[PATCH 8/9] x86/bpf: Convert asm comments to AT&T syntax
From: Josh Poimboeuf
Date: Thu Jun 13 2019 - 11:20:34 EST
Convert the BPF JIT assembly comments to AT&T syntax to reduce
confusion. AT&T syntax is the default standard, used throughout Linux
and by the GNU assembler.
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/net/bpf_jit_comp.c | 156 ++++++++++++++++++------------------
1 file changed, 78 insertions(+), 78 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index bb1968fea50a..a92c2445441d 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -58,7 +58,7 @@ static bool is_uimm32(u64 value)
return value == (u64)(u32)value;
}
-/* mov dst, src */
+/* mov src, dst */
#define EMIT_mov(DST, SRC) \
do { \
if (DST != SRC) \
@@ -202,21 +202,21 @@ static void emit_prologue(u8 **pprog, u32 stack_depth)
u8 *prog = *pprog;
int cnt = 0;
- /* push rbp */
+ /* push %rbp */
EMIT1(0x55);
- /* mov rbp, rsp */
+ /* mov %rsp, %rbp */
EMIT3(0x48, 0x89, 0xE5);
- /* push r15 */
+ /* push %r15 */
EMIT2(0x41, 0x57);
- /* push r14 */
+ /* push %r14 */
EMIT2(0x41, 0x56);
- /* push r13 */
+ /* push %r13 */
EMIT2(0x41, 0x55);
- /* push r12 */
+ /* push %r12 */
EMIT2(0x41, 0x54);
- /* push rbx */
+ /* push %rbx */
EMIT1(0x53);
/*
@@ -231,11 +231,11 @@ static void emit_prologue(u8 **pprog, u32 stack_depth)
* R12 is used for the BPF program's FP register. It points to the end
* of the program's stack area.
*
- * mov r12, rsp
+ * mov %rsp, %r12
*/
EMIT3(0x49, 0x89, 0xE4);
- /* sub rsp, rounded_stack_depth */
+ /* sub rounded_stack_depth, %rsp */
EMIT3_off32(0x48, 0x81, 0xEC, round_up(stack_depth, 8));
BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
@@ -248,20 +248,20 @@ static void emit_epilogue(u8 **pprog)
u8 *prog = *pprog;
int cnt = 0;
- /* lea rsp, [rbp-0x28] */
+ /* lea -0x28(%rbp), %rsp */
EMIT4(0x48, 0x8D, 0x65, 0xD8);
- /* pop rbx */
+ /* pop %rbx */
EMIT1(0x5B);
- /* pop r12 */
+ /* pop %r12 */
EMIT2(0x41, 0x5C);
- /* pop r13 */
+ /* pop %r13 */
EMIT2(0x41, 0x5D);
- /* pop r14 */
+ /* pop %r14 */
EMIT2(0x41, 0x5E);
- /* pop r15 */
+ /* pop %r15 */
EMIT2(0x41, 0x5F);
- /* pop rbp */
+ /* pop %rbp */
EMIT1(0x5D);
/* ret */
@@ -300,8 +300,8 @@ static void emit_bpf_tail_call(u8 **pprog)
* if (index >= array->map.max_entries)
* goto out;
*/
- EMIT2(0x89, 0xD2); /* mov edx, edx */
- EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
+ EMIT2(0x89, 0xD2); /* mov %edx, %edx */
+ EMIT3(0x39, 0x56, /* cmp %edx, 0x10(%rsi) */
offsetof(struct bpf_array, map.max_entries));
#define OFFSET1 (35 + RETPOLINE_RAX_BPF_JIT_SIZE) /* Number of bytes to jump */
EMIT2(X86_JBE, OFFSET1); /* jbe out */
@@ -311,31 +311,31 @@ static void emit_bpf_tail_call(u8 **pprog)
* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
* goto out;
*/
- EMIT3(0x8B, 0x45, 0xD4); /* mov eax, dword ptr [rbp - 44] */
- EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
+ EMIT3(0x8B, 0x45, 0xD4); /* mov -0x2c(%rbp), %eax */
+ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp MAX_TAIL_CALL_CNT, %eax */
#define OFFSET2 (27 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JA, OFFSET2); /* ja out */
label2 = cnt;
- EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
- EMIT3(0x89, 0x45, 0xD4); /* mov dword ptr [rbp - 44], eax */
+ EMIT3(0x83, 0xC0, 0x01); /* add $0x1, %eax */
+ EMIT3(0x89, 0x45, 0xD4); /* mov %eax, -0x2c(%rbp) */
/* prog = array->ptrs[index]; */
- EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov rax, [rsi + rdx * 8 + offsetof(...)] */
+ EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov offsetof(ptrs)(%rsi,%rdx,8), %rax */
offsetof(struct bpf_array, ptrs));
/*
* if (prog == NULL)
* goto out;
*/
- EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
+ EMIT3(0x48, 0x85, 0xC0); /* test %rax, %rax */
#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JE, OFFSET3); /* je out */
label3 = cnt;
/* goto *(prog->bpf_func + prologue_size); */
- EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */
+ EMIT4(0x48, 0x8B, 0x40, /* mov offsetof(bpf_func)(%rax), %rax */
offsetof(struct bpf_prog, bpf_func));
- EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */
+ EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add $PROLOGUE_SIZE, %rax */
/*
* Wow we're ready to jump into next BPF program
@@ -359,11 +359,11 @@ static void emit_mov_imm32(u8 **pprog, bool sign_propagate,
int cnt = 0;
/*
- * Optimization: if imm32 is positive, use 'mov %eax, imm32'
+ * Optimization: if imm32 is positive, use 'mov imm32, %eax'
* (which zero-extends imm32) to save 2 bytes.
*/
if (sign_propagate && (s32)imm32 < 0) {
- /* 'mov %rax, imm32' sign extends imm32 */
+ /* 'mov imm32, %rax' sign extends imm32 */
b1 = add_1mod(0x48, dst_reg);
b2 = 0xC7;
b3 = 0xC0;
@@ -384,7 +384,7 @@ static void emit_mov_imm32(u8 **pprog, bool sign_propagate,
goto done;
}
- /* mov %eax, imm32 */
+ /* mov imm32, %eax */
if (is_ereg(dst_reg))
EMIT1(add_1mod(0x40, dst_reg));
EMIT1_off32(add_1reg(0xB8, dst_reg), imm32);
@@ -403,11 +403,11 @@ static void emit_mov_imm64(u8 **pprog, u32 dst_reg,
* For emitting plain u32, where sign bit must not be
* propagated LLVM tends to load imm64 over mov32
* directly, so save couple of bytes by just doing
- * 'mov %eax, imm32' instead.
+ * 'mov imm32, %eax' instead.
*/
emit_mov_imm32(&prog, false, dst_reg, imm32_lo);
} else {
- /* movabsq %rax, imm64 */
+ /* movabs imm64, %rax */
EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
EMIT(imm32_lo, 4);
EMIT(imm32_hi, 4);
@@ -422,10 +422,10 @@ static void emit_mov_reg(u8 **pprog, bool is64, u32 dst_reg, u32 src_reg)
int cnt = 0;
if (is64) {
- /* mov dst, src */
+ /* mov src, dst */
EMIT_mov(dst_reg, src_reg);
} else {
- /* mov32 dst, src */
+ /* mov32 src, dst */
if (is_ereg(dst_reg) || is_ereg(src_reg))
EMIT1(add_2mod(0x40, dst_reg, src_reg));
EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg));
@@ -571,43 +571,43 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
case BPF_ALU64 | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
- EMIT1(0x50); /* push rax */
- EMIT1(0x52); /* push rdx */
+ EMIT1(0x50); /* push %rax */
+ EMIT1(0x52); /* push %rdx */
if (BPF_SRC(insn->code) == BPF_X)
- /* mov r11, src_reg */
+ /* mov src_reg, %r11 */
EMIT_mov(AUX_REG, src_reg);
else
- /* mov r11, imm32 */
+ /* mov imm32, %r11 */
EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
- /* mov rax, dst_reg */
+ /* mov dst_reg, %rax */
EMIT_mov(BPF_REG_0, dst_reg);
/*
- * xor edx, edx
- * equivalent to 'xor rdx, rdx', but one byte less
+ * xor %edx, %edx
+ * equivalent to 'xor %rdx, %rdx', but one byte less
*/
EMIT2(0x31, 0xd2);
if (BPF_CLASS(insn->code) == BPF_ALU64)
- /* div r11 */
+ /* div %r11 */
EMIT3(0x49, 0xF7, 0xF3);
else
- /* div r11d */
+ /* div %r11d */
EMIT3(0x41, 0xF7, 0xF3);
if (BPF_OP(insn->code) == BPF_MOD)
- /* mov r11, rdx */
+ /* mov %r11, %rdx */
EMIT3(0x49, 0x89, 0xD3);
else
- /* mov r11, rax */
+ /* mov %r11, %rax */
EMIT3(0x49, 0x89, 0xC3);
- EMIT1(0x5A); /* pop rdx */
- EMIT1(0x58); /* pop rax */
+ EMIT1(0x5A); /* pop %rdx */
+ EMIT1(0x58); /* pop %rax */
- /* mov dst_reg, r11 */
+ /* mov %r11, dst_reg */
EMIT_mov(dst_reg, AUX_REG);
break;
@@ -619,11 +619,11 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
if (dst_reg != BPF_REG_0)
- EMIT1(0x50); /* push rax */
+ EMIT1(0x50); /* push %rax */
if (dst_reg != BPF_REG_3)
- EMIT1(0x52); /* push rdx */
+ EMIT1(0x52); /* push %rdx */
- /* mov r11, dst_reg */
+ /* mov dst_reg, %r11 */
EMIT_mov(AUX_REG, dst_reg);
if (BPF_SRC(insn->code) == BPF_X)
@@ -635,15 +635,15 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
EMIT1(add_1mod(0x48, AUX_REG));
else if (is_ereg(AUX_REG))
EMIT1(add_1mod(0x40, AUX_REG));
- /* mul(q) r11 */
+ /* mul(q) %r11 */
EMIT2(0xF7, add_1reg(0xE0, AUX_REG));
if (dst_reg != BPF_REG_3)
- EMIT1(0x5A); /* pop rdx */
+ EMIT1(0x5A); /* pop %rdx */
if (dst_reg != BPF_REG_0) {
- /* mov dst_reg, rax */
+ /* mov %rax, dst_reg */
EMIT_mov(dst_reg, BPF_REG_0);
- EMIT1(0x58); /* pop rax */
+ EMIT1(0x58); /* pop %rax */
}
break;
}
@@ -678,21 +678,21 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
case BPF_ALU64 | BPF_RSH | BPF_X:
case BPF_ALU64 | BPF_ARSH | BPF_X:
- /* Check for bad case when dst_reg == rcx */
+ /* Check for bad case when dst_reg == %rcx */
if (dst_reg == BPF_REG_4) {
- /* mov r11, dst_reg */
+ /* mov dst_reg, %r11 */
EMIT_mov(AUX_REG, dst_reg);
dst_reg = AUX_REG;
}
if (src_reg != BPF_REG_4) { /* common case */
- EMIT1(0x51); /* push rcx */
+ EMIT1(0x51); /* push %rcx */
- /* mov rcx, src_reg */
+ /* mov src_reg, %rcx */
EMIT_mov(BPF_REG_4, src_reg);
}
- /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
+ /* shl %cl, %rax | shr %cl, %rax | sar %cl, %rax */
if (BPF_CLASS(insn->code) == BPF_ALU64)
EMIT1(add_1mod(0x48, dst_reg));
else if (is_ereg(dst_reg))
@@ -706,23 +706,23 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
EMIT2(0xD3, add_1reg(b3, dst_reg));
if (src_reg != BPF_REG_4)
- EMIT1(0x59); /* pop rcx */
+ EMIT1(0x59); /* pop %rcx */
if (insn->dst_reg == BPF_REG_4)
- /* mov dst_reg, r11 */
+ /* mov %r11, dst_reg */
EMIT_mov(insn->dst_reg, AUX_REG);
break;
case BPF_ALU | BPF_END | BPF_FROM_BE:
switch (imm32) {
case 16:
- /* Emit 'ror %ax, 8' to swap lower 2 bytes */
+ /* Emit 'ror $0x8, %ax' to swap lower 2 bytes */
EMIT1(0x66);
if (is_ereg(dst_reg))
EMIT1(0x41);
EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);
- /* Emit 'movzwl eax, ax' */
+ /* Emit 'movzwl %ax, %eax' */
if (is_ereg(dst_reg))
EMIT3(0x45, 0x0F, 0xB7);
else
@@ -730,7 +730,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
break;
case 32:
- /* Emit 'bswap eax' to swap lower 4 bytes */
+ /* Emit 'bswap %eax' to swap lower 4 bytes */
if (is_ereg(dst_reg))
EMIT2(0x41, 0x0F);
else
@@ -738,7 +738,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
EMIT1(add_1reg(0xC8, dst_reg));
break;
case 64:
- /* Emit 'bswap rax' to swap 8 bytes */
+ /* Emit 'bswap %rax' to swap 8 bytes */
EMIT3(add_1mod(0x48, dst_reg), 0x0F,
add_1reg(0xC8, dst_reg));
break;
@@ -749,7 +749,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
switch (imm32) {
case 16:
/*
- * Emit 'movzwl eax, ax' to zero extend 16-bit
+ * Emit 'movzwl %ax, %eax' to zero extend 16-bit
* into 64 bit
*/
if (is_ereg(dst_reg))
@@ -759,7 +759,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
break;
case 32:
- /* Emit 'mov eax, eax' to clear upper 32-bits */
+ /* Emit 'mov %eax, %eax' to clear upper 32-bits */
if (is_ereg(dst_reg))
EMIT1(0x45);
EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
@@ -811,7 +811,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
/* STX: *(u8*)(dst_reg + off) = src_reg */
case BPF_STX | BPF_MEM | BPF_B:
- /* Emit 'mov byte ptr [rax + off], al' */
+ /* Emit 'mov %al, off(%rax)' */
if (is_ereg(dst_reg) || is_ereg(src_reg) ||
/* We have to add extra byte for x86 SIL, DIL regs */
src_reg == BPF_REG_1 || src_reg == BPF_REG_2)
@@ -850,22 +850,22 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
/* LDX: dst_reg = *(u8*)(src_reg + off) */
case BPF_LDX | BPF_MEM | BPF_B:
- /* Emit 'movzx rax, byte ptr [rax + off]' */
+ /* Emit 'movzbl off(%rax), %rax' */
EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
goto ldx;
case BPF_LDX | BPF_MEM | BPF_H:
- /* Emit 'movzx rax, word ptr [rax + off]' */
+ /* Emit 'movzwl off(%rax), %rax' */
EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
goto ldx;
case BPF_LDX | BPF_MEM | BPF_W:
- /* Emit 'mov eax, dword ptr [rax+0x14]' */
+ /* Emit 'mov 0x14(%rax), %eax' */
if (is_ereg(dst_reg) || is_ereg(src_reg))
EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
else
EMIT1(0x8B);
goto ldx;
case BPF_LDX | BPF_MEM | BPF_DW:
- /* Emit 'mov rax, qword ptr [rax+0x14]' */
+ /* Emit 'mov 0x14(%rax), %rax' */
EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
ldx:
/*
@@ -889,7 +889,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
/* STX XADD: lock *(u32*)(dst_reg + off) += src_reg */
case BPF_STX | BPF_XADD | BPF_W:
- /* Emit 'lock add dword ptr [rax + off], eax' */
+ /* Emit 'lock add %eax, off(%rax)' */
if (is_ereg(dst_reg) || is_ereg(src_reg))
EMIT3(0xF0, add_2mod(0x40, dst_reg, src_reg), 0x01);
else
@@ -949,7 +949,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
case BPF_JMP32 | BPF_JSLT | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_X:
- /* cmp dst_reg, src_reg */
+ /* cmp src_reg, dst_reg */
if (BPF_CLASS(insn->code) == BPF_JMP)
EMIT1(add_2mod(0x48, dst_reg, src_reg));
else if (is_ereg(dst_reg) || is_ereg(src_reg))
@@ -959,7 +959,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
case BPF_JMP | BPF_JSET | BPF_X:
case BPF_JMP32 | BPF_JSET | BPF_X:
- /* test dst_reg, src_reg */
+ /* test src_reg, dst_reg */
if (BPF_CLASS(insn->code) == BPF_JMP)
EMIT1(add_2mod(0x48, dst_reg, src_reg));
else if (is_ereg(dst_reg) || is_ereg(src_reg))
@@ -969,7 +969,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_K:
- /* test dst_reg, imm32 */
+ /* test imm32, dst_reg */
if (BPF_CLASS(insn->code) == BPF_JMP)
EMIT1(add_1mod(0x48, dst_reg));
else if (is_ereg(dst_reg))
@@ -997,7 +997,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_K:
- /* cmp dst_reg, imm8/32 */
+ /* cmp imm8/32, dst_reg */
if (BPF_CLASS(insn->code) == BPF_JMP)
EMIT1(add_1mod(0x48, dst_reg));
else if (is_ereg(dst_reg))
--
2.20.1