[PATCH 4.14 17/71] ARM: net: bpf: move stack documentation

From: Greg Kroah-Hartman
Date: Mon Jan 29 2018 - 16:08:36 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/arm/net/bpf_jit_32.c | 42 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)

--- 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_ct

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