File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/powerpc/net/bpf_jit_asm.S b/arch/powerpc/net/bpf_jit_asm.S
new file mode 100644
index 0000000..8ff5a3b
--- /dev/null
+++ b/arch/powerpc/net/bpf_jit_asm.S
@@ -0,0 +1,229 @@
+/* bpf_jit.S: Packet/header access helper functions
+ * for PPC64 BPF compiler.
+ *
+ * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <asm/ppc_asm.h>
+#include "bpf_jit.h"
+
+/*
+ * All of these routines are called directly from generated code,
+ * whose register usage is:
+ *
+ * r3 skb
+ * r4,r5 A,X
+ * r6 *** address parameter to helper ***
+ * r7-r10 scratch
+ * r14 skb->data
+ * r15 skb headlen
+ * r16-31 M[]
+ */
+
+/*
+ * To consider: These helpers are so small it could be better to just
+ * generate them inline. Inline code can do the simple headlen check
+ * then branch directly to slow_path_XXX if required. (In fact, could
+ * load a spare GPR with the address of slow_path_generic and pass size
+ * as an argument, making the call site a mtlr, li and bllr.)
+ */
+ .globl sk_load_word
+sk_load_word:
+ PPC_LCMPI r_addr, 0
+ blt bpf_slow_path_word_neg
+ .globl sk_load_word_positive_offset
+sk_load_word_positive_offset:
+ /* Are we accessing past headlen? */
+ subi r_scratch1, r_HL, 4
+ PPC_LCMP r_scratch1, r_addr
+ blt bpf_slow_path_word
+ /* Nope, just hitting the header. cr0 here is eq or gt! */
+#ifdef __LITTLE_ENDIAN__
+ lwbrx r_A, r_D, r_addr
+#else
+ lwzx r_A, r_D, r_addr
+#endif
+ blr /* Return success, cr0 != LT */
+
+ .globl sk_load_half
+sk_load_half:
+ PPC_LCMPI r_addr, 0
+ blt bpf_slow_path_half_neg
+ .globl sk_load_half_positive_offset
+sk_load_half_positive_offset:
+ subi r_scratch1, r_HL, 2
+ PPC_LCMP r_scratch1, r_addr
+ blt bpf_slow_path_half
+#ifdef __LITTLE_ENDIAN__
+ lhbrx r_A, r_D, r_addr
+#else
+ lhzx r_A, r_D, r_addr
+#endif
+ blr
+
+ .globl sk_load_byte
+sk_load_byte:
+ PPC_LCMPI r_addr, 0
+ blt bpf_slow_path_byte_neg
+ .globl sk_load_byte_positive_offset
+sk_load_byte_positive_offset:
+ PPC_LCMP r_HL, r_addr
+ ble bpf_slow_path_byte
+ lbzx r_A, r_D, r_addr
+ blr
+
+/*
+ * BPF_LDX | BPF_B | BPF_MSH: ldxb 4*([offset]&0xf)
+ * r_addr is the offset value
+ */
+ .globl sk_load_byte_msh
+sk_load_byte_msh:
+ PPC_LCMPI r_addr, 0
+ blt bpf_slow_path_byte_msh_neg
+ .globl sk_load_byte_msh_positive_offset
+sk_load_byte_msh_positive_offset:
+ PPC_LCMP r_HL, r_addr
+ ble bpf_slow_path_byte_msh
+ lbzx r_X, r_D, r_addr
+ rlwinm r_X, r_X, 2, 32-4-2, 31-2
+ blr
+
+/* Call out to skb_copy_bits:
+ * We'll need to back up our volatile regs first; we have
+ * local variable space at r1+(BPF_PPC_STACK_BASIC).
+ * Allocate a new stack frame here to remain ABI-compliant in
+ * stashing LR.
+ */
+#define bpf_slow_path_common(SIZE) \
+ mflr r0; \
+ PPC_STL r0, PPC_LR_STKOFF(r1); \
+ /* R3 goes in parameter space of caller's frame */ \
+ PPC_STL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
+ PPC_STL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
+ PPC_STL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
+ addi r5, r1, BPF_PPC_STACK_BASIC+(2*REG_SZ); \
+ PPC_STLU r1, -BPF_PPC_SLOWPATH_FRAME(r1); \
+ /* R3 = r_skb, as passed */ \
+ mr r4, r_addr; \
+ li r6, SIZE; \
+ bl skb_copy_bits; \
+ nop; \
+ /* R3 = 0 on success */ \
+ addi r1, r1, BPF_PPC_SLOWPATH_FRAME; \
+ PPC_LL r0, PPC_LR_STKOFF(r1); \
+ PPC_LL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
+ PPC_LL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
+ mtlr r0; \
+ PPC_LCMPI r3, 0; \
+ blt bpf_error; /* cr0 = LT */ \
+ PPC_LL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
+ /* Great success! */
+
+bpf_slow_path_word:
+ bpf_slow_path_common(4)
+ /* Data value is on stack, and cr0 != LT */
+ lwz r_A, BPF_PPC_STACK_BASIC+(2*REG_SZ)(r1)
+ blr
+
+bpf_slow_path_half:
+ bpf_slow_path_common(2)
+ lhz r_A, BPF_PPC_STACK_BASIC+(2*8)(r1)
+ blr
+
+bpf_slow_path_byte:
+ bpf_slow_path_common(1)
+ lbz r_A, BPF_PPC_STACK_BASIC+(2*8)(r1)
+ blr
+
+bpf_slow_path_byte_msh:
+ bpf_slow_path_common(1)
+ lbz r_X, BPF_PPC_STACK_BASIC+(2*8)(r1)
+ rlwinm r_X, r_X, 2, 32-4-2, 31-2
+ blr
+
+/* Call out to bpf_internal_load_pointer_neg_helper:
+ * We'll need to back up our volatile regs first; we have
+ * local variable space at r1+(BPF_PPC_STACK_BASIC).
+ * Allocate a new stack frame here to remain ABI-compliant in
+ * stashing LR.
+ */
+#define sk_negative_common(SIZE) \
+ mflr r0; \
+ PPC_STL r0, PPC_LR_STKOFF(r1); \
+ /* R3 goes in parameter space of caller's frame */ \
+ PPC_STL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
+ PPC_STL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
+ PPC_STL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
+ PPC_STLU r1, -BPF_PPC_SLOWPATH_FRAME(r1); \
+ /* R3 = r_skb, as passed */ \
+ mr r4, r_addr; \
+ li r5, SIZE; \
+ bl bpf_internal_load_pointer_neg_helper; \
+ nop; \
+ /* R3 != 0 on success */ \
+ addi r1, r1, BPF_PPC_SLOWPATH_FRAME; \
+ PPC_LL r0, PPC_LR_STKOFF(r1); \
+ PPC_LL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
+ PPC_LL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
+ mtlr r0; \
+ PPC_LCMPLI r3, 0; \
+ beq bpf_error_slow; /* cr0 = EQ */ \
+ mr r_addr, r3; \
+ PPC_LL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
+ /* Great success! */
+
+bpf_slow_path_word_neg:
+ lis r_scratch1,-32 /* SKF_LL_OFF */
+ PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
+ blt bpf_error /* cr0 = LT */
+ .globl sk_load_word_negative_offset
+sk_load_word_negative_offset:
+ sk_negative_common(4)
+ lwz r_A, 0(r_addr)
+ blr
+
+bpf_slow_path_half_neg:
+ lis r_scratch1,-32 /* SKF_LL_OFF */
+ PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
+ blt bpf_error /* cr0 = LT */
+ .globl sk_load_half_negative_offset
+sk_load_half_negative_offset:
+ sk_negative_common(2)
+ lhz r_A, 0(r_addr)
+ blr
+
+bpf_slow_path_byte_neg:
+ lis r_scratch1,-32 /* SKF_LL_OFF */
+ PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
+ blt bpf_error /* cr0 = LT */
+ .globl sk_load_byte_negative_offset
+sk_load_byte_negative_offset:
+ sk_negative_common(1)
+ lbz r_A, 0(r_addr)
+ blr
+
+bpf_slow_path_byte_msh_neg:
+ lis r_scratch1,-32 /* SKF_LL_OFF */
+ PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
+ blt bpf_error /* cr0 = LT */
+ .globl sk_load_byte_msh_negative_offset
+sk_load_byte_msh_negative_offset:
+ sk_negative_common(1)
+ lbz r_X, 0(r_addr)
+ rlwinm r_X, r_X, 2, 32-4-2, 31-2
+ blr
+
+bpf_error_slow:
+ /* fabricate a cr0 = lt */
+ li r_scratch1, -1
+ PPC_LCMPI r_scratch1, 0
+bpf_error:
+ /* Entered with cr0 = lt */
+ li r3, 0
+ /* Generated code will 'blt epilogue', returning 0. */
+ blr