ARM: net: bpf: move stack documentation

commit 70ec3a6c2c11e4b0e107a65de943a082f9aff351 upstream.

Move the stack documentation towards the top of the file, where it's
relevant for things like the register layout.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index d00a0eb0386ee9ff912b552b02e004379ecc31d8..e90229d58c77fbad736d74a95f7750c0c46c96a2 100644 (file)
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -27,6 +27,27 @@
 
 int bpf_jit_enable __read_mostly;
 
+/*
+ * eBPF prog stack layout
+ *
+ *                         high
+ * original ARM_SP =>     +-----+ eBPF prologue
+ *                        |FP/LR|
+ * current ARM_FP =>      +-----+
+ *                        | ... | callee saved registers
+ * eBPF fp register =>    +-----+ <= (BPF_FP)
+ *                        | ... | eBPF JIT scratch space
+ *                        |     | eBPF prog stack
+ *                        +-----+
+ *                        |RSVD | JIT scratchpad
+ * current ARM_SP =>      +-----+ <= (BPF_FP - STACK_SIZE)
+ *                        |     |
+ *                        | ... | Function call stack
+ *                        |     |
+ *                        +-----+
+ *                          low
+ */
+
 #define STACK_OFFSET(k)        (k)
 #define TMP_REG_1      (MAX_BPF_JIT_REG + 0)   /* TEMP Register 1 */
 #define TMP_REG_2      (MAX_BPF_JIT_REG + 1)   /* TEMP Register 2 */
@@ -1091,27 +1112,6 @@ static void build_prologue(struct jit_ctx *ctx)
 
        u16 reg_set = 0;
 
-       /*
-        * eBPF prog stack layout
-        *
-        *                         high
-        * original ARM_SP =>     +-----+ eBPF prologue
-        *                        |FP/LR|
-        * current ARM_FP =>      +-----+
-        *                        | ... | callee saved registers
-        * eBPF fp register =>    +-----+ <= (BPF_FP)
-        *                        | ... | eBPF JIT scratch space
-        *                        |     | eBPF prog stack
-        *                        +-----+
-        *                        |RSVD | JIT scratchpad
-        * current A64_SP =>      +-----+ <= (BPF_FP - STACK_SIZE)
-        *                        |     |
-        *                        | ... | Function call stack
-        *                        |     |
-        *                        +-----+
-        *                          low
-        */
-
        /* Save callee saved registers. */
        reg_set |= (1<<r4) | (1<<r5) | (1<<r6) | (1<<r7) | (1<<r8) | (1<<r10);
 #ifdef CONFIG_FRAME_POINTER