diff mbox series

[bpf-next,05/10] s390/bpf: Support BPF_PROBE_MEM32

Message ID 20240627090900.20017-6-iii@linux.ibm.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series s390/bpf: Implement arena | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-0 success Logs for Lint
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Unittests
bpf/vmtest-bpf-next-VM_Test-3 success Logs for Validate matrix.py
bpf/vmtest-bpf-next-VM_Test-5 success Logs for aarch64-gcc / build-release
bpf/vmtest-bpf-next-PR fail PR summary
bpf/vmtest-bpf-next-VM_Test-9 success Logs for s390x-gcc / build-release
bpf/vmtest-bpf-next-VM_Test-10 success Logs for s390x-gcc / test
bpf/vmtest-bpf-next-VM_Test-11 success Logs for s390x-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-12 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-13 fail Logs for x86_64-gcc / build / build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-4 fail Logs for aarch64-gcc / build / build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-7 success Logs for aarch64-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-8 fail Logs for s390x-gcc / build / build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-14 success Logs for x86_64-gcc / build-release
bpf/vmtest-bpf-next-VM_Test-15 success Logs for x86_64-gcc / test
bpf/vmtest-bpf-next-VM_Test-6 success Logs for aarch64-gcc / test
bpf/vmtest-bpf-next-VM_Test-16 success Logs for x86_64-gcc / veristat
bpf/vmtest-bpf-next-VM_Test-17 fail Logs for x86_64-llvm-17 / build / build for x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-18 fail Logs for x86_64-llvm-17 / build-release / build for x86_64 with llvm-17-O2
bpf/vmtest-bpf-next-VM_Test-19 success Logs for x86_64-llvm-17 / test
bpf/vmtest-bpf-next-VM_Test-20 success Logs for x86_64-llvm-17 / veristat
bpf/vmtest-bpf-next-VM_Test-21 fail Logs for x86_64-llvm-18 / build / build for x86_64 with llvm-18
bpf/vmtest-bpf-next-VM_Test-22 fail Logs for x86_64-llvm-18 / build-release / build for x86_64 with llvm-18-O2
bpf/vmtest-bpf-next-VM_Test-23 success Logs for x86_64-llvm-18 / test
bpf/vmtest-bpf-next-VM_Test-24 success Logs for x86_64-llvm-18 / veristat
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 12 maintainers not CCed: yonghong.song@linux.dev svens@linux.ibm.com haoluo@google.com linux-s390@vger.kernel.org jolsa@kernel.org song@kernel.org john.fastabend@gmail.com eddyz87@gmail.com kpsingh@kernel.org martin.lau@linux.dev sdf@google.com borntraeger@linux.ibm.com
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 263 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Ilya Leoshkevich June 27, 2024, 9:07 a.m. UTC 
BPF_PROBE_MEM32 is a new mode for LDX, ST and STX instructions. The JIT
is supposed to add the start address of the kernel arena mapping to the
%dst register, and use a probing variant of the respective memory
access.

Reuse the existing probing infrastructure for that. Put the arena
address into the literal pool, load it into %r1 and use that as an
index register. Do not clear any registers in ex_handler_bpf() for
failing ST and STX instructions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 arch/s390/net/bpf_jit_comp.c | 137 ++++++++++++++++++++++++++++-------
 1 file changed, 110 insertions(+), 27 deletions(-)
diff mbox series

Patch

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index ecd53f8f0602..4b62b5162dfb 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -53,6 +53,7 @@  struct bpf_jit {
 	int excnt;		/* Number of exception table entries */
 	int prologue_plt_ret;	/* Return address for prologue hotpatch PLT */
 	int prologue_plt;	/* Start of prologue hotpatch PLT */
+	int kern_arena;		/* Pool offset of kernel arena address */
 };
 
 #define SEEN_MEM	BIT(0)		/* use mem[] for temporary storage */
@@ -670,7 +671,8 @@  static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
 bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs)
 {
 	regs->psw.addr = extable_fixup(x);
-	regs->gprs[x->data] = 0;
+	if (x->data != -1)
+		regs->gprs[x->data] = 0;
 	return true;
 }
 
@@ -681,6 +683,7 @@  struct bpf_jit_probe {
 	int prg;	/* JITed instruction offset */
 	int nop_prg;	/* JITed nop offset */
 	int reg;	/* Register to clear on exception */
+	int arena_reg;	/* Register to use for arena addressing */
 };
 
 static void bpf_jit_probe_init(struct bpf_jit_probe *probe)
@@ -688,6 +691,7 @@  static void bpf_jit_probe_init(struct bpf_jit_probe *probe)
 	probe->prg = -1;
 	probe->nop_prg = -1;
 	probe->reg = -1;
+	probe->arena_reg = REG_0;
 }
 
 /*
@@ -708,13 +712,31 @@  static void bpf_jit_probe_load_pre(struct bpf_jit *jit, struct bpf_insn *insn,
 				   struct bpf_jit_probe *probe)
 {
 	if (BPF_MODE(insn->code) != BPF_PROBE_MEM &&
-	    BPF_MODE(insn->code) != BPF_PROBE_MEMSX)
+	    BPF_MODE(insn->code) != BPF_PROBE_MEMSX &&
+	    BPF_MODE(insn->code) != BPF_PROBE_MEM32)
 		return;
 
+	if (BPF_MODE(insn->code) == BPF_PROBE_MEM32) {
+		/* lgrl %r1,kern_arena */
+		EMIT6_PCREL_RILB(0xc4080000, REG_W1, jit->kern_arena);
+		probe->arena_reg = REG_W1;
+	}
 	probe->prg = jit->prg;
 	probe->reg = reg2hex[insn->dst_reg];
 }
 
+static void bpf_jit_probe_store_pre(struct bpf_jit *jit, struct bpf_insn *insn,
+				    struct bpf_jit_probe *probe)
+{
+	if (BPF_MODE(insn->code) != BPF_PROBE_MEM32)
+		return;
+
+	/* lgrl %r1,kern_arena */
+	EMIT6_PCREL_RILB(0xc4080000, REG_W1, jit->kern_arena);
+	probe->arena_reg = REG_W1;
+	probe->prg = jit->prg;
+}
+
 static int bpf_jit_probe_post(struct bpf_jit *jit, struct bpf_prog *fp,
 			      struct bpf_jit_probe *probe)
 {
@@ -1384,51 +1406,99 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 	 * BPF_ST(X)
 	 */
 	case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */
-		/* stcy %src,off(%dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off);
+	case BPF_STX | BPF_PROBE_MEM32 | BPF_B:
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* stcy %src,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
-		/* sthy %src,off(%dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off);
+	case BPF_STX | BPF_PROBE_MEM32 | BPF_H:
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* sthy %src,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
-		/* sty %src,off(%dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off);
+	case BPF_STX | BPF_PROBE_MEM32 | BPF_W:
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* sty %src,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
-		/* stg %src,off(%dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off);
+	case BPF_STX | BPF_PROBE_MEM32 | BPF_DW:
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* stg %src,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
+	case BPF_ST | BPF_PROBE_MEM32 | BPF_B:
 		/* lhi %w0,imm */
 		EMIT4_IMM(0xa7080000, REG_W0, (u8) imm);
-		/* stcy %w0,off(dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off);
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* stcy %w0,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
+	case BPF_ST | BPF_PROBE_MEM32 | BPF_H:
 		/* lhi %w0,imm */
 		EMIT4_IMM(0xa7080000, REG_W0, (u16) imm);
-		/* sthy %w0,off(dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off);
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* sthy %w0,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
+	case BPF_ST | BPF_PROBE_MEM32 | BPF_W:
 		/* llilf %w0,imm  */
 		EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm);
-		/* sty %w0,off(%dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off);
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* sty %w0,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
+	case BPF_ST | BPF_PROBE_MEM32 | BPF_DW:
 		/* lgfi %w0,imm */
 		EMIT6_IMM(0xc0010000, REG_W0, imm);
-		/* stg %w0,off(%dst) */
-		EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off);
+		bpf_jit_probe_store_pre(jit, insn, &probe);
+		/* stg %w0,off(%dst,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg,
+			      probe.arena_reg, off);
+		err = bpf_jit_probe_post(jit, fp, &probe);
+		if (err < 0)
+			return err;
 		jit->seen |= SEEN_MEM;
 		break;
 	/*
@@ -1506,9 +1576,11 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 	 */
 	case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
 	case BPF_LDX | BPF_PROBE_MEM | BPF_B:
+	case BPF_LDX | BPF_PROBE_MEM32 | BPF_B:
 		bpf_jit_probe_load_pre(jit, insn, &probe);
-		/* llgc %dst,0(off,%src) */
-		EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
+		/* llgc %dst,off(%src,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg,
+			      probe.arena_reg, off);
 		err = bpf_jit_probe_post(jit, fp, &probe);
 		if (err < 0)
 			return err;
@@ -1519,7 +1591,7 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 	case BPF_LDX | BPF_MEMSX | BPF_B: /* dst = *(s8 *)(ul) (src + off) */
 	case BPF_LDX | BPF_PROBE_MEMSX | BPF_B:
 		bpf_jit_probe_load_pre(jit, insn, &probe);
-		/* lgb %dst,0(off,%src) */
+		/* lgb %dst,off(%src) */
 		EMIT6_DISP_LH(0xe3000000, 0x0077, dst_reg, src_reg, REG_0, off);
 		err = bpf_jit_probe_post(jit, fp, &probe);
 		if (err < 0)
@@ -1528,9 +1600,11 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 		break;
 	case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
 	case BPF_LDX | BPF_PROBE_MEM | BPF_H:
+	case BPF_LDX | BPF_PROBE_MEM32 | BPF_H:
 		bpf_jit_probe_load_pre(jit, insn, &probe);
-		/* llgh %dst,0(off,%src) */
-		EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
+		/* llgh %dst,off(%src,%arena) */
+		EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg,
+			      probe.arena_reg, off);
 		err = bpf_jit_probe_post(jit, fp, &probe);
 		if (err < 0)
 			return err;
@@ -1541,7 +1615,7 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 	case BPF_LDX | BPF_MEMSX | BPF_H: /* dst = *(s16 *)(ul) (src + off) */
 	case BPF_LDX | BPF_PROBE_MEMSX | BPF_H:
 		bpf_jit_probe_load_pre(jit, insn, &probe);
-		/* lgh %dst,0(off,%src) */
+		/* lgh %dst,off(%src) */
 		EMIT6_DISP_LH(0xe3000000, 0x0015, dst_reg, src_reg, REG_0, off);
 		err = bpf_jit_probe_post(jit, fp, &probe);
 		if (err < 0)
@@ -1550,10 +1624,12 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 		break;
 	case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
 	case BPF_LDX | BPF_PROBE_MEM | BPF_W:
+	case BPF_LDX | BPF_PROBE_MEM32 | BPF_W:
 		bpf_jit_probe_load_pre(jit, insn, &probe);
 		/* llgf %dst,off(%src) */
 		jit->seen |= SEEN_MEM;
-		EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
+		EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg,
+			      probe.arena_reg, off);
 		err = bpf_jit_probe_post(jit, fp, &probe);
 		if (err < 0)
 			return err;
@@ -1572,10 +1648,12 @@  static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
 		break;
 	case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
 	case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
+	case BPF_LDX | BPF_PROBE_MEM32 | BPF_DW:
 		bpf_jit_probe_load_pre(jit, insn, &probe);
-		/* lg %dst,0(off,%src) */
+		/* lg %dst,off(%src,%arena) */
 		jit->seen |= SEEN_MEM;
-		EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off);
+		EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg,
+			      probe.arena_reg, off);
 		err = bpf_jit_probe_post(jit, fp, &probe);
 		if (err < 0)
 			return err;
@@ -1988,12 +2066,17 @@  static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp,
 			bool extra_pass, u32 stack_depth)
 {
 	int i, insn_count, lit32_size, lit64_size;
+	u64 kern_arena;
 
 	jit->lit32 = jit->lit32_start;
 	jit->lit64 = jit->lit64_start;
 	jit->prg = 0;
 	jit->excnt = 0;
 
+	kern_arena = bpf_arena_get_kern_vm_start(fp->aux->arena);
+	if (kern_arena)
+		jit->kern_arena = _EMIT_CONST_U64(kern_arena);
+
 	bpf_jit_prologue(jit, fp, stack_depth);
 	if (bpf_set_addr(jit, 0) < 0)
 		return -1;