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linux-7.2.3/arch/powerpc/net/Makefile

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+# SPDX-License-Identifier: GPL-2.0
+#
+# Arch-specific network modules
+#
+obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o bpf_jit_comp$(BITS).o
+
+ifdef CONFIG_PPC64
+obj-$(CONFIG_BPF_JIT) += bpf_timed_may_goto.o
+endif

linux-7.2.3/arch/powerpc/net/bpf_jit.h

@@ -0,0 +1,229 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * bpf_jit.h: BPF JIT compiler for PPC
+ *
+ * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
+ * 	     2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
+ */
+#ifndef _BPF_JIT_H
+#define _BPF_JIT_H
+
+#ifndef __ASSEMBLER__
+
+#include <asm/types.h>
+#include <asm/ppc-opcode.h>
+#include <linux/build_bug.h>
+
+#ifdef CONFIG_PPC64_ELF_ABI_V1
+#define FUNCTION_DESCR_SIZE	24
+#else
+#define FUNCTION_DESCR_SIZE	0
+#endif
+
+#define CTX_NIA(ctx) ((unsigned long)ctx->idx * 4)
+
+#define SZL			sizeof(unsigned long)
+#define BPF_INSN_SAFETY		64
+#define BPF_PPC_TAILCALL	8
+
+#define PLANT_INSTR(d, idx, instr)					      \
+	do { if (d) { (d)[idx] = instr; } idx++; } while (0)
+#define EMIT(instr)		PLANT_INSTR(image, ctx->idx, instr)
+
+/* Long jump; (unconditional 'branch') */
+#define PPC_JMP(dest)							      \
+	do {								      \
+		long offset = (long)(dest) - CTX_NIA(ctx);		      \
+		if ((dest) != 0 && !is_offset_in_branch_range(offset)) {		      \
+			pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);			\
+			return -ERANGE;					      \
+		}							      \
+		EMIT(PPC_RAW_BRANCH(offset));				      \
+	} while (0)
+
+/* "cond" here covers BO:BI fields. */
+#define PPC_BCC_SHORT(cond, dest)					      \
+	do {								      \
+		long offset = (long)(dest) - CTX_NIA(ctx);		      \
+		if ((dest) != 0 && !is_offset_in_cond_branch_range(offset)) {		      \
+			pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);		\
+			return -ERANGE;					      \
+		}							      \
+		EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc));					\
+	} while (0)
+
+/* When constant jump offset is known prior */
+#define PPC_BCC_CONST_SHORT(cond, offset)							\
+	do {											\
+		BUILD_BUG_ON(offset < -0x8000 || offset > 0x7fff || (offset & 0x3));		\
+		EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc));	\
+	} while (0)
+
+/*
+ * Sign-extended 32-bit immediate load
+ *
+ * If this is a dummy pass (!image), account for
+ * maximum possible instructions.
+ */
+#define PPC_LI32(d, i)		do {					      \
+	if (!image)							      \
+		ctx->idx += 2;						      \
+	else {								      \
+		if ((int)(uintptr_t)(i) >= -32768 &&			      \
+				(int)(uintptr_t)(i) < 32768)		      \
+			EMIT(PPC_RAW_LI(d, i));				      \
+		else {							      \
+			EMIT(PPC_RAW_LIS(d, IMM_H(i)));			      \
+			if (IMM_L(i))					      \
+				EMIT(PPC_RAW_ORI(d, d, IMM_L(i)));	      \
+		}							      \
+	} } while (0)
+
+#ifdef CONFIG_PPC64
+
+/* If dummy pass (!image), account for maximum possible instructions */
+#define PPC_LI64(d, i)		do {					      \
+	if (!image)							      \
+		ctx->idx += 5;						      \
+	else {								      \
+		if ((long)(i) >= -2147483648 &&				      \
+				(long)(i) < 2147483648)			      \
+			PPC_LI32(d, i);					      \
+		else {							      \
+			if (!((uintptr_t)(i) & 0xffff800000000000ULL))	      \
+				EMIT(PPC_RAW_LI(d, ((uintptr_t)(i) >> 32) &   \
+						0xffff));		      \
+			else {						      \
+				EMIT(PPC_RAW_LIS(d, ((uintptr_t)(i) >> 48))); \
+				if ((uintptr_t)(i) & 0x0000ffff00000000ULL)   \
+					EMIT(PPC_RAW_ORI(d, d,		      \
+					  ((uintptr_t)(i) >> 32) & 0xffff));  \
+			}						      \
+			EMIT(PPC_RAW_SLDI(d, d, 32));			      \
+			if ((uintptr_t)(i) & 0x00000000ffff0000ULL)	      \
+				EMIT(PPC_RAW_ORIS(d, d,			      \
+					 ((uintptr_t)(i) >> 16) & 0xffff));   \
+			if ((uintptr_t)(i) & 0x000000000000ffffULL)	      \
+				EMIT(PPC_RAW_ORI(d, d, (uintptr_t)(i) &       \
+							0xffff));             \
+		}							      \
+	} } while (0)
+#define PPC_LI_ADDR	PPC_LI64
+
+#ifndef CONFIG_PPC_KERNEL_PCREL
+#define PPC64_LOAD_PACA()						      \
+	EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc)))
+#else
+#define PPC64_LOAD_PACA()	do {} while (0)
+#endif
+#else
+#define PPC_LI64(d, i)	BUILD_BUG()
+#define PPC_LI_ADDR	PPC_LI32
+#define PPC64_LOAD_PACA() BUILD_BUG()
+#endif
+
+/*
+ * The fly in the ointment of code size changing from pass to pass is
+ * avoided by padding the short branch case with a NOP.	 If code size differs
+ * with different branch reaches we will have the issue of code moving from
+ * one pass to the next and will need a few passes to converge on a stable
+ * state.
+ */
+#define PPC_BCC(cond, dest)	do {					      \
+		if (is_offset_in_cond_branch_range((long)(dest) - CTX_NIA(ctx))) {	\
+			PPC_BCC_SHORT(cond, dest);			      \
+			EMIT(PPC_RAW_NOP());				      \
+		} else {						      \
+			/* Flip the 'T or F' bit to invert comparison */      \
+			PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, CTX_NIA(ctx) + 2*4);  \
+			PPC_JMP(dest);					      \
+		} } while(0)
+
+/* To create a branch condition, select a bit of cr0... */
+#define CR0_LT		0
+#define CR0_GT		1
+#define CR0_EQ		2
+/* ...and modify BO[3] */
+#define COND_CMP_TRUE	0x100
+#define COND_CMP_FALSE	0x000
+/* Together, they make all required comparisons: */
+#define COND_GT		(CR0_GT | COND_CMP_TRUE)
+#define COND_GE		(CR0_LT | COND_CMP_FALSE)
+#define COND_EQ		(CR0_EQ | COND_CMP_TRUE)
+#define COND_NE		(CR0_EQ | COND_CMP_FALSE)
+#define COND_LT		(CR0_LT | COND_CMP_TRUE)
+#define COND_LE		(CR0_GT | COND_CMP_FALSE)
+
+#define SEEN_FUNC	0x20000000 /* might call external helpers */
+#define SEEN_TAILCALL	0x40000000 /* uses tail calls */
+
+struct codegen_context {
+	/*
+	 * This is used to track register usage as well
+	 * as calls to external helpers.
+	 * - register usage is tracked with corresponding
+	 *   bits (r3-r31)
+	 * - rest of the bits can be used to track other
+	 *   things -- for now, we use bits 0 to 2
+	 *   encoded in SEEN_* macros above
+	 */
+	unsigned int seen;
+	unsigned int idx;
+	unsigned int stack_size;
+	int b2p[MAX_BPF_JIT_REG + 3];
+	unsigned int exentry_idx;
+	unsigned int alt_exit_addr;
+	u64 arena_vm_start;
+	u64 user_vm_start;
+	bool is_subprog;
+	bool exception_boundary;
+	bool exception_cb;
+	void __percpu *priv_sp;
+	unsigned int priv_stack_size;
+};
+
+/* Memory size & magic-value to detect private stack overflow/underflow */
+#define PRIV_STACK_GUARD_SZ    16
+#define PRIV_STACK_GUARD_VAL   0xEB9F12345678eb9fULL
+
+#define bpf_to_ppc(r)	(ctx->b2p[r])
+
+#ifdef CONFIG_PPC32
+#define BPF_FIXUP_LEN	3 /* Three instructions => 12 bytes */
+#else
+#define BPF_FIXUP_LEN	2 /* Two instructions => 8 bytes */
+#endif
+
+static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
+{
+	return ctx->seen & (1 << (31 - i));
+}
+
+static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
+{
+	ctx->seen |= 1 << (31 - i);
+}
+
+static inline void bpf_clear_seen_register(struct codegen_context *ctx, int i)
+{
+	ctx->seen &= ~(1 << (31 - i));
+}
+
+void bpf_jit_init_reg_mapping(struct codegen_context *ctx);
+int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func);
+int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
+		       u32 *addrs, int pass, bool extra_pass);
+void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx);
+void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx);
+void bpf_jit_build_fentry_stubs(u32 *image, struct codegen_context *ctx);
+void bpf_jit_realloc_regs(struct codegen_context *ctx);
+int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr);
+void prepare_for_fsession_fentry(u32 *image, struct codegen_context *ctx, int cookie_cnt,
+								int cookie_off, int retval_off);
+void store_func_meta(u32 *image, struct codegen_context *ctx, u64 func_meta, int func_meta_off);
+int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, int pass,
+			  struct codegen_context *ctx, int insn_idx,
+			  int jmp_off, int dst_reg, u32 code);
+#endif
+
+#endif

linux-7.2.3/arch/powerpc/net/bpf_timed_may_goto.S

@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2025 IBM Corporation, Saket Kumar Bhaskar <skb99@linux.ibm.com> */
+
+#include <linux/linkage.h>
+#include <asm/ppc_asm.h>
+
+/*
+ * arch_bpf_timed_may_goto() trampoline for powerpc64
+ *
+ * Custom BPF convention (verifier/JIT):
+ *	- input:  stack offset in BPF_REG_AX (r12)
+ *	- output: updated count in BPF_REG_AX (r12)
+ *
+ * Call bpf_check_timed_may_goto(ptr) with normal powerpc64 ABI:
+ * 	- r3 = ptr, return in r3
+ *
+ * Preserve BPF regs R0-R5 (mapping: r8, r3-r7).
+ */
+
+SYM_FUNC_START(arch_bpf_timed_may_goto)
+	/* Prologue: save LR, allocate frame */
+	mflr    r0
+	std     r0, 16(r1)
+	stdu    r1, -112(r1)
+
+	/* Save BPF registers R0 - R5 (r8, r3-r7) */
+	std     r3, 32(r1)
+	std     r4, 40(r1)
+	std     r5, 48(r1)
+	std     r6, 56(r1)
+	std     r7, 64(r1)
+	std     r8, 72(r1)
+
+	/*
+	 * r3 = BPF_REG_FP + BPF_REG_AX
+	 * BPF_REG_FP is r31; BPF_REG_AX is r12 (stack offset in bytes).
+	 */
+	add     r3, r31, r12
+	bl      bpf_check_timed_may_goto
+
+	/* Put return value back into AX */
+	mr      r12, r3
+
+	/* Restore BPF registers R0 - R5 (r8, r3-r7) */
+	ld      r3, 32(r1)
+	ld      r4, 40(r1)
+	ld      r5, 48(r1)
+	ld      r6, 56(r1)
+	ld      r7, 64(r1)
+	ld      r8, 72(r1)
+
+	/* Epilogue: pop frame, restore LR, return */
+	addi    r1, r1, 112
+	ld      r0, 16(r1)
+	mtlr    r0
+	blr
+SYM_FUNC_END(arch_bpf_timed_may_goto)