

@@ -136,6 +136,19 @@ 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__)
+
+#define PT_REGS_PARM1(x) ((x)->regs[4])
+#define PT_REGS_PARM2(x) ((x)->regs[5])
+#define PT_REGS_PARM3(x) ((x)->regs[6])
+#define PT_REGS_PARM4(x) ((x)->regs[7])
+#define PT_REGS_PARM5(x) ((x)->regs[8])
+#define PT_REGS_RET(x) ((x)->regs[31])
+#define PT_REGS_FP(x) ((x)->regs[30]) /* Works only with CONFIG_FRAME_POINTER */
+#define PT_REGS_RC(x) ((x)->regs[1])
+#define PT_REGS_SP(x) ((x)->regs[29])
+#define PT_REGS_IP(x) ((x)->cp0_epc)
+
 #elif defined(__powerpc__)
 
 #define PT_REGS_PARM1(x) ((x)->gpr[3])

samples/bpf/syscall_nrs.c

+#include <uapi/linux/unistd.h>
+#include <linux/kbuild.h>
+
+#define SYSNR(_NR) DEFINE(SYS ## _NR, _NR)
+
+void syscall_defines(void)
+{
+	COMMENT("Linux system call numbers.");
+	SYSNR(__NR_write);
+	SYSNR(__NR_read);
+	SYSNR(__NR_mmap);
+}

samples/bpf/tracex5_kern.c

@@ -9,6 +9,7 @@
 #include <uapi/linux/bpf.h>
 #include <uapi/linux/seccomp.h>
 #include <uapi/linux/unistd.h>
+#include "syscall_nrs.h"
 #include "bpf_helpers.h"
 
 #define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F
@@ -17,7 +18,11 @@ struct bpf_map_def SEC("maps") progs = {
 	.type = BPF_MAP_TYPE_PROG_ARRAY,
 	.key_size = sizeof(u32),
 	.value_size = sizeof(u32),
+#ifdef __mips__
+	.max_entries = 6000, /* MIPS n64 syscalls start at 5000 */
+#else
 	.max_entries = 1024,
+#endif
 };
 
 SEC("kprobe/__seccomp_filter")
@@ -37,7 +42,7 @@ int bpf_prog1(struct pt_regs *ctx)
 }
 
 /* we jump here when syscall number == __NR_write */
-PROG(__NR_write)(struct pt_regs *ctx)
+PROG(SYS__NR_write)(struct pt_regs *ctx)
 {
 	struct seccomp_data sd;
 
@@ -50,7 +55,7 @@ PROG(__NR_write)(struct pt_regs *ctx)
 	return 0;
 }
 
-PROG(__NR_read)(struct pt_regs *ctx)
+PROG(SYS__NR_read)(struct pt_regs *ctx)
 {
 	struct seccomp_data sd;
 
@@ -63,7 +68,7 @@ PROG(__NR_read)(struct pt_regs *ctx)
 	return 0;
 }
 
-PROG(__NR_mmap)(struct pt_regs *ctx)
+PROG(SYS__NR_mmap)(struct pt_regs *ctx)
 {
 	char fmt[] = "mmap\n";
 	bpf_trace_printk(fmt, sizeof(fmt));

tools/net/bpf_jit_disasm.c

@@ -159,8 +159,8 @@ static void put_log_buff(char *buff)
 	free(buff);
 }
 
-static unsigned int get_last_jit_image(char *haystack, size_t hlen,
-				       uint8_t *image, size_t ilen)
+static uint8_t *get_last_jit_image(char *haystack, size_t hlen,
+				   unsigned int *ilen)
 {
 	char *ptr, *pptr, *tmp;
 	off_t off = 0;
@@ -168,9 +168,10 @@ static unsigned int get_last_jit_image(char *haystack, size_t hlen,
 	regmatch_t pmatch[1];
 	unsigned long base;
 	regex_t regex;
+	uint8_t *image;
 
 	if (hlen == 0)
-		return 0;
+		return NULL;
 
 	ret = regcomp(&regex, "flen=[[:alnum:]]+ proglen=[[:digit:]]+ "
 		      "pass=[[:digit:]]+ image=[[:xdigit:]]+", REG_EXTENDED);
@@ -194,11 +195,22 @@ static unsigned int get_last_jit_image(char *haystack, size_t hlen,
 		     &flen, &proglen, &pass, &base);
 	if (ret != 4) {
 		regfree(&regex);
-		return 0;
+		return NULL;
+	}
+	if (proglen > 1000000) {
+		printf("proglen of %d too big, stopping\n", proglen);
+		return NULL;
 	}
 
+	image = malloc(proglen);
+	if (!image) {
+		printf("Out of memory\n");
+		return NULL;
+	}
+	memset(image, 0, proglen);
+
 	tmp = ptr = haystack + off;
-	while ((ptr = strtok(tmp, "\n")) != NULL && ulen < ilen) {
+	while ((ptr = strtok(tmp, "\n")) != NULL && ulen < proglen) {
 		tmp = NULL;
 		if (!strstr(ptr, "JIT code"))
 			continue;
@@ -208,10 +220,12 @@ static unsigned int get_last_jit_image(char *haystack, size_t hlen,
 		ptr = pptr;
 		do {
 			image[ulen++] = (uint8_t) strtoul(pptr, &pptr, 16);
-			if (ptr == pptr || ulen >= ilen) {
+			if (ptr == pptr) {
 				ulen--;
 				break;
 			}
+			if (ulen >= proglen)
+				break;
 			ptr = pptr;
 		} while (1);
 	}
@@ -222,7 +236,8 @@ static unsigned int get_last_jit_image(char *haystack, size_t hlen,
 	printf("%lx + <x>:\n", base);
 
 	regfree(&regex);
-	return ulen;
+	*ilen = ulen;
+	return image;
 }
 
 static void usage(void)
@@ -237,12 +252,12 @@ static void usage(void)
 int main(int argc, char **argv)
 {
 	unsigned int len, klen, opt, opcodes = 0;
-	static uint8_t image[32768];
 	char *kbuff, *file = NULL;
 	char *ofile = NULL;
 	int ofd;
 	ssize_t nr;
 	uint8_t *pos;
+	uint8_t *image = NULL;
 
 	while ((opt = getopt(argc, argv, "of:O:")) != -1) {
 		switch (opt) {
@@ -262,7 +277,6 @@ int main(int argc, char **argv)
 	}
 
 	bfd_init();
-	memset(image, 0, sizeof(image));
 
 	kbuff = get_log_buff(file, &klen);
 	if (!kbuff) {
@@ -270,8 +284,8 @@ int main(int argc, char **argv)
 		return -1;
 	}
 
-	len = get_last_jit_image(kbuff, klen, image, sizeof(image));
-	if (len <= 0) {
+	image = get_last_jit_image(kbuff, klen, &len);
+	if (!image) {
 		fprintf(stderr, "No JIT image found!\n");
 		goto done;
 	}
@@ -301,5 +315,6 @@ int main(int argc, char **argv)
 
 done:
 	put_log_buff(kbuff);
+	free(image);
 	return 0;
 }